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Zhou L, Peng Q, Tang W, Wu N, Yang L, Qi L, Li J, Huang Y. Magnetic Resonance Elastography of Anterior Mediastinal Tumors. J Magn Reson Imaging 2024. [PMID: 38855820 DOI: 10.1002/jmri.29481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/27/2024] [Accepted: 04/30/2024] [Indexed: 06/11/2024] Open
Abstract
BACKGROUND Preoperative differentiation of the types of mediastinal tumors is essential. Magnetic resonance (MR) elastography potentially provides a noninvasive method to assess the classification of mediastinal tumor subtypes. PURPOSE To evaluate the use of MR elastography in anterior mediastinal masses and to characterize the mechanical properties of tumors of different subtypes. STUDY TYPE Prospective. SUBJECTS 189 patients with anterior mediastinal tumors (AMTs) confirmed by histopathology (62 thymomas, 53 thymic carcinomas, 57 lymphomas, and 17 germ cell tumors). FIELD STRENGTH/SEQUENCE A gradient echo-based 2D MR elastography sequence and a diffusion-weighted imaging (DWI) sequence at 3.0 T. ASSESSMENT Stiffness and apparent diffusion coefficients (ADC) were measured in AMTs using MR elastography-derived elastograms and DWI-derived ADC maps, respectively. The aim of this study is to identify whether MR elastography can differentiate between the histological subtypes of ATMs. STATISTICAL TESTS One-way analysis of variance (ANOVA), two-way ANOVA, Pearson's linear correlation coefficient (r), receiver operating characteristic (ROC) curve analysis; P < 0.05 was considered significant. RESULTS Lymphomas had significantly lower stiffness than other AMTs (4.0 ± 0.63 kPa vs. 4.8 ± 1.39 kPa). The mean stiffness of thymic carcinomas was significantly higher than that of other AMTs (5.6 ± 1.41 kPa vs. 4.2 ± 0.94 kPa). Using a cutoff value of 5.0 kPa, ROC analysis showed that lymphomas could be differentiated from other AMTs with an accuracy of 59%, sensitivity of 97%, and specificity of 38%. Using a cutoff value of 5.1 kPa, thymic carcinomas could be differentiated from other AMTs with an accuracy of 84%, sensitivity of 67%, and specificity of 90%. However, there was an overlap in the stiffness values of individual thymomas (4.2 ± 0.71; 3.9-4.5), thymic carcinomas (5.6 ± 1.41; 5.0-6.1), lymphomas (4.0 ± 0.63; 3.8-4.2), and germ cell tumors (4.5 ± 1.79; 3.3-5.6). DATA CONCLUSION MR elastography-derived stiffness may be used to evaluate AMTs of various histologies. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY Stage 2.
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Affiliation(s)
- Lina Zhou
- Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qin Peng
- Department of Radiology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Wei Tang
- Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ning Wu
- Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lin Yang
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Linlin Qi
- Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiang Li
- Office for Cancer Screening, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yao Huang
- Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Ge GR, Song W, Giannetto MJ, Rolland JP, Nedergaard M, Parker KJ. Mouse brain elastography changes with sleep/wake cycles, aging, and Alzheimer's disease. Neuroimage 2024; 295:120662. [PMID: 38823503 DOI: 10.1016/j.neuroimage.2024.120662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/05/2024] [Accepted: 05/30/2024] [Indexed: 06/03/2024] Open
Abstract
Understanding the physiological processes in aging and how neurodegenerative disorders affect cognitive function is a high priority for advancing human health. One specific area of recently enabled research is the in vivo biomechanical state of the brain. This study utilized reverberant optical coherence elastography, a high-resolution elasticity imaging method, to investigate stiffness changes during the sleep/wake cycle, aging, and Alzheimer's disease in murine models. Four-dimensional scans of 44 wildtype mice, 13 mice with deletion of aquaporin-4 water channel, and 12 mice with Alzheimer-related pathology (APP/PS1) demonstrated that (1) cortical tissue became softer (on the order of a 10% decrease in shear wave speed) when young wildtype mice transitioned from wake to anesthetized, yet this effect was lost in aging and with mice overexpressing amyloid-β or lacking the water channel AQP4. (2) Cortical stiffness increased with age in all mice lines, but wildtype mice exhibited the most prominent changes as a function of aging. The study provides novel insight into the brain's biomechanics, the constraints of fluid flow, and how the state of brain activity affects basic properties of cortical tissues.
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Affiliation(s)
- Gary R Ge
- The Institute of Optics, University of Rochester, 480 Intercampus Drive, Rochester, NY 14627, USA
| | - Wei Song
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Michael J Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Jannick P Rolland
- The Institute of Optics, University of Rochester, 480 Intercampus Drive, Rochester, NY 14627, USA; Department of Biomedical Engineering, University of Rochester, 204 Robert B. Goergen Hall, Rochester, NY 14627, USA; Center for Visual Science, University of Rochester, 361 Meliora Hall, Rochester, NY 14627, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA; Center for Translational Neuromedicine, University of Copenhagen, Blegdamsvej 3B, 2200-N, Denmark.
| | - Kevin J Parker
- Department of Biomedical Engineering, University of Rochester, 204 Robert B. Goergen Hall, Rochester, NY 14627, USA; Department of Electrical and Computer Engineering, University of Rochester, 500 Computer Studies Building, Rochester, NY 14627, USA; Department of Imaging Sciences (Radiology), University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Caban-Rivera DA, Williams LT, McGarry MDJ, Smith DR, Van Houten EEW, Paulsen KD, Bayly PV, Johnson CL. Mechanical Properties of White Matter Tracts in Aging Assessed via Anisotropic MR Elastography. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593260. [PMID: 38766139 PMCID: PMC11100698 DOI: 10.1101/2024.05.08.593260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Magnetic resonance elastography (MRE) is a promising neuroimaging technique to probe tissue microstructure, which has revealed widespread softening with loss of structural integrity in the aging brain. Traditional MRE approaches assume mechanical isotropy. However, white matter is known to be anisotropic from aligned, myelinated axonal bundles, which can lead to uncertainty in mechanical property estimates in these areas when using isotropic MRE. Recent advances in anisotropic MRE now allow for estimation of shear and tensile anisotropy, along with substrate shear modulus, in white matter tracts. The objective of this study was to investigate age-related differences in anisotropic mechanical properties in human brain white matter tracts for the first time. Anisotropic mechanical properties in all tracts were found to be significantly lower in older adults compared to young adults, with average property differences ranging between 0.028-0.107 for shear anisotropy and between 0.139-0.347 for tensile anisotropy. Stiffness perpendicular to the axonal fiber direction was also significantly lower in older age, but only in certain tracts. When compared with fractional anisotropy measures from diffusion tensor imaging, we found that anisotropic MRE measures provided additional, complementary information in describing differences between the white matter integrity of young and older populations. Anisotropic MRE provides a new tool for studying white matter structural integrity in aging and neurodegeneration.
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Mark IT, Karki P, Cutsforth-Gregory J, Brinjikji W, Madhavan AA, Messina SA, Cogswell PM, Chen JJ, Ehman RL, Huston J, Murphy MC. Evaluation of MR Elastography as a Noninvasive Diagnostic Test for Spontaneous Intracranial Hypotension. AJNR Am J Neuroradiol 2024; 45:662-667. [PMID: 38485194 DOI: 10.3174/ajnr.a8162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/03/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND AND PURPOSE Spontaneous intracranial hypotension is a condition resulting from a leak of CSF from the spinal canal arising independent of a medical procedure. Spontaneous intracranial hypotension can present with normal brain MR imaging findings and nonspecific symptoms, leading to the underdiagnosis in some patients and unnecessary invasive myelography in others who are found not to have the condition. Given the likelihood that spontaneous intracranial hypotension alters intracranial biomechanics, the goal of this study was to evaluate MR elastography as a potential noninvasive test to diagnose the condition. MATERIALS AND METHODS We performed MR elastography in 15 patients with confirmed spontaneous intracranial hypotension from September 2022 to April 2023. Age, sex, symptom duration, and brain MR imaging Bern score were collected. MR elastography data were used to compute stiffness and damping ratio maps, and voxelwise modeling was performed to detect clusters of significant differences in mechanical properties between patients with spontaneous intracranial hypotension and healthy control participants. To evaluate diagnostic accuracy, we summarized each examination by 2 spatial pattern scores (one each for stiffness and damping ratio) and evaluated group-wise discrimination by receiver operating characteristic curve analysis. RESULTS Patients with spontaneous intracranial hypotension exhibited significant differences in both stiffness and damping ratio (false discovery rate-corrected, Q < 0.05). Pattern analysis discriminated patients with spontaneous intracranial hypotension from healthy controls with an area under the curve of 0.97 overall, and the area under the curve was 0.97 in those without MR imaging findings of spontaneous intracranial hypotension. CONCLUSIONS Results from this pilot study demonstrate MR elastography as a potential imaging biomarker and a noninvasive method for diagnosing spontaneous intracranial hypotension, including patients with normal brain MR imaging findings.
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Affiliation(s)
- Ian T Mark
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | - Pragalv Karki
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | | | - Waleed Brinjikji
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | - Ajay A Madhavan
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | - Steven A Messina
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | - Petrice M Cogswell
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | - John J Chen
- Department of Neurology (J.C.-G., J.J.C.), Mayo Clinic, Rochester, Minnesota
- Department of Ophthalmology (J.J.C.), Mayo Clinic, Rochester, Minnesota
| | - Richard L Ehman
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | - John Huston
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
| | - Matthew C Murphy
- From the Department of Radiology (I.T.M., P.K., W.B., A.A.M., S.A.M., P.M.C., R.L.E., J.H., M.C.M.), Mayo Clinic, Rochester, Minnesota
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Hojo E, Glaser KJ, Harada-Hayashi A, Le Y, Chen J, Hulshizer TC, Rossman PJ, Noyori S, Roberts N. Feasibility study of the application of magnetic resonance elastography (MRE) to measure oral posture related changes in stiffness of zygomaticus major muscle. Magn Reson Imaging 2024; 111:196-201. [PMID: 38723783 DOI: 10.1016/j.mri.2024.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/20/2024] [Accepted: 05/06/2024] [Indexed: 05/24/2024]
Abstract
PURPOSE Development of a technique for measuring the mechanical properties of zygomaticus major (ZM) may aid advances in clinical treatments for correcting abnormal oral posture. The objective of this work was to demonstrate the feasibility of measuring the stiffness of ZM using an MR elastography technique that incorporates a custom local driver and a phase-gradient (PG) inversion. METHODS 2D MRE investigations were performed for 3 healthy subjects using a vibration frequency of 90 Hz to test the prediction that the stiffness of ZM would be greater in the mouth-open compared to the mouth-closed position. MRE wave images were acquired along the long axis of ZM and processed using a 2D spatial-temporal directional filter applied in the direction of wave propagation along the long axis of the muscle. Stiffness measurements were obtained by applying the PG technique to a 1D-profile drawn in the phase image of the first harmonic of the wave images and a one-tailed paired t-test was used to compare the ZM stiffness between the two mouth postures (p < 0.05). RESULTS The mean stiffness and standard deviation (SD) of ZM across the three participants in the mouth-closed and mouth-open postures was 6.75 kPa (SD 3.36 kPa) and 15.5 kPa (SD 5.15 kPa), respectively. Changes of ZM stiffness were significantly greater in the mouth-open than the mouth-closed posture (p = 0.038). CONCLUSION The feasibility of using the PG MRE technique to measure stiffness changes in a small muscle such as ZM for different mouth postures has been demonstrated. Further investigations are required in a larger cohort of participants to investigate the sensitivity and reproducibility of the technique for potential clinical application as well as in health and beauty related studies.
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Affiliation(s)
- Emi Hojo
- Centre for Reproductive Health (CRH), Institute for Regeneration and Repair (IRR), 4-5 Little France Drive, Edinburgh EH16 4UU, UK; Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Kevin J Glaser
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Ayako Harada-Hayashi
- Rohto Pharmaceutical Company, 1-8-1, Tatsumi-nishi, Ikunoku, Osaka 544-8666, Japan
| | - Yuan Le
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Jun Chen
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA; Department of Radiology, Nanjing Drum Tower Hospital, 321 Zhongshan Rd, Gulou, Nanjing, Jiangsu 210008, China; Resoundant, Inc., 421 1st Ave SW, Rochester, MN, USA
| | - Thomas C Hulshizer
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Phillip J Rossman
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Sachiko Noyori
- Rohto Pharmaceutical Company, 1-8-1, Tatsumi-nishi, Ikunoku, Osaka 544-8666, Japan
| | - Neil Roberts
- Centre for Reproductive Health (CRH), Institute for Regeneration and Repair (IRR), 4-5 Little France Drive, Edinburgh EH16 4UU, UK.
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Le Y, Chen J, Rossman P, Bolster B, Kannengiesser S, Manduca A, Glaser K, Sui Y, Huston J, Yin Z, Ehman RL. Wavelet MRE: Imaging propagating broadband acoustic waves with wavelet-based motion-encoding gradients. Magn Reson Med 2024; 91:1923-1935. [PMID: 38098427 PMCID: PMC10950519 DOI: 10.1002/mrm.29972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/24/2023] [Accepted: 11/26/2023] [Indexed: 03/20/2024]
Abstract
PURPOSE To demonstrate a novel MR elastography (MRE) technique, termed here wavelet MRE. With this technique, broadband motion sensitivity is achievable. Moreover, the true tissue displacement can be reconstructed with a simple inverse transform. METHODS A wavelet MRE sequence was developed with motion-encoding gradients based on Haar wavelets. From the phase images' displacement was estimated using an inverse transform. Simulations were performed using a frequency sweep and a transient as ground-truth motions. A PVC phantom was scanned using wavelet MRE and standard MRE with both transient (one and 10 cycles of 90-Hz motion) and steady-state dual-frequency motion (30 and 60 Hz) for comparison. The technique was tested in a human brain, and motion trajectories were estimated for each voxel. RESULTS In simulation, the displacement information estimated from wavelet MRE closely matched the true motion. In the phantom test, the MRE phase data generated from the displacement information derived from wavelet MRE agreed well with standard MRE data. Testing of wavelet MRE to assess transient motion waveforms in the brain was successful, and the tissue motion observed was consistent with a previous study. CONCLUSION The uniform and broadband frequency response of wavelet MRE makes it a promising method for imaging transient, multifrequency motion, or motion with unknown frequency content. One potential application is measuring the response of brain tissue undergoing low-amplitude, transient vibrations as a model for the study of traumatic brain injury.
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Affiliation(s)
- Yuan Le
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - Jun Chen
- Department of Radiology, Mayo Clinic, Rochester, MN
| | | | - Bradley Bolster
- MR Collaborations, Siemens Medical Solutions USA, Inc., Malvern, PA, USA
| | | | | | - Kevin Glaser
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - Yi Sui
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - John Huston
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - Ziying Yin
- Department of Radiology, Mayo Clinic, Rochester, MN
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McIlvain G, Magoon EM, Clements RG, Merritt A, Hiscox LV, Schwarb H, Johnson CL. Acute effects of high-intensity exercise on brain mechanical properties and cognitive function. Brain Imaging Behav 2024:10.1007/s11682-024-00873-y. [PMID: 38538876 DOI: 10.1007/s11682-024-00873-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2024] [Indexed: 04/26/2024]
Abstract
Previous studies have shown that engagement in even a single session of exercise can improve cognitive performance in the short term. However, the underlying physiological mechanisms contributing to this effect are still being studied. Recently, with improvements to advanced quantitative neuroimaging techniques, brain tissue mechanical properties can be sensitively and noninvasively measured with magnetic resonance elastography (MRE) and regional brain mechanical properties have been shown to reflect individual cognitive performance. Here we assess brain mechanical properties before and immediately after engagement in a high-intensity interval training (HIIT) regimen, as well as one-hour post-exercise. We find that immediately after exercise, subjects in the HIIT group had an average global brain stiffness decrease of 4.2% (p < 0.001), and an average brain damping ratio increase of 3.1% (p = 0.002). In contrast, control participants who did not engage in exercise showed no significant change over time in either stiffness or damping ratio. Changes in brain mechanical properties with exercise appeared to be regionally dependent, with the hippocampus decreasing in stiffness by 10.4%. We also found that one-hour after exercise, brain mechanical properties returned to initial baseline values. The magnitude of changes to brain mechanical properties also correlated with improvements in reaction time on executive control tasks (Eriksen Flanker and Stroop) with exercise. Understanding the neural changes that arise in response to exercise may inform potential mechanisms behind improvements to cognitive performance with acute exercise.
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Affiliation(s)
- Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Emily M Magoon
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Rebecca G Clements
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Alexis Merritt
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Lucy V Hiscox
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Hillary Schwarb
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA.
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Gholampour S. Feasibility of assessing non-invasive intracranial compliance using FSI simulation-based and MR elastography-based brain stiffness. Sci Rep 2024; 14:6493. [PMID: 38499758 PMCID: PMC10948846 DOI: 10.1038/s41598-024-57250-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/15/2024] [Indexed: 03/20/2024] Open
Abstract
Intracranial compliance (ICC) refers to the change in intracranial volume per unit change in intracranial pressure (ICP). Magnetic resonance elastography (MRE) quantifies brain stiffness by measuring the shear modulus. Our objective is to investigate the relationship between ICC and brain stiffness through fluid-structure interaction (FSI) simulation, and to explore the feasibility of using MRE to assess ICC based on brain stiffness. This is invaluable due to the clinical importance of ICC, as well as the fast and non-invasive nature of the MRE procedure. We employed FSI simulation in hydrocephalus patients with aqueductal stenosis to non-invasively calculate ICP which is the basis of the calculation of ICC and FSI-based brain stiffness. The FSI simulated parameters used have been validated with experimental data. Our results showed that there is no relationship between FSI simulated-based brain stiffness and ICC in hydrocephalus patients. However, MRE-based brain stiffness may be sensitive to changes in intracranial fluid dynamic parameters such as cerebral perfusion pressure (CPP), cerebral blood flow (CBF), and ICP, as well as to mechano-vascular changes in the brain, which are determining parameters in ICC assessment. Although optimism has been found regarding the assessment of ICC using MRE-based brain stiffness, especially for acute-onset brain disorders, further studies are necessary to clarify their direct relationship.
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Affiliation(s)
- Seifollah Gholampour
- Department of Neurological Surgery, The University of Chicago, 5841 S. Maryland Ave, Chicago, IL, 60637, USA.
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Yu J, Guo H, Qiao X, Jiang L, Chen Y, Liu J, Zhang C, Su X, Zhang H, Wan M. Transcranial ultrasound estimation of viscoelasticity and fluidity in brain tumors aided by transcranial shear waves. ULTRASONICS 2024; 138:107262. [PMID: 38330769 DOI: 10.1016/j.ultras.2024.107262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/06/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
Cerebral diseases, such as brain tumors, are intricately linked to the mechanical properties of brain tissues. Estimating the mechanical properties of brain tumors using transcranial ultrasound is a promising approach. However, the complexity of cranial features introduces challenges, such as ultrasound attenuation and interference from multidirectional transcranial shear waves induced by impact vibrations. To address these issues, this study proposes a transcranial ultrasound estimation method assisted by transcranial shear vibrations. Transcranial vibrations apply shear forces on the parietal bone, inducing unidirectional transcranial shear waves within brain tissue, as validated through simulations. Shear waves at different frequencies were captured via transcranial ultrasound, which were used to assess the viscoelasticity and fluidity of brain tumors. Transcranial experimental validations were conducted in 3D-printed models with tumor phantoms and ex vivo animal tumors. Vibration safety assessments were also performed. The results demonstrate that transcranial ultrasound can detect micron displacements induced by transcranial shear waves. In phantom and ex vivo animal experiments, speed distribution maps were employed to determine the size and location of one or two tumors enclosed in the skull model. The results revealed that the proposed approach could detect tumors with a minimum diameter of 0.8 cm and an inter-tumor distance of 0.8 cm. Notably, significant differences in viscoelasticity and fluidity between normal brain tissue and brain tumors were found (p<0.001). The maximum assessment errors for the elasticity, viscosity, and fluidity using transcranial ultrasound were 11.90%, 4.82%, and 0.73%, respectively, indicating that fluidity was more robust than viscoelasticity. The maximum accelerations of the skull were only 3.21 ms-2.
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Affiliation(s)
- Jianjun Yu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Hao Guo
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Xiaoyang Qiao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Liyuan Jiang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Yiran Chen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Jiacheng Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Chaoyang Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Xiao Su
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Hongmei Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China.
| | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China.
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Rasmussen AM, Friismose AI, Mussmann B, Lagerstrand K, Harbo FSG, Jensen J. Repeatability of diffusion-based stiffness prediction - A healthy volunteer study. Radiography (Lond) 2024; 30:524-530. [PMID: 38262191 DOI: 10.1016/j.radi.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/03/2024] [Accepted: 01/10/2024] [Indexed: 01/25/2024]
Abstract
INTRODUCTION The study investigated the repeatability of brain diffusion-based stiffness prediction (DWIstiff) in healthy volunteers. METHODS Thirty-one healthy volunteers were examined with DWIstiff using two different sets of b-values: b200-1500 s/mm2 (DWIstiff, 1500) and b200-1000 s/mm2 (DWIstiff, 1000). Each b-value set was scanned twice per imaging session without repositioning the participants. DWIstiff images were reconstructed from each set. Two observers delineated regions of interest (ROIs) on each DWIstiff image. The repeatability coefficient (RC), coefficient of variation (CV), inter- and intraobserver agreement were calculated. RESULTS After excluding three participants due to image artifacts, the study included twenty-eight volunteers (mean age (range)) 37 years (24-62), 10 males, 18 females). For DWIstiff, 1500, the lowest and the highest RCs were in the parietal lobe (0.52) and respectively the brain stem (1.17). The lowest RC for DWIstiff, 1000 was in the frontal lobe (0.42) and the highest in the brain stem (1.58). The CV for whole brain measurements was 3.83 % for DWIstiff, 1500 and 4.93 % for DWIstiff, 1000. The Bland‒Altman (BA) limits of agreement (LoA) for the intraobserver agreement of DWIstiff, 1500 were -0.90 to 1.06 and respectively -0.78 to 0.88 for DWIstiff, 1000. Regarding interobserver agreement, the LoA were -0.85 to 0.94 for DWIstiff, 1500 and -0.61 to 0.66 for DWIstiff, 1000. CONCLUSION DWIstiff is a precise technique with some observer dependence. Repeatability is higher for DWIstiff, 1000 s/mm2 than for DWIstiff 1500 s/mm2. IMPLICATIONS FOR PRACTICE Our findings suggest that DWIstiff can reliably detect stiffness changes larger than 4.93 % in healthy volunteers. Further studies should investigate whether the repeatability of DWIstiff may be affected by the presence of pathology such as a brain tumor.
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Affiliation(s)
- A-M Rasmussen
- Department of Radiology, Odense University Hospital, Odense, Denmark; Research and Innovation Unit of Radiology, University of Southern Denmark, Odense, Denmark
| | - A I Friismose
- Department of Radiology, Odense University Hospital, Odense, Denmark; Research and Innovation Unit of Radiology, University of Southern Denmark, Odense, Denmark.
| | - B Mussmann
- Department of Radiology, Odense University Hospital, Odense, Denmark; Research and Innovation Unit of Radiology, University of Southern Denmark, Odense, Denmark; Department of Life Sciences and Health, Radiography, Oslo Metropolitan University, Oslo, Norway
| | - K Lagerstrand
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden; Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - F S G Harbo
- Department of Radiology, Odense University Hospital, Odense, Denmark
| | - J Jensen
- Department of Radiology, Odense University Hospital, Odense, Denmark; Research and Innovation Unit of Radiology, University of Southern Denmark, Odense, Denmark
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11
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Milbocker KA, Williams LT, Caban-Rivera DA, Smith IF, Kurtz S, McGarry MDJ, Wattrisse B, Van Houten EEW, Johnson CL, Klintsova AY. Magnetic resonance elastography captures a transient benefit of exercise intervention on forebrain stiffness in a rat model of fetal alcohol spectrum disorders. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2024; 48:466-477. [PMID: 38225180 PMCID: PMC11162295 DOI: 10.1111/acer.15265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/04/2023] [Accepted: 12/29/2023] [Indexed: 01/17/2024]
Abstract
BACKGROUND Fetal alcohol spectrum disorders (FASD), a group of prevalent conditions resulting from prenatal alcohol exposure, affect the maturation of cerebral white matter as first identified with neuroimaging. However, traditional methods are unable to track subtle microstructural alterations to white matter. This preliminary study uses a highly sensitive and clinically translatable magnetic resonance elastography (MRE) protocol to assess brain tissue microstructure through its mechanical properties following an exercise intervention in a rat model of FASD. METHODS Female rat pups were either alcohol-exposed (AE) via intragastric intubation of alcohol in milk substitute (5.25 g/kg/day) or sham-intubated (SI) on postnatal days (PD) four through nine to model alcohol exposure during the brain growth spurt. On PD 30, half of AE and SI rats were randomly assigned to either a wheel-running or standard cage for 12 days. Magnetic resonance elastography was used to measure whole brain and callosal mechanical properties at the end of the intervention (around PD 42) and at 1 month post-intervention, and findings were validated with histological quantification of oligoglia. RESULTS Alcohol exposure reduced forebrain stiffness (p = 0.02) in standard-housed rats. The adolescent exercise intervention mitigated this effect, confirming that increased aerobic activity supports proper neurodevelopmental trajectories. Forebrain damping ratio was lowest in standard-housed AE rats (p < 0.01), but this effect was not mitigated by intervention exposure. At 1 month post-intervention, all rats exhibited comparable forebrain stiffness and damping ratio (p > 0.05). Callosal stiffness and damping ratio increased with age. With cessation of exercise, there was a negative rebound effect on the quantity of callosal oligodendrocytes, irrespective of treatment group, which diverged from our MRE results. CONCLUSIONS This is the first application of MRE to measure the brain's mechanical properties in a rodent model of FASD. MRE successfully captured alcohol-related changes in forebrain stiffness and damping ratio. Additionally, MRE identified an exercise-related increase to forebrain stiffness in AE rats.
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Affiliation(s)
- Katrina A. Milbocker
- Department of Psychological & Brain Sciences, University of Delaware, Newark, Delaware, USA
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | - L. Tyler Williams
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | | | - Ian F. Smith
- Department of Psychological & Brain Sciences, University of Delaware, Newark, Delaware, USA
| | - Samuel Kurtz
- Laboratorie de Mecanique et Genie Civil, CNRS, Universite de Montpellier, Montpellier, France
| | | | - Bertrand Wattrisse
- Laboratorie de Mecanique et Genie Civil, CNRS, Universite de Montpellier, Montpellier, France
| | | | - Curtis L. Johnson
- Department of Psychological & Brain Sciences, University of Delaware, Newark, Delaware, USA
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | - Anna Y. Klintsova
- Department of Psychological & Brain Sciences, University of Delaware, Newark, Delaware, USA
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12
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Feng Y, Murphy MC, Hojo E, Li F, Roberts N. Magnetic Resonance Elastography in the Study of Neurodegenerative Diseases. J Magn Reson Imaging 2024; 59:82-96. [PMID: 37084171 DOI: 10.1002/jmri.28747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 04/22/2023] Open
Abstract
Neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD) present a major health burden to society. Changes in brain structure and cognition are generally only observed at the late stage of the disease. Although advanced magnetic resonance imaging (MRI) techniques such as diffusion imaging may allow identification of biomarkers at earlier stages of neurodegeneration, early diagnosis is still challenging. Magnetic resonance elastography (MRE) is a noninvasive MRI technique for studying the mechanical properties of tissues by measuring the wave propagation induced in the tissues using a purpose-built actuator. Here, we present a systematic review of preclinical and clinical studies in which MRE has been applied to study neurodegenerative diseases. Actuator systems for data acquisition, inversion algorithms for data analysis, and sample demographics are described and tissue stiffness measures obtained for the whole brain and internal structures are summarized. A total of six animal studies and eight human studies have been published. The animal studies refer to 123 experimental animals (68 AD and 55 PD) and 121 wild-type animals, while the human studies refer to 142 patients with neurodegenerative disease (including 56 AD and 17 PD) and 166 controls. The animal studies are consistent in the reporting of decreased stiffness of the hippocampal region in AD mice. However, in terms of disease progression, although consistent decreases in either storage modulus or shear modulus magnitude are reported for whole brain, there is variation in the results reported for the hippocampal region. The clinical studies are consistent in reports of a significant decrease in either whole brain storage modulus or shear modulus magnitude, in both AD and PD and with different brain structures affected in different neurodegenerative diseases. MRE studies of neurodegenerative diseases are still in their infancy, and in future it will be interesting to investigate potential relationships between brain mechanical properties and clinical measures, which may help elucidate the mechanisms underlying onset and progression of neurodegenerative diseases. EVIDENCE LEVEL: 1. TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Yuan Feng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Department of Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Matthew C Murphy
- Department of Radiology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Emi Hojo
- Centre for Reproductive Health (CRH), School of Clinical Sciences, University of Edinburgh, Edinburgh, UK
| | - Fei Li
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Neil Roberts
- Centre for Reproductive Health (CRH), School of Clinical Sciences, University of Edinburgh, Edinburgh, UK
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13
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Burman Ingeberg M, Van Houten E, Zwanenburg JJM. Estimating the viscoelastic properties of the human brain at 7 T MRI using intrinsic MRE and nonlinear inversion. Hum Brain Mapp 2023; 44:6575-6591. [PMID: 37909395 PMCID: PMC10681656 DOI: 10.1002/hbm.26524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 11/03/2023] Open
Abstract
Intrinsic actuation magnetic resonance elastography (MRE) is a phase-contrast MRI technique that allows for in vivo quantification of mechanical properties of the brain by exploiting brain motion that arise naturally due to the cardiac pulse. The mechanical properties of the brain reflect its tissue microstructure, making it a potentially valuable parameter in studying brain disease. The main purpose of this study was to assess the feasibility of reconstructing the viscoelastic properties of the brain using high-quality 7 T MRI displacement measurements, obtained using displacement encoding with stimulated echoes (DENSE) and intrinsic actuation. The repeatability and sensitivity of the method for detecting normal regional variation in brain tissue properties was assessed as secondary goal. The displacement measurements used in this analysis were previously acquired for a separate study, where eight healthy subjects (27 ± 7 years) were imaged with repeated scans (spatial resolution approx. 2 mm isotropic, temporal resolution 75 ms, motion sensitivity 0.35 mm/2π for displacements in anterior-posterior and left-right directions, and 0.7 mm/2π for feet-head displacements). The viscoelastic properties of the brain were estimated using a subzone based non-linear inversion scheme. The results show comparable consistency to that of extrinsic MRE between the viscoelastic property maps obtained from repeated displacement measurements. The shear stiffness maps showed fairly consistent spatial patterns. The whole-brain repeatability coefficient (RC) for shear stiffness was (mean ± standard deviation) 8 ± 8% relative to the mean whole-brain stiffness, and the damping ratio RC was 28 ± 17% relative to the whole-brain damping ratio. The shear stiffness maps showed similar statistically significant regional trends as demonstrated in a publicly available atlas of viscoelastic properties obtained with extrinsic actuation MRE at 50 Hz. The damping ratio maps showed less consistency, likely due to data-model mismatch of describing the brain as a viscoelastic material under low frequencies. While artifacts induced by fluid flow within the brain remain a limitation of the technique in its current state, intrinsic actuation based MRE allow for consistent and repeatable estimation of the mechanical properties of the brain. The method provides enough sensitivity to investigate regional variation in such properties in the normal brain, which is likely sufficient to also investigate pathological changes.
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14
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Khair AM, McIlvain G, McGarry MDJ, Kandula V, Yue X, Kaur G, Averill LW, Choudhary AK, Johnson CL, Nikam RM. Clinical application of magnetic resonance elastography in pediatric neurological disorders. Pediatr Radiol 2023; 53:2712-2722. [PMID: 37794174 PMCID: PMC11086054 DOI: 10.1007/s00247-023-05779-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/06/2023]
Abstract
Magnetic resonance elastography is a relatively new, rapidly evolving quantitative magnetic resonance imaging technique which can be used for mapping the viscoelastic mechanical properties of soft tissues. MR elastography measurements are akin to manual palpation but with the advantages of both being quantitative and being useful for regions which are not available for palpation, such as the human brain. MR elastography is noninvasive, well tolerated, and complements standard radiological and histopathological studies by providing in vivo measurements that reflect tissue microstructural integrity. While brain MR elastography studies in adults are becoming frequent, published studies on the utility of MR elastography in children are sparse. In this review, we have summarized the major scientific principles and recent clinical applications of brain MR elastography in diagnostic neuroscience and discuss avenues for impact in assessing the pediatric brain.
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Affiliation(s)
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | | | - Vinay Kandula
- Department of Radiology, Nemours Children's Hospital, Wilmington, DE, USA
| | - Xuyi Yue
- Department of Radiology, Nemours Children's Hospital, Wilmington, DE, USA
- Department of Biomedical Research, Nemours Children's Hospital, Wilmington, DE, USA
| | - Gurcharanjeet Kaur
- Department of Neurology, New York-Presbyterian / Columbia University Irving Medical Center, New York, NY, USA
| | - Lauren W Averill
- Department of Radiology, Nemours Children's Hospital, Wilmington, DE, USA
| | - Arabinda K Choudhary
- Department of Radiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
- Department of Biomedical Research, Nemours Children's Hospital, Wilmington, DE, USA
| | - Rahul M Nikam
- Department of Radiology, Nemours Children's Hospital, Wilmington, DE, USA.
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15
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Sanjana F, Delgorio PL, DeConne TM, Hiscox LV, Pohlig RT, Johnson CL, Martens CR. Vascular determinants of hippocampal viscoelastic properties in healthy adults across the lifespan. J Cereb Blood Flow Metab 2023; 43:1931-1941. [PMID: 37395479 PMCID: PMC10676145 DOI: 10.1177/0271678x231186571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 07/04/2023]
Abstract
Arterial stiffness and cerebrovascular pulsatility are non-traditional risk factors of Alzheimer's disease. However, there is a gap in understanding the earliest mechanisms that link these vascular determinants to brain aging. Changes to mechanical tissue properties of the hippocampus (HC), a brain structure essential for memory encoding, may reflect the impact of vascular dysfunction on brain aging. We tested the hypothesis that arterial stiffness and cerebrovascular pulsatility are related to HC tissue properties in healthy adults across the lifespan. Twenty-five adults underwent measurements of brachial blood pressure (BP), large elastic artery stiffness, middle cerebral artery pulsatility index (MCAv PI), and magnetic resonance elastography (MRE), a sensitive measure of HC viscoelasticity. Individuals with higher carotid pulse pressure (PP) exhibited lower HC stiffness (β = -0.39, r = -0.41, p = 0.05), independent of age and sex. Collectively, carotid PP and MCAv PI significantly explained a large portion of the total variance in HC stiffness (adjusted R2 = 0.41, p = 0.005) in the absence of associations with HC volumes. These cross-sectional findings suggest that the earliest reductions in HC tissue properties are associated with alterations in vascular function.
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Affiliation(s)
- Faria Sanjana
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Theodore M DeConne
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Lucy V Hiscox
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Ryan T Pohlig
- Department of Epidemiology, University of Delaware, Newark, DE, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
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16
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Smith DR, Helm CA, Zonnino A, McGarry MD, Johnson CL, Sergi F. Individual Muscle Force Estimation in the Human Forearm Using Multi-Muscle MR Elastography (MM-MRE). IEEE Trans Biomed Eng 2023; 70:3206-3215. [PMID: 37279119 PMCID: PMC10636590 DOI: 10.1109/tbme.2023.3283185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
OBJECTIVE To establish the sensitivity of magnetic resonance elastography (MRE) to active muscle contraction in multiple muscles of the forearm. METHODS We combined MRE of forearm muscles with an MRI-compatible device, the MREbot, to simultaneously measure the mechanical properties of tissues in the forearm and the torque applied by the wrist joint during isometric tasks. We measured shear wave speed of thirteen forearm muscles via MRE in a series of contractile states and wrist postures and fit these outputs to a force estimation algorithm based on a musculoskeletal model. RESULTS Shear wave speed changed significantly upon several factors, including whether the muscle was recruited as an agonist or antagonist (p = 0.0019), torque amplitude (p = <0.0001), and wrist posture (p = 0.0002). Shear wave speed increased significantly during both agonist (p = <0.0001) and antagonist (p = 0.0448) contraction. Additionally, there was a greater increase in shear wave speed at greater levels of loading. The variations due to these factors indicate the sensitivity to functional loading of muscle. Under the assumption of a quadratic relationship between shear wave speed and muscle force, MRE measurements accounted for an average of 70% of the variance in the measured joint torque. CONCLUSION This study shows the ability of MM-MRE to capture variations in individual muscle shear wave speed due to muscle activation and presents a method to estimate individual muscle force through MM-MRE derived measurements of shear wave speed. SIGNIFICANCE MM-MRE could be used to establish normal and abnormal muscle co-contraction patterns in muscles of the forearm controlling hand and wrist function.
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Affiliation(s)
- Daniel R. Smith
- Department of Biomedical Engineering, University of Delaware, Newark DE, 19713
| | - Cody A. Helm
- Department of Biomedical Engineering, University of Delaware, Newark DE, 19713
| | | | | | - Curtis L. Johnson
- Department of Biomedical Engineering, University of Delaware, Newark DE, 19713
| | - Fabrizio Sergi
- Department of Biomedical Engineering, University of Delaware, Newark DE, 19713
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Morrison O, Destrade M, Tripathi BB. An atlas of the heterogeneous viscoelastic brain with local power-law attenuation synthesised using Prony-series. Acta Biomater 2023; 169:66-87. [PMID: 37507033 DOI: 10.1016/j.actbio.2023.07.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/16/2023] [Accepted: 07/24/2023] [Indexed: 07/30/2023]
Abstract
This review addresses the acute need to acknowledge the mechanical heterogeneity of brain matter and to accurately calibrate its local viscoelastic material properties accordingly. Specifically, it is important to compile the existing and disparate literature on attenuation power-laws and dispersion to make progress in wave physics of brain matter, a field of research that has the potential to explain the mechanisms at play in diffuse axonal injury and mild traumatic brain injury in general. Currently, viscous effects in the brain are modelled using Prony-series, i.e., a sum of decaying exponentials at different relaxation times. Here we collect and synthesise the Prony-series coefficients appearing in the literature for twelve regions: brainstem, basal ganglia, cerebellum, corona radiata, corpus callosum, cortex, dentate gyrus, hippocampus, thalamus, grey matter, white matter, homogeneous brain, and for eight different mammals: pig, rat, human, mouse, cow, sheep, monkey and dog. Using this data, we compute the fractional-exponent attenuation power-laws for different tissues of the brain, the corresponding dispersion laws resulting from causality, and the averaged Prony-series coefficients. STATEMENT OF SIGNIFICANCE: Traumatic brain injuries are considered a silent epidemic and finite element methods (FEMs) are used in modelling brain deformation, requiring access to viscoelastic properties of brain. To the best of our knowledge, this work presents 1) the first multi-frequency viscoelastic atlas of the heterogeneous brain, 2) the first review focusing on viscoelastic modelling in both FEMs and experimental works, 3) the first attempt to conglomerate the disparate existing literature on the viscoelastic modelling of the brain and 4) the largest collection of viscoelastic parameters for the brain (212 different Prony-series spanning 12 different tissues and 8 different animal surrogates). Furthermore, this work presents the first brain atlas of attenuation power-laws essential for modelling shear waves in brain.
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Affiliation(s)
- Oisín Morrison
- School of Mathematical and Statistical Sciences, University of Galway, University Road, Galway, Ireland
| | - Michel Destrade
- School of Mathematical and Statistical Sciences, University of Galway, University Road, Galway, Ireland
| | - Bharat B Tripathi
- School of Mathematical and Statistical Sciences, University of Galway, University Road, Galway, Ireland.
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Milbocker KA, Williams LT, Caban-Rivera DA, Smith IF, Kurtz S, McGarry MDJ, Wattrisse B, Van Houten EEW, Johnson CL, Klintsova AY. Monitoring lasting changes to brain tissue integrity through mechanical properties following adolescent exercise intervention in a rat model of Fetal Alcohol Spectrum Disorders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.26.559571. [PMID: 37808633 PMCID: PMC10557734 DOI: 10.1101/2023.09.26.559571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Background Fetal Alcohol Spectrum Disorders (FASD) encompass a group of highly prevalent conditions resulting from prenatal alcohol exposure. Alcohol exposure during the third trimester of pregnancy overlapping with the brain growth spurt is detrimental to white matter growth and myelination, particularly in the corpus callosum, ultimately affecting tissue integrity in adolescence. Traditional neuroimaging techniques have been essential for assessing neurodevelopment in affected youth; however, these methods are limited in their capacity to track subtle microstructural alterations to white matter, thus restricting their effectiveness in monitoring therapeutic intervention. In this preliminary study we use a highly sensitive and clinically translatable Magnetic Resonance Elastography (MRE) protocol for assessing brain tissue microstructure through its mechanical properties following an exercise intervention in a rat model of FASD. Methods Rat pups were divided into two groups: alcohol-exposed (AE) pups which received alcohol in milk substitute (5.25 g/kg/day) via intragastric intubation on postnatal days (PD) four through nine during the rat brain growth spurt (Dobbing and Sands, 1979), or sham-intubated (SI) controls. In adolescence, on PD 30, half AE and SI rats were randomly assigned to either a modified home cage with free access to a running wheel or to a new home cage for 12 days (Gursky and Klintsova, 2017). Previous studies conducted in the lab have shown that 12 days of voluntary exercise intervention in adolescence immediately ameliorated callosal myelination in AE rats (Milbocker et al., 2022, 2023). MRE was used to measure longitudinal changes to mechanical properties of the whole brain and the corpus callosum at intervention termination and one-month post-intervention. Histological quantification of precursor and myelinating oligoglia in corpus callosum was performed one-month post-intervention. Results Prior to intervention, AE rats had lower forebrain stiffness in adolescence compared to SI controls ( p = 0.02). Exercise intervention immediately mitigated this effect in AE rats, resulting in higher forebrain stiffness post-intervention in adolescence. Similarly, we discovered that forebrain damping ratio was lowest in AE rats in adolescence ( p < 0.01), irrespective of intervention exposure. One-month post-intervention in adulthood, AE and SI rats exhibited comparable forebrain stiffness and damping ratio (p > 0.05). Taken together, these MRE data suggest that adolescent exercise intervention supports neurodevelopmental "catch-up" in AE rats. Analysis of the stiffness and damping ratio of the body of corpus callosum revealed that these measures increased with age. Finally, histological quantification of myelinating oligodendrocytes one-month post-intervention revealed a negative rebound effect of exercise cessation on the total estimate of these cells in the body of corpus callosum, irrespective of treatment group which was not convergent with noninvasive MRE measures. Conclusions This is the first application of MRE to measure changes in brain mechanical properties in a rodent model of FASD. MRE successfully captured alcohol-related changes to forebrain stiffness and damping ratio in adolescence. These preliminary findings expand upon results from previous studies which used traditional diffusion neuroimaging to identify structural changes to the adolescent brain in rodent models of FASD (Milbocker et al., 2022; Newville et al., 2017). Additionally, in vivo MRE identified an exercise-related alteration to forebrain stiffness that occurred in adolescence, immediately post-intervention.
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Meyer T, Kreft B, Bergs J, Antes E, Anders MS, Wellge B, Braun J, Doyley M, Tzschätzsch H, Sack I. Stiffness pulsation of the human brain detected by non-invasive time-harmonic elastography. Front Bioeng Biotechnol 2023; 11:1140734. [PMID: 37650041 PMCID: PMC10463728 DOI: 10.3389/fbioe.2023.1140734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 07/19/2023] [Indexed: 09/01/2023] Open
Abstract
Introduction: Cerebral pulsation is a vital aspect of cerebral hemodynamics. Changes in arterial pressure in response to cardiac pulsation cause cerebral pulsation, which is related to cerebrovascular compliance and cerebral blood perfusion. Cerebrovascular compliance and blood perfusion influence the mechanical properties of the brain, causing pulsation-induced changes in cerebral stiffness. However, there is currently no imaging technique available that can directly quantify the pulsation of brain stiffness in real time. Methods: Therefore, we developed non-invasive ultrasound time-harmonic elastography (THE) technique for the real-time detection of brain stiffness pulsation. We used state-of-the-art plane-wave imaging for interleaved acquisitions of shear waves at a frequency of 60 Hz to measure stiffness and color flow imaging to measure cerebral blood flow within the middle cerebral artery. In the second experiment, we used cost-effective lineby-line B-mode imaging to measure the same mechanical parameters without flow imaging to facilitate future translation to the clinic. Results: In 10 healthy volunteers, stiffness increased during the passage of the arterial pulse wave from 4.8% ± 1.8% in the temporal parenchyma to 11% ± 5% in the basal cisterns and 13% ± 9% in the brain stem. Brain stiffness peaked in synchrony with cerebral blood flow at approximately 180 ± 30 ms after the cardiac R-wave. Line-by-line THE provided the same stiffness values with similar time resolution as high-end plane-wave THE, demonstrating the robustness of brain stiffness pulsation as an imaging marker. Discussion: Overall, this study sets the background and provides reference values for time-resolved THE in the human brain as a cost-efficient and easy-touse mechanical biomarker associated with cerebrovascular compliance.
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Affiliation(s)
- Tom Meyer
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Bernhard Kreft
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Judith Bergs
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Erik Antes
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Matthias S. Anders
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Brunhilde Wellge
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité—University Medicine Berlin, Berlin, Germany
| | - Marvin Doyley
- Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, NY, United States
| | - Heiko Tzschätzsch
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
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Joo B, Won SY, Sinkus R, Lee SK. Viscoelastic Property of the Brain Assessed With Magnetic Resonance Elastography and Its Association With Glymphatic System in Neurologically Normal Individuals. Korean J Radiol 2023; 24:564-573. [PMID: 37271210 DOI: 10.3348/kjr.2022.0992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 03/11/2023] [Accepted: 03/27/2023] [Indexed: 06/06/2023] Open
Abstract
OBJECTIVE To investigate the feasibility of assessing the viscoelastic properties of the brain using magnetic resonance elastography (MRE) and a novel MRE transducer to determine the relationship between the viscoelastic properties and glymphatic function in neurologically normal individuals. MATERIALS AND METHODS This prospective study included 47 neurologically normal individuals aged 23-74 years (male-to-female ratio, 21:26). The MRE was acquired using a gravitational transducer based on a rotational eccentric mass as the driving system. The magnitude of the complex shear modulus |G*| and the phase angle ϕ were measured in the centrum semiovale area. To evaluate glymphatic function, the Diffusion Tensor Image Analysis Along the Perivascular Space (DTI-ALPS) method was utilized and the ALPS index was calculated. Univariable and multivariable (variables with P < 0.2 from the univariable analysis) linear regression analyses were performed for |G*| and ϕ and included sex, age, normalized white matter hyperintensity (WMH) volume, brain parenchymal volume, and ALPS index as covariates. RESULTS In the univariable analysis for |G*|, age (P = 0.005), brain parenchymal volume (P = 0.152), normalized WMH volume (P = 0.011), and ALPS index (P = 0.005) were identified as candidates with P < 0.2. In the multivariable analysis, only the ALPS index was independently associated with |G*|, showing a positive relationship (β = 0.300, P = 0.029). For ϕ, normalized WMH volume (P = 0.128) and ALPS index (P = 0.015) were identified as candidates for multivariable analysis, and only the ALPS index was independently associated with ϕ (β = 0.057, P = 0.039). CONCLUSION Brain MRE using a gravitational transducer is feasible in neurologically normal individuals over a wide age range. The significant correlation between the viscoelastic properties of the brain and glymphatic function suggests that a more organized or preserved microenvironment of the brain parenchyma is associated with a more unimpeded glymphatic fluid flow.
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Affiliation(s)
- Bio Joo
- Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - So Yeon Won
- Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ralph Sinkus
- School of Biomedical Imaging and Imaging Sciences, King's College London, London, UK
- INSERM U1148, Laboratory for Vascular Translational Science, University Paris Diderot, Paris, France
| | - Seung-Koo Lee
- Department of Radiology and Research Institute of Radiological Science and Center for Clinical Image Data Science, Yonsei University College of Medicine, Seoul, Korea.
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21
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Hangel G, Schmitz‐Abecassis B, Sollmann N, Pinto J, Arzanforoosh F, Barkhof F, Booth T, Calvo‐Imirizaldu M, Cassia G, Chmelik M, Clement P, Ercan E, Fernández‐Seara MA, Furtner J, Fuster‐Garcia E, Grech‐Sollars M, Guven NT, Hatay GH, Karami G, Keil VC, Kim M, Koekkoek JAF, Kukran S, Mancini L, Nechifor RE, Özcan A, Ozturk‐Isik E, Piskin S, Schmainda KM, Svensson SF, Tseng C, Unnikrishnan S, Vos F, Warnert E, Zhao MY, Jancalek R, Nunes T, Hirschler L, Smits M, Petr J, Emblem KE. Advanced MR Techniques for Preoperative Glioma Characterization: Part 2. J Magn Reson Imaging 2023; 57:1676-1695. [PMID: 36912262 PMCID: PMC10947037 DOI: 10.1002/jmri.28663] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 03/14/2023] Open
Abstract
Preoperative clinical MRI protocols for gliomas, brain tumors with dismal outcomes due to their infiltrative properties, still rely on conventional structural MRI, which does not deliver information on tumor genotype and is limited in the delineation of diffuse gliomas. The GliMR COST action wants to raise awareness about the state of the art of advanced MRI techniques in gliomas and their possible clinical translation. This review describes current methods, limits, and applications of advanced MRI for the preoperative assessment of glioma, summarizing the level of clinical validation of different techniques. In this second part, we review magnetic resonance spectroscopy (MRS), chemical exchange saturation transfer (CEST), susceptibility-weighted imaging (SWI), MRI-PET, MR elastography (MRE), and MR-based radiomics applications. The first part of this review addresses dynamic susceptibility contrast (DSC) and dynamic contrast-enhanced (DCE) MRI, arterial spin labeling (ASL), diffusion-weighted MRI, vessel imaging, and magnetic resonance fingerprinting (MRF). EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Gilbert Hangel
- Department of NeurosurgeryMedical University of ViennaViennaAustria
- High Field MR Centre, Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for MR Imaging BiomarkersViennaAustria
- Medical Imaging ClusterMedical University of ViennaViennaAustria
| | - Bárbara Schmitz‐Abecassis
- Department of RadiologyLeiden University Medical CenterLeidenthe Netherlands
- Medical Delta FoundationDelftthe Netherlands
| | - Nico Sollmann
- Department of Diagnostic and Interventional RadiologyUniversity Hospital UlmUlmGermany
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der IsarTechnical University of MunichMunichGermany
- TUM‐Neuroimaging Center, Klinikum rechts der IsarTechnical University of MunichMunichGermany
| | - Joana Pinto
- Institute of Biomedical Engineering, Department of Engineering ScienceUniversity of OxfordOxfordUK
| | | | - Frederik Barkhof
- Department of Radiology & Nuclear MedicineAmsterdam UMC, Vrije UniversiteitAmsterdamNetherlands
- Queen Square Institute of Neurology and Centre for Medical Image ComputingUniversity College LondonLondonUK
| | - Thomas Booth
- School of Biomedical Engineering and Imaging SciencesKing's College LondonLondonUK
- Department of NeuroradiologyKing's College Hospital NHS Foundation TrustLondonUK
| | | | | | - Marek Chmelik
- Department of Technical Disciplines in Medicine, Faculty of Health CareUniversity of PrešovPrešovSlovakia
| | - Patricia Clement
- Department of Diagnostic SciencesGhent UniversityGhentBelgium
- Department of Medical ImagingGhent University HospitalGhentBelgium
| | - Ece Ercan
- Department of RadiologyLeiden University Medical CenterLeidenthe Netherlands
| | - Maria A. Fernández‐Seara
- Department of RadiologyClínica Universidad de NavarraPamplonaSpain
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
| | - Julia Furtner
- Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
- Research Center of Medical Image Analysis and Artificial IntelligenceDanube Private UniversityAustria
| | - Elies Fuster‐Garcia
- Biomedical Data Science Laboratory, Instituto Universitario de Tecnologías de la Información y ComunicacionesUniversitat Politècnica de ValènciaValenciaSpain
| | - Matthew Grech‐Sollars
- Centre for Medical Image Computing, Department of Computer ScienceUniversity College LondonLondonUK
- Lysholm Department of Neuroradiology, National Hospital for Neurology and NeurosurgeryUniversity College London Hospitals NHS Foundation TrustLondonUK
| | - N. Tugay Guven
- Institute of Biomedical EngineeringBogazici University IstanbulIstanbulTurkey
| | - Gokce Hale Hatay
- Institute of Biomedical EngineeringBogazici University IstanbulIstanbulTurkey
| | - Golestan Karami
- School of Biomedical Engineering and Imaging SciencesKing's College LondonLondonUK
| | - Vera C. Keil
- Department of Radiology & Nuclear MedicineAmsterdam UMC, Vrije UniversiteitAmsterdamNetherlands
- Cancer Center AmsterdamAmsterdamNetherlands
| | - Mina Kim
- Centre for Medical Image Computing, Department of Medical Physics & Biomedical Engineering and Department of NeuroinflammationUniversity College LondonLondonUK
| | - Johan A. F. Koekkoek
- Department of NeurologyLeiden University Medical CenterLeidenthe Netherlands
- Department of NeurologyHaaglanden Medical CenterNetherlands
| | - Simran Kukran
- Department of BioengineeringImperial College LondonLondonUK
- Department of Radiotherapy and ImagingInstitute of Cancer ResearchUK
| | - Laura Mancini
- Lysholm Department of Neuroradiology, National Hospital for Neurology and NeurosurgeryUniversity College London Hospitals NHS Foundation TrustLondonUK
- Department of Brain Repair and Rehabilitation, Institute of NeurologyUniversity College LondonLondonUK
| | - Ruben Emanuel Nechifor
- Department of Clinical Psychology and Psychotherapy, International Institute for the Advanced Studies of Psychotherapy and Applied Mental HealthBabes‐Bolyai UniversityRomania
| | - Alpay Özcan
- Electrical and Electronics Engineering DepartmentBogazici University IstanbulIstanbulTurkey
| | - Esin Ozturk‐Isik
- Institute of Biomedical EngineeringBogazici University IstanbulIstanbulTurkey
| | - Senol Piskin
- Department of Mechanical Engineering, Faculty of Natural Sciences and EngineeringIstinye University IstanbulIstanbulTurkey
| | | | - Siri F. Svensson
- Department of Physics and Computational RadiologyOslo University HospitalOsloNorway
- Department of PhysicsUniversity of OsloOsloNorway
| | - Chih‐Hsien Tseng
- Medical Delta FoundationDelftthe Netherlands
- Department of Imaging PhysicsDelft University of TechnologyDelftthe Netherlands
| | - Saritha Unnikrishnan
- Faculty of Engineering and DesignAtlantic Technological University (ATU) SligoSligoIreland
- Mathematical Modelling and Intelligent Systems for Health and Environment (MISHE), ATU SligoSligoIreland
| | - Frans Vos
- Medical Delta FoundationDelftthe Netherlands
- Department of Radiology & Nuclear MedicineErasmus MCRotterdamNetherlands
- Department of Imaging PhysicsDelft University of TechnologyDelftthe Netherlands
| | - Esther Warnert
- Department of Radiology & Nuclear MedicineErasmus MCRotterdamNetherlands
| | - Moss Y. Zhao
- Department of RadiologyStanford UniversityStanfordCaliforniaUSA
- Stanford Cardiovascular InstituteStanford UniversityStanfordCaliforniaUSA
| | - Radim Jancalek
- Department of NeurosurgerySt. Anne's University HospitalBrnoCzechia
- Faculty of MedicineMasaryk UniversityBrnoCzechia
| | - Teresa Nunes
- Department of NeuroradiologyHospital Garcia de OrtaAlmadaPortugal
| | - Lydiane Hirschler
- C.J. Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenthe Netherlands
| | - Marion Smits
- Medical Delta FoundationDelftthe Netherlands
- Department of Radiology & Nuclear MedicineErasmus MCRotterdamNetherlands
- Brain Tumour CentreErasmus MC Cancer InstituteRotterdamthe Netherlands
| | - Jan Petr
- Helmholtz‐Zentrum Dresden‐RossendorfInstitute of Radiopharmaceutical Cancer ResearchDresdenGermany
| | - Kyrre E. Emblem
- Department of Physics and Computational RadiologyOslo University HospitalOsloNorway
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22
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Jyoti D, McGarry M, Caban-Rivera DA, Van Houten E, Johnson CL, Paulsen K. Transversely-isotropic brain in vivo MR elastography with anisotropic damping. J Mech Behav Biomed Mater 2023; 141:105744. [PMID: 36893687 PMCID: PMC10084917 DOI: 10.1016/j.jmbbm.2023.105744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/17/2023] [Accepted: 02/26/2023] [Indexed: 03/05/2023]
Abstract
Measuring tissue parameters from increasingly sophisticated mechanical property models may uncover new contrast mechanisms with clinical utility. Building on previous work on in vivo brain MR elastography (MRE) with a transversely-isotropic with isotropic damping (TI-ID) model, we explore a new transversely-isotropic with anisotropic damping (TI-AD) model that involves six independent parameters describing direction-dependent behavior for both stiffness and damping. The direction of mechanical anisotropy is determined by diffusion tensor imaging and we fit three complex-valued moduli distributions across the full brain volume to minimize differences between measured and modeled displacements. We demonstrate spatially accurate property reconstruction in an idealized shell phantom simulation, as well as an ensemble of 20 realistic, randomly-generated simulated brains. We characterize the simulated precisions of all six parameters across major white matter tracts to be high, suggesting that they can be measured independently with acceptable accuracy from MRE data. Finally, we present in vivo anisotropic damping MRE reconstruction data. We perform t-tests on eight repeated MRE brain exams on a single-subject, and find that the three damping parameters are statistically distinct for most tracts, lobes and the whole brain. We also show that population variations in a 17-subject cohort exceed single-subject measurement repeatability for most tracts, lobes and whole brain, for all six parameters. These results suggest that the TI-AD model offers new information that may support differential diagnosis of brain diseases.
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Affiliation(s)
- Dhrubo Jyoti
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
| | - Matthew McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
| | | | | | | | - Keith Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA; Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA
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23
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Ge GR, Rolland JP, Song W, Nedergaard M, Parker KJ. Fluid compartments influence elastography of the aging mouse brain. Phys Med Biol 2023; 68:095004. [PMID: 36996842 PMCID: PMC10108361 DOI: 10.1088/1361-6560/acc922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/30/2023] [Indexed: 04/01/2023]
Abstract
Objective. Elastography of the brain has the potential to reveal subtle but clinically important changes in the structure and composition as a function of age, disease, and injury.Approach. In order to quantify the specific effects of aging on mouse brain elastography, and to determine the key factors influencing observed changes, we applied optical coherence tomography reverberant shear wave elastography at 2000 Hz to a group of wild-type healthy mice ranging from young to old age.Main results. We found a strong trend towards increasing stiffness with age, with an approximately 30% increase in shear wave speed from 2 months to 30 months within this sampled group. Furthermore, this appears to be strongly correlated with decreasing measures of whole brain fluid content, so older brains have less water and are stiffer. Rheological models are applied, and the strong effect is captured by specific assignment of changes to the glymphatic compartment of the brain fluid structures along with a correlated change in the parenchymal stiffness.Significance. Short-term and longer-term changes in elastography measures may provide a sensitive biomarker of progressive and fine-scale changes in the glymphatic fluid channels and parenchymal components of the brain.
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Affiliation(s)
- Gary R Ge
- Institute of Optics, University of Rochester, 480 Intercampus Drive, Box 270186, Rochester, NY 14627, United States of America
| | - Jannick P Rolland
- Institute of Optics, University of Rochester, 480 Intercampus Drive, Box 270186, Rochester, NY 14627, United States of America
| | - Wei Song
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, United States of America
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, United States of America
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, 724 Computer Studies Building, Box 270231, Rochester, NY 14627, United States of America
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24
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Effects of stress-dependent growth on evolution of sulcal direction and curvature in models of cortical folding. BRAIN MULTIPHYSICS 2023. [DOI: 10.1016/j.brain.2023.100065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
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25
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Kabir IE, Caban-Rivera DA, Ormachea J, Parker KJ, Johnson CL, Doyley MM. Reverberant magnetic resonance elastographic imaging using a single mechanical driver. Phys Med Biol 2023; 68:055015. [PMID: 36780698 PMCID: PMC9969521 DOI: 10.1088/1361-6560/acbbb7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 02/13/2023] [Indexed: 02/15/2023]
Abstract
Reverberant elastography provides fast and robust estimates of shear modulus; however, its reliance on multiple mechanical drivers hampers clinical utility. In this work, we hypothesize that for constrained organs such as the brain, reverberant elastography can produce accurate magnetic resonance elastograms with a single mechanical driver. To corroborate this hypothesis, we performed studies on healthy volunteers (n= 3); and a constrained calibrated brain phantom containing spherical inclusions with diameters ranging from 4-18 mm. In both studies (i.e. phantom and clinical), imaging was performed at frequencies of 50 and 70 Hz. We used the accuracy and contrast-to-noise ratio performance metrics to evaluate reverberant elastograms relative to those computed using the established subzone inversion method. Errors incurred in reverberant elastograms varied from 1.3% to 16.6% when imaging at 50 Hz and 3.1% and 16.8% when imaging at 70 Hz. In contrast, errors incurred in subzone elastograms ranged from 1.9% to 13% at 50 Hz and 3.6% to 14.9% at 70 Hz. The contrast-to-noise ratio of reverberant elastograms ranged from 63.1 to 73 dB compared to 65 to 66.2 dB for subzone elastograms. The average global brain shear modulus estimated from reverberant and subzone elastograms was 2.36 ± 0.07 kPa and 2.38 ± 0.11 kPa, respectively, when imaging at 50 Hz and 2.70 ± 0.20 kPa and 2.89 ± 0.60 kPa respectively, when imaging at 70 Hz. The results of this investigation demonstrate that reverberant elastography can produce accurate, high-quality elastograms of the brain with a single mechanical driver.
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Affiliation(s)
- Irteza Enan Kabir
- University of Rochester, Hajim School of Engineering and Applied Sciences 1467, Rochester, NY, United States of America
| | - Diego A Caban-Rivera
- University of Delaware, Department of Biomedical Engineering 19716, Newark, DE, United States of America
| | - Juvenal Ormachea
- Verasonics, Inc., 11335 NE 122nd Way, Suite 100 98034 Kirkland, WA, United States of America
| | - Kevin J Parker
- University of Rochester, Hajim School of Engineering and Applied Sciences 1467, Rochester, NY, United States of America
| | - Curtis L Johnson
- University of Delaware, Department of Biomedical Engineering 19716, Newark, DE, United States of America
| | - Marvin M Doyley
- University of Rochester, Hajim School of Engineering and Applied Sciences 1467, Rochester, NY, United States of America
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26
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Smith DR, Caban-Rivera DA, Williams LT, Van Houten EE, Bayly PV, Paulsen KD, McGarry MD, Johnson CL. In vivoestimation of anisotropic mechanical properties of the gastrocnemius during functional loading with MR elastography. Phys Med Biol 2023; 68:10.1088/1361-6560/acb482. [PMID: 36652716 PMCID: PMC9943592 DOI: 10.1088/1361-6560/acb482] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/18/2023] [Indexed: 01/20/2023]
Abstract
Objective.In vivoimaging assessments of skeletal muscle structure and function allow for longitudinal quantification of tissue health. Magnetic resonance elastography (MRE) non-invasively quantifies tissue mechanical properties, allowing for evaluation of skeletal muscle biomechanics in response to loading, creating a better understanding of muscle functional health.Approach. In this study, we analyze the anisotropic mechanical response of calf muscles using MRE with a transversely isotropic, nonlinear inversion algorithm (TI-NLI) to investigate the role of muscle fiber stiffening under load. We estimate anisotropic material parameters including fiber shear stiffness (μ1), substrate shear stiffness (μ2), shear anisotropy (ϕ), and tensile anisotropy (ζ) of the gastrocnemius muscle in response to both passive and active tension.Main results. In passive tension, we found a significant increase inμ1,ϕ,andζwith increasing muscle length. While in active tension, we observed increasingμ2and decreasingϕandζduring active dorsiflexion and plantarflexion-indicating less anisotropy-with greater effects when the muscles act as agonist.Significance. The study demonstrates the ability of this anisotropic MRE method to capture the multifaceted mechanical response of skeletal muscle to tissue loading from muscle lengthening and contraction.
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Affiliation(s)
- Daniel R. Smith
- Department of Biomedical Engineering, University of Delaware, Newark DE, 19711
- Department of Orthopaedics, Emory University School of Medicine, Atlanta GA, 30307
- Emory Sports Performance and Research Center, Flowery Branch GA, 30542
| | | | - L. Tyler Williams
- Department of Biomedical Engineering, University of Delaware, Newark DE, 19711
| | | | - Phil V. Bayly
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis MO
| | - Keith D. Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755
- Dartmouth-Hitchcock Medical Center, Lebanon NH, 03756
| | | | - Curtis L. Johnson
- Department of Biomedical Engineering, University of Delaware, Newark DE, 19711
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27
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Knutsen AK, Vidhate S, McIlvain G, Luster J, Galindo EJ, Johnson CL, Pham DL, Butman JA, Mejia-Alvarez R, Tartis M, Willis AM. Characterization of material properties and deformation in the ANGUS phantom during mild head impacts using MRI. J Mech Behav Biomed Mater 2023; 138:105586. [PMID: 36516544 PMCID: PMC10169236 DOI: 10.1016/j.jmbbm.2022.105586] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/26/2022] [Accepted: 11/19/2022] [Indexed: 12/12/2022]
Abstract
Traumatic brain injury (TBI) is a major health concern affecting both military and civilian populations. Despite notable advances in TBI research in recent years, there remains a significant gap in linking the impulsive loadings from a blast or a blunt impact to the clinical injury patterns observed in TBI. Synthetic head models or phantoms can be used to establish this link as they can be constructed with geometry, anatomy, and material properties that match the human brain, and can be used as an alternative to animal models. This study presents one such phantom called the Anthropomorphic Neurologic Gyrencephalic Unified Standard (ANGUS) phantom, which is an idealized gyrencephalic brain phantom composed of polyacrylamide gel. Here we mechanically characterized the ANGUS phantom using tagged magnetic resonance imaging (MRI) and magnetic resonance elastography (MRE), and then compared the outcomes to data obtained in healthy volunteers. The direct comparison between the phantom's response and the data from a cohort of in vivo human subjects demonstrate that the ANGUS phantom may be an appropriate model for bulk tissue response and gyral dynamics of the human brain under small amplitude linear impulses. However, the phantom's response differs from that of the in vivo human brain under rotational impacts, suggesting avenues for future improvements to the phantom.
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Affiliation(s)
- Andrew K Knutsen
- Center for Neuroscience and Regenerative Medicine, The Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, 20814, USA
| | - Suhas Vidhate
- Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Josh Luster
- Department of Neurology, Brooke Army Medical Center, Fort Sam Houston, TX, 78234, USA
| | - Eric J Galindo
- Department of Chemical Engineering, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Dzung L Pham
- Center for Neuroscience and Regenerative Medicine, The Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, 20814, USA
| | - John A Butman
- Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ricardo Mejia-Alvarez
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, 48824, USA
| | - Michaelann Tartis
- Department of Chemical Engineering, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA
| | - Adam M Willis
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, 48824, USA; 59th Medical Wing, Office of the Chief Scientist, Lackland AFB, TX, 78236, USA
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28
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Bertalan G, Becker J, Tzschätzsch H, Morr A, Herthum H, Shahryari M, Greenhalgh RD, Guo J, Schröder L, Alzheimer C, Budday S, Franze K, Braun J, Sack I. Mechanical behavior of the hippocampus and corpus callosum: An attempt to reconcile ex vivo with in vivo and micro with macro properties. J Mech Behav Biomed Mater 2023; 138:105613. [PMID: 36549250 DOI: 10.1016/j.jmbbm.2022.105613] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 11/24/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
Mechanical properties of brain tissue are very complex and vary with the species, region, method, and dynamic range, and between in vivo and ex vivo measurements. To reconcile this variability, we investigated in vivo and ex vivo stiffness properties of two distinct regions in the human and mouse brain - the hippocampus (HP) and the corpus callosum (CC) - using different methods. Under quasi-static conditions, we examined ex vivo murine HP and CC by atomic force microscopy (AFM). Between 16 and 40Hz, we investigated the in vivo brains of healthy volunteers by magnetic resonance elastography (MRE) in a 3-T clinical scanner. At high-frequency stimulation between 1000 and 1400Hz, we investigated the murine HP and CC ex vivo and in vivo with MRE in a 7-T preclinical system. HP and CC showed pronounced stiffness dispersion, as reflected by a factor of 32-36 increase in shear modulus from AFM to low-frequency human MRE and a 25-fold higher shear wave velocity in murine MRE than in human MRE. At low frequencies, HP was softer than CC, in both ex vivo mouse specimens (p < 0.05) and in vivo human brains (p < 0.01) while, at high frequencies, CC was softer than HP under in vivo (p < 0.01) and ex vivo (p < 0.05) conditions. The standard linear solid model comprising three elements reproduced the observed HP and CC stiffness dispersions, while other two- and three-element models failed. Our results indicate a remarkable consistency of brain stiffness across species, ex vivo and in vivo states, and different measurement techniques when marked viscoelastic dispersion properties combining equilibrium and non-equilibrium mechanical elements are considered.
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Affiliation(s)
- Gergerly Bertalan
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Julia Becker
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Heiko Tzschätzsch
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Anna Morr
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Helge Herthum
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Mehrgan Shahryari
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ryan D Greenhalgh
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Leif Schröder
- Translational Molecular Imaging, Deutsches Krebsforschungszentrum, Heidelberg, Germany
| | - Christian Alzheimer
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Silvia Budday
- Institute of Applied Mechanics, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; Institute of Medical Physics, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Erlangen, Germany; Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
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Yazdani N, Willits RK. Mimicking the neural stem cell niche: An engineer’s view of cell: material interactions. FRONTIERS IN CHEMICAL ENGINEERING 2023. [DOI: 10.3389/fceng.2022.1086099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Neural stem cells have attracted attention in recent years to treat neurodegeneration. There are two neurogenic regions in the brain where neural stem cells reside, one of which is called the subventricular zone (SVZ). The SVZ niche is a complicated microenvironment providing cues to regulate self-renewal and differentiation while maintaining the neural stem cell’s pool. Many scientists have spent years understanding the cellular and structural characteristics of the SVZ niche, both in homeostasis and pathological conditions. On the other hand, engineers focus primarily on designing platforms using the knowledge they acquire to understand the effect of individual factors on neural stem cell fate decisions. This review provides a general overview of what we know about the components of the SVZ niche, including the residing cells, extracellular matrix (ECM), growth factors, their interactions, and SVZ niche changes during aging and neurodegenerative diseases. Furthermore, an overview will be given on the biomaterials used to mimic neurogenic niche microenvironments and the design considerations applied to add bioactivity while meeting the structural requirements. Finally, it will discuss the potential gaps in mimicking the microenvironment.
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Yang H, Li H, Liao J, Yuan X, Shi C, Liang W. Compression Elastography and Shear Wave Ultrasound Elastography for Measurement of Brain Elasticity in Full-Term and Premature Neonates: A Prospective Study. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2023; 42:221-231. [PMID: 35929079 DOI: 10.1002/jum.16075] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
OBJECTIVES To investigate the brain tissue elasticity in normal term and premature neonates using compression elastography and shear wave elastography. METHODS This prospective observational study enrolled term and premature neonates admitted to the Third Affiliated Hospital of Guangzhou Medical University between July 2019 and December 2020. RESULTS A total of 106 neonates, including 65 premature neonates and 41 term neonates, were enrolled. The elastic modulus of the frontal white matter in males was significantly lower than in females (11.67 ± 0.98 versus 12.25 ± 1.31, P = .030), but the shear wave velocity of the thalamus in males was significantly lower than in females (1.18 ± 0.13 versus 1.82 ± 0.10, P < .001). There was no significant correlation between real-time body weight and brain tissue elasticity including elastic modulus and shear wave velocity. But, the shear wave velocity of parietal white matter (r = 0.319, P = .014) and thalamus (r = -0.268, P = .040) and the elastic modulus of parietal white matter (r = 0.356, P = .006) were correlated with corrected gestational age. CONCLUSIONS Clinicians may consider using elastography to determine brain tissue elasticity in term and preterm neonates.
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Affiliation(s)
- Huihui Yang
- Department of Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangdong, China
- Department of Ultrasound Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangdong, China
| | - Huibing Li
- Department of Neurosurgery, Guangdong 999 Brain Hospital, Guangdong, China
| | - Jianyi Liao
- Department of Ultrasound Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangdong, China
| | - Xiaoyan Yuan
- Department of Ultrasound Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangdong, China
| | - Changzheng Shi
- Department of Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangdong, China
| | - Weixiang Liang
- Department of Ultrasound Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangdong, China
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Delgorio PL, Hiscox LV, McIlvain G, Kramer MK, Diano AM, Twohy KE, Merritt AA, McGarry MDJ, Schwarb H, Daugherty AM, Ellison JM, Lanzi AM, Cohen ML, Martens CR, Johnson CL. Hippocampal subfield viscoelasticity in amnestic mild cognitive impairment evaluated with MR elastography. Neuroimage Clin 2023; 37:103327. [PMID: 36682312 PMCID: PMC9871742 DOI: 10.1016/j.nicl.2023.103327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/06/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Hippocampal subfields (HCsf) are brain regions important for memory function that are vulnerable to decline with amnestic mild cognitive impairment (aMCI), which is often a preclinical stage of Alzheimer's disease. Studies in aMCI patients often assess HCsf tissue integrity using measures of volume, which has little specificity to microstructure and pathology. We use magnetic resonance elastography (MRE) to examine the viscoelastic mechanical properties of HCsf tissue, which is related to structural integrity, and sensitively detect differences in older adults with aMCI compared to an age-matched control group. Group comparisons revealed HCsf viscoelasticity is differentially affected in aMCI, with CA1-CA2 and DG-CA3 exhibiting lower stiffness and CA1-CA2 exhibiting higher damping ratio, both indicating poorer tissue integrity in aMCI. Including HCsf stiffness in a logistic regression improves classification of aMCI beyond measures of volume alone. Additionally, lower DG-CA3 stiffness predicted aMCI status regardless of DG-CA3 volume. These findings showcase the benefit of using MRE in detecting subtle pathological tissue changes in individuals with aMCI via the HCsf particularly affected in the disease.
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Affiliation(s)
- Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Mary K Kramer
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Alexa M Diano
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Kyra E Twohy
- Department of Mechanical Engineering, University of Delaware, Newark, DE, United States
| | - Alexis A Merritt
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | | | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Ana M Daugherty
- Department of Psychology and Institute of Gerontology, Wayne State University, Detroit, MI, United States
| | - James M Ellison
- Swank Memory Care and Geriatric Consultation, ChristianaCare, Wilmington, DE, United States; Department of Communication Sciences and Disorders, University of Delaware, Newark, DE, United States
| | - Alyssa M Lanzi
- Department of Communication Sciences and Disorders, University of Delaware, Newark, DE, United States
| | - Matthew L Cohen
- Department of Communication Sciences and Disorders, University of Delaware, Newark, DE, United States
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States; Department of Mechanical Engineering, University of Delaware, Newark, DE, United States.
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Herthum H, Hetzer S, Kreft B, Tzschätzsch H, Shahryari M, Meyer T, Görner S, Neubauer H, Guo J, Braun J, Sack I. Cerebral tomoelastography based on multifrequency MR elastography in two and three dimensions. Front Bioeng Biotechnol 2022; 10:1056131. [PMID: 36532573 PMCID: PMC9755504 DOI: 10.3389/fbioe.2022.1056131] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/21/2022] [Indexed: 09/01/2023] Open
Abstract
Purpose: Magnetic resonance elastography (MRE) generates quantitative maps of the mechanical properties of biological soft tissues. However, published values obtained by brain MRE vary largely and lack detail resolution, due to either true biological effects or technical challenges. We here introduce cerebral tomoelastography in two and three dimensions for improved data consistency and detail resolution while considering aging, brain parenchymal fraction (BPF), systolic blood pressure, and body mass index (BMI). Methods: Multifrequency MRE with 2D- and 3D-tomoelastography postprocessing was applied to the brains of 31 volunteers (age range: 22-61 years) for analyzing the coefficient of variation (CV) and effects of biological factors. Eleven volunteers were rescanned after 1 day and 1 year to determine intraclass correlation coefficient (ICC) and identify possible long-term changes. Results: White matter shear wave speed (SWS) was slightly higher in 2D-MRE (1.28 ± 0.02 m/s) than 3D-MRE (1.22 ± 0.05 m/s, p < 0.0001), with less variation after 1 day in 2D (0.33 ± 0.32%) than in 3D (0.96 ± 0.66%, p = 0.004), which was also reflected in a slightly lower CV and higher ICC in 2D (1.84%, 0.97 [0.88-0.99]) than in 3D (3.89%, 0.95 [0.76-0.99]). Remarkably, 3D-MRE was sensitive to a decrease in white matter SWS within only 1 year, whereas no change in white matter volume was observed during this follow-up period. Across volunteers, stiffness correlated with age and BPF, but not with blood pressure and BMI. Conclusion: Cerebral tomoelastography provides high-resolution viscoelasticity maps with excellent consistency. Brain MRE in 2D shows less variation across volunteers in shorter scan times than 3D-MRE, while 3D-MRE appears to be more sensitive to subtle biological effects such as aging.
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Affiliation(s)
- Helge Herthum
- Berlin Center for Advanced Neuroimaging, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
- Institute of Medical Informatics, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Stefan Hetzer
- Berlin Center for Advanced Neuroimaging, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Bernhard Kreft
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Mehrgan Shahryari
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tom Meyer
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Steffen Görner
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Hennes Neubauer
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jing Guo
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Berlin, Germany
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Iglesias M, McGrath DM, Tretyakov MV, Francis ST. Ensemble Kalman inversion for magnetic resonance elastography. Phys Med Biol 2022; 67. [PMID: 36322986 DOI: 10.1088/1361-6560/ac9fa1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 11/01/2022] [Indexed: 11/29/2022]
Abstract
Magnetic resonance elastography (MRE) is an MRI-based diagnostic method for measuring mechanical properties of biological tissues. MRE measurements are processed by an inversion algorithm to produce a map of the biomechanical properties. In this paper a new and powerful method (ensemble Kalman inversion with level sets (EKI)) of MRE inversion is proposed and tested. The method has critical advantages: material property variation at disease boundaries can be accurately identified, and uncertainty of the reconstructed material properties can be evaluated by consequence of the probabilistic nature of the method. EKI is tested in 2D and 3D experiments with synthetic MRE data of the human kidney. It is demonstrated that the proposed inversion method is accurate and fast.
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Affiliation(s)
- Marco Iglesias
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Deirdre M McGrath
- NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, United Kingdom
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom
| | - M V Tretyakov
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Susan T Francis
- NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, United Kingdom
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom
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34
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Ge GR, Song W, Nedergaard M, Rolland JP, Parker KJ. Theory of sleep/wake cycles affecting brain elastography. Phys Med Biol 2022; 67:10.1088/1361-6560/ac9e40. [PMID: 36317278 PMCID: PMC9999375 DOI: 10.1088/1361-6560/ac9e40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/27/2022] [Indexed: 11/05/2022]
Abstract
As elastography of the brain finds increasing clinical applications, fundamental questions remain about baseline viscoelastic properties of the brainin vivo. Furthermore, the underlying mechanisms of how and why elastographic measures can change over time are still not well understood. To study these issues, reverberant shear wave elastography using an optical coherence tomography scanner is implemented on a mouse model, both under awake conditions and in a sleep state where there are known changes in the glymphatic fluid flow system in the brain. We find that shear wave speed, a measure of stiffness, changes by approximately 12% between the two states, sleep versus awake, in the entire cortical brain imaging volume. Our microchannel flow model of biphasic (fluid plus solid) tissue provides a plausible rheological model based on the fractal branching vascular and perivascular system, plus a second parallel system representing the finer scale glymphatic fluid microchannels. By adjusting the glymphatic system fluid volume proportional to the known sleep/wake changes, we are able to approximately predict the measured shear wave speeds and their change with the state of the glymphatic system. The advantages of this model are that its main parameters are derived from anatomical measures and are linked to other major derivations of branching fluid structures including Murray's Law. The implications for clinical studies are that elastography of the brain is strongly influenced by the regulation or dysregulation of the vascular, perivascular, and glymphatic systems.
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Affiliation(s)
- Gary R Ge
- Institute of Optics, University of Rochester, 480 Intercampus Drive, Box 270186, Rochester, NY 14627, United States of America
| | - Wei Song
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, United States of America
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, United States of America
| | - Jannick P Rolland
- Institute of Optics, University of Rochester, 480 Intercampus Drive, Box 270186, Rochester, NY 14627, United States of America
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, 724 Computer Studies Building, Box 270231, Rochester, NY 14627, United States of America
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Torres-Ortega PV, Del Campo-Montoya R, Plano D, Paredes J, Aldazabal J, Luquin MR, Santamaría E, Sanmartín C, Blanco-Prieto MJ, Garbayo E. Encapsulation of MSCs and GDNF in an Injectable Nanoreinforced Supramolecular Hydrogel for Brain Tissue Engineering. Biomacromolecules 2022; 23:4629-4644. [DOI: 10.1021/acs.biomac.2c00853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Pablo Vicente Torres-Ortega
- Department of Pharmaceutical Technology and Chemistry, Faculty of Pharmacy and Nutrition, University of Navarra, C/Irunlarrea 1, 31008Pamplona, Spain
- Navarra Institute for Health Research, IdiSNA, C/Irunlarrea 3, 31008Pamplona, Spain
| | - Rubén Del Campo-Montoya
- Department of Pharmaceutical Technology and Chemistry, Faculty of Pharmacy and Nutrition, University of Navarra, C/Irunlarrea 1, 31008Pamplona, Spain
- Navarra Institute for Health Research, IdiSNA, C/Irunlarrea 3, 31008Pamplona, Spain
| | - Daniel Plano
- Department of Pharmaceutical Technology and Chemistry, Faculty of Pharmacy and Nutrition, University of Navarra, C/Irunlarrea 1, 31008Pamplona, Spain
- Navarra Institute for Health Research, IdiSNA, C/Irunlarrea 3, 31008Pamplona, Spain
| | - Jacobo Paredes
- Tecnun, School of Engineering, University of Navarra, C/Manuel de Lardizábal 15, 20018San Sebastián, Spain
| | - Javier Aldazabal
- Tecnun, School of Engineering, University of Navarra, C/Manuel de Lardizábal 15, 20018San Sebastián, Spain
| | - María-Rosario Luquin
- Navarra Institute for Health Research, IdiSNA, C/Irunlarrea 3, 31008Pamplona, Spain
- Department of Neurology and Neurosciences, Clínica Universidad de Navarra, Pamplona, C/Pío XII 36, 31008Pamplona, Spain
| | - Enrique Santamaría
- Clinical Neuroproteomics Unit, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), Instituto de Investigación Sanitaria de Navarra (IdisNa), 31008Pamplona, Spain
| | - Carmen Sanmartín
- Department of Pharmaceutical Technology and Chemistry, Faculty of Pharmacy and Nutrition, University of Navarra, C/Irunlarrea 1, 31008Pamplona, Spain
- Navarra Institute for Health Research, IdiSNA, C/Irunlarrea 3, 31008Pamplona, Spain
| | - María J. Blanco-Prieto
- Department of Pharmaceutical Technology and Chemistry, Faculty of Pharmacy and Nutrition, University of Navarra, C/Irunlarrea 1, 31008Pamplona, Spain
- Navarra Institute for Health Research, IdiSNA, C/Irunlarrea 3, 31008Pamplona, Spain
| | - Elisa Garbayo
- Department of Pharmaceutical Technology and Chemistry, Faculty of Pharmacy and Nutrition, University of Navarra, C/Irunlarrea 1, 31008Pamplona, Spain
- Navarra Institute for Health Research, IdiSNA, C/Irunlarrea 3, 31008Pamplona, Spain
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Delgorio PL, Hiscox LV, Daugherty AM, Sanjana F, McIlvain G, Pohlig RT, McGarry MDJ, Martens CR, Schwarb H, Johnson CL. Structure-Function Dissociations of Human Hippocampal Subfield Stiffness and Memory Performance. J Neurosci 2022; 42:7957-7968. [PMID: 36261271 PMCID: PMC9617610 DOI: 10.1523/jneurosci.0592-22.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022] Open
Abstract
Aging and neurodegenerative diseases lead to decline in thinking and memory ability. The subfields of the hippocampus (HCsf) play important roles in memory formation and recall. Imaging techniques sensitive to the underlying HCsf tissue microstructure can reveal unique structure-function associations and their vulnerability in aging and disease. The goal of this study was to use magnetic resonance elastography (MRE), a noninvasive MR imaging-based technique that can quantitatively image the viscoelastic mechanical properties of tissue to determine the associations of HCsf stiffness with different cognitive domains across the lifespan. Eighty-eight adult participants completed the study (age 23-81 years, male/female 36/51), in which we aimed to determine which HCsf regions most strongly correlated with different memory performance outcomes and if viscoelasticity of specific HCsf regions mediated the relationship between age and performance. Our results revealed that both interference cost on a verbal memory task and relational memory task performance were significantly related to cornu ammonis 1-2 (CA1-CA2) stiffness (p = 0.018 and p = 0.011, respectively), with CA1-CA2 stiffness significantly mediating the relationship between age and interference cost performance (p = 0.031). There were also significant associations between delayed free verbal recall performance and stiffness of both the dentate gyrus-cornu ammonis 3 (DG-CA3; p = 0.016) and subiculum (SUB; p = 0.032) regions. This further exemplifies the functional specialization of HCsf in declarative memory and the potential use of MRE measures as clinical biomarkers in assessing brain health in aging and disease.SIGNIFICANCE STATEMENT Hippocampal subfields are cytoarchitecturally unique structures involved in distinct aspects of memory processing. Magnetic resonance elastography is a technique that can noninvasively image tissue viscoelastic mechanical properties, potentially serving as sensitive biomarkers of aging and neurodegeneration related to functional outcomes. High-resolution in vivo imaging has invigorated interest in determining subfield functional specialization and their differential vulnerability in aging and disease. Applying MRE to probe subfield-specific cognitive correlates will indicate that measures of subfield stiffness can determine the integrity of structures supporting specific domains of memory performance. These findings will further validate our high-resolution MRE method and support the potential use of subfield stiffness measures as clinical biomarkers in classifying aging and disease states.
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Affiliation(s)
- Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
| | - Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
| | - Ana M Daugherty
- Department of Psychology and Institute of Gerontology, Wayne State University, Detroit, Michigan 48202
| | - Faria Sanjana
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware 19713
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
| | - Ryan T Pohlig
- Biostatistics Core Facility, College of Health Sciences, University of Delaware, Newark, Delaware 19713
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware 19713
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
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Del Campo-Montoya R, Luquin MR, Puerta E, Garbayo E, Blanco-Prieto M. Hydrogels for Brain Repair: Application to Parkinson's Disease. Expert Opin Drug Deliv 2022; 19:1521-1537. [PMID: 36240170 DOI: 10.1080/17425247.2022.2136161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Parkinson's disease is the second most common neurodegenerative disease. Currently, there are no curative therapies, with only symptomatic treatment available. One of the principal reasons for the lack of treatments is the problem of delivering drugs to the brain, mainly due to the blood-brain barrier. Hydrogels are presented as ideal platforms for delivering treatments to the brain ranging from small molecules to cell replacement therapies. AREAS COVERED The potential application of hydrogel-based therapies for Parkinson's disease is addressed. The desirable composition and mechanical properties of these therapies for brain application are discussed, alongside the preclinical research available with hydrogels in Parkinson's disease. Lastly, translational and manufacturing challenges are presented. EXPERT OPINION Parkinson's disease urgently needs novel therapies to delay its progression and for advanced stages, at which conventional therapies fail to control motor symptoms. Neurotrophic factor-loaded hydrogels with stem cells offer one of the most promising therapies. This approach may increase the striatal dopamine content while protecting and promoting the differentiation of stem cells although the generation of synapses between engrafted and host cells remains an issue to overcome. Other challenges to consider are related to the route of administration of hydrogels and their large-scale production, required to accelerate their translation toward the clinic.
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Affiliation(s)
| | | | | | - E Garbayo
- University of navarra, pamplona, 31008 spain
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38
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Shao X, Liu Z, Mao S, Han L. Unraveling the Mechanobiology Underlying Traumatic Brain Injury with Advanced Technologies and Biomaterials. Adv Healthc Mater 2022; 11:e2200760. [PMID: 35841392 DOI: 10.1002/adhm.202200760] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/27/2022] [Indexed: 01/27/2023]
Abstract
Traumatic brain injury (TBI) is a worldwide health and socioeconomic problem, associated with prolonged and complex neurological aftermaths, including a variety of functional deficits and neurodegenerative disorders. Research on the long-term effects has highlighted that TBI shall be regarded as a chronic health condition. The initiation and exacerbation of TBI involve a series of mechanical stimulations and perturbations, accompanied by mechanotransduction events within the brain tissues. Mechanobiology thus offers a unique perspective and likely promising approach to unravel the underlying molecular and biochemical mechanisms leading to neural cells dysfunction after TBI, which may contribute to the discovery of novel targets for future clinical treatment. This article investigates TBI and the subsequent brain dysfunction from a lens of neuromechanobiology. Following an introduction, the mechanobiological insights are examined into the molecular pathology of TBI, and then an overview is given of the latest research technologies to explore neuromechanobiology, with particular focus on microfluidics and biomaterials. Challenges and prospects in the current field are also discussed. Through this article, it is hoped that extensive technical innovation in biomedical devices and materials can be encouraged to advance the field of neuromechanobiology, paving potential ways for the research and rehabilitation of neurotrauma and neurological diseases.
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Affiliation(s)
- Xiaowei Shao
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong, 266237, China.,Suzhou Research Institute, Shandong University, Suzhou, Jiangsu, 215123, China
| | - Zhongqian Liu
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong, 266237, China
| | - Shijie Mao
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong, 266237, China
| | - Lin Han
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong, 266237, China
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Upadhyay K, Alshareef A, Knutsen AK, Johnson CL, Carass A, Bayly PV, Pham DL, Prince JL, Ramesh KT. Development and validation of subject-specific 3D human head models based on a nonlinear visco-hyperelastic constitutive framework. J R Soc Interface 2022; 19:20220561. [PMCID: PMC9554734 DOI: 10.1098/rsif.2022.0561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Computational head models are promising tools for understanding and predicting traumatic brain injuries. Most available head models are developed using inputs (i.e. head geometry, material properties and boundary conditions) from experiments on cadavers or animals and employ hereditary integral-based constitutive models that assume linear viscoelasticity in part of the rate-sensitive material response. This leads to high uncertainty and poor accuracy in capturing the nonlinear brain tissue response. To resolve these issues, a framework for the development of subject-specific three-dimensional head models is proposed, in which all inputs are derived in vivo from the same living human subject: head geometry via magnetic resonance imaging (MRI), brain tissue properties via magnetic resonance elastography (MRE), and full-field strain-response of the brain under rapid head rotation via tagged MRI. A nonlinear, viscous dissipation-based visco-hyperelastic constitutive model is employed to capture brain tissue response. Head models are validated using quantitative metrics that compare spatial strain distribution, temporal strain evolution, and the magnitude of strain maxima, with the corresponding experimental observations from tagged MRI. Results show that our head models accurately capture the strain-response of the brain. Further, employment of the nonlinear visco-hyperelastic constitutive framework provides improvements in the prediction of peak strains and temporal strain evolution over hereditary integral-based models.
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Affiliation(s)
- Kshitiz Upadhyay
- Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218, USA,Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ahmed Alshareef
- Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218, USA,Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Andrew K. Knutsen
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814, USA
| | - Curtis L. Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, USA
| | - Aaron Carass
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Philip V. Bayly
- Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Dzung L. Pham
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814, USA
| | - Jerry L. Prince
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - K. T. Ramesh
- Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218, USA,Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
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40
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McIlvain G, Schneider JM, Matyi MA, McGarry MDJ, Qi Z, Spielberg JM, Johnson CL. Mapping brain mechanical property maturation from childhood to adulthood. Neuroimage 2022; 263:119590. [PMID: 36030061 PMCID: PMC9950297 DOI: 10.1016/j.neuroimage.2022.119590] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/10/2022] [Accepted: 08/23/2022] [Indexed: 02/07/2023] Open
Abstract
Magnetic resonance elastography (MRE) is a phase contrast MRI technique which uses external palpation to create maps of brain mechanical properties noninvasively and in vivo. These mechanical properties are sensitive to tissue microstructure and reflect tissue integrity. MRE has been used extensively to study aging and neurodegeneration, and to assess individual cognitive differences in adults, but little is known about mechanical properties of the pediatric brain. Here we use high-resolution MRE imaging in participants of ages ranging from childhood to adulthood to understand brain mechanical properties across brain maturation. We find that brain mechanical properties differ considerably between childhood and adulthood, and that neuroanatomical subregions have differing maturational trajectories. Overall, we observe lower brain stiffness and greater brain damping ratio with increasing age from 5 to 35 years. Gray and white matter change differently during maturation, with larger changes occurring in gray matter for both stiffness and damping ratio. We also found that subregions of cortical and subcortical gray matter change differently, with the caudate and thalamus changing the most with age in both stiffness and damping ratio, while cortical subregions have different relationships with age, even between neighboring regions. Understanding how brain mechanical properties mature using high-resolution MRE will allow for a deeper understanding of the neural substrates supporting brain function at this age and can inform future studies of atypical maturation.
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Affiliation(s)
- Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Julie M Schneider
- Department of Communication Sciences and Disorders, Louisiana State University, Baton Rouge, LA, United States
| | - Melanie A Matyi
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
| | - Matthew DJ McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States
| | - Zhenghan Qi
- Department of Communication Sciences and Disorders, Northeastern University, Boston, MA, United States
| | - Jeffrey M Spielberg
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States; Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, United States.
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41
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Upadhyay K, Giovanis DG, Alshareef A, Knutsen AK, Johnson CL, Carass A, Bayly PV, Shields MD, Ramesh K. Data-driven Uncertainty Quantification in Computational Human Head Models. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2022; 398:115108. [PMID: 37994358 PMCID: PMC10664838 DOI: 10.1016/j.cma.2022.115108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
Computational models of the human head are promising tools for estimating the impact-induced response of the brain, and thus play an important role in the prediction of traumatic brain injury. The basic constituents of these models (i.e., model geometry, material properties, and boundary conditions) are often associated with significant uncertainty and variability. As a result, uncertainty quantification (UQ), which involves quantification of the effect of this uncertainty and variability on the simulated response, becomes critical to ensure reliability of model predictions. Modern biofidelic head model simulations are associated with very high computational cost and high-dimensional inputs and outputs, which limits the applicability of traditional UQ methods on these systems. In this study, a two-stage, data-driven manifold learning-based framework is proposed for UQ of computational head models. This framework is demonstrated on a 2D subject-specific head model, where the goal is to quantify uncertainty in the simulated strain fields (i.e., output), given variability in the material properties of different brain substructures (i.e., input). In the first stage, a data-driven method based on multi-dimensional Gaussian kernel-density estimation and diffusion maps is used to generate realizations of the input random vector directly from the available data. Computational simulations of a small number of realizations provide input-output pairs for training data-driven surrogate models in the second stage. The surrogate models employ nonlinear dimensionality reduction using Grassmannian diffusion maps, Gaussian process regression to create a low-cost mapping between the input random vector and the reduced solution space, and geometric harmonics models for mapping between the reduced space and the Grassmann manifold. It is demonstrated that the surrogate models provide highly accurate approximations of the computational model while significantly reducing the computational cost. Monte Carlo simulations of the surrogate models are used for uncertainty propagation. UQ of the strain fields highlights significant spatial variation in model uncertainty, and reveals key differences in uncertainty among commonly used strain-based brain injury predictor variables.
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Affiliation(s)
- Kshitiz Upadhyay
- Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Dimitris G. Giovanis
- Department of Civil and Systems Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ahmed Alshareef
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Andrew K. Knutsen
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814, USA
| | - Curtis L. Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, USA
| | - Aaron Carass
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Philip V. Bayly
- Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Michael D. Shields
- Department of Civil and Systems Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - K.T. Ramesh
- Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
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42
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Mechanical Properties of the Extracellular Environment of Human Brain Cells Drive the Effectiveness of Drugs in Fighting Central Nervous System Cancers. Brain Sci 2022; 12:brainsci12070927. [PMID: 35884733 PMCID: PMC9313046 DOI: 10.3390/brainsci12070927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 12/04/2022] Open
Abstract
The evaluation of nanomechanical properties of tissues in health and disease is of increasing interest to scientists. It has been confirmed that these properties, determined in part by the composition of the extracellular matrix, significantly affect tissue physiology and the biological behavior of cells, mainly in terms of their adhesion, mobility, or ability to mutate. Importantly, pathophysiological changes that determine disease development within the tissue usually result in significant changes in tissue mechanics that might potentially affect the drug efficacy, which is important from the perspective of development of new therapeutics, since most of the currently used in vitro experimental models for drug testing do not account for these properties. Here, we provide a summary of the current understanding of how the mechanical properties of brain tissue change in pathological conditions, and how the activity of the therapeutic agents is linked to this mechanical state.
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43
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Meyer T, Marticorena Garcia S, Tzschätzsch H, Herthum H, Shahryari M, Stencel L, Braun J, Kalra P, Kolipaka A, Sack I. Comparison of inversion methods in MR elastography: An open-access pipeline for processing multifrequency shear-wave data and demonstration in a phantom, human kidneys, and brain. Magn Reson Med 2022; 88:1840-1850. [PMID: 35691940 DOI: 10.1002/mrm.29320] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 04/22/2022] [Accepted: 05/11/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE Magnetic resonance elastography (MRE) maps the viscoelastic properties of soft tissues for diagnostic purposes. However, different MRE inversion methods yield different results, which hinder comparison of values, standardization, and establishment of quantitative MRE markers. Here, we introduce an expandable, open-access, webserver-based platform that offers multiple inversion techniques for multifrequency, 3D MRE data. METHODS The platform comprises a data repository and standard MRE inversion methods including local frequency estimation (LFE), direct-inversion based multifrequency dual elasto-visco (MDEV) inversion, and wavenumber-based (k-) MDEV. The use of the platform is demonstrated in phantom data and in vivo multifrequency MRE data of the kidneys and brains of healthy volunteers. RESULTS Detailed maps of stiffness were generated by all inversion methods showing similar detail of anatomy. Specifically, the inner renal cortex had higher shear wave speed (SWS) than renal medulla and outer cortex without lateral differences. k-MDEV yielded higher SWS values than MDEV or LFE (full kidney/brain k-MDEV: 2.71 ± 0.19/1.45 ± 0.14 m/s, MDEV: 2.14 ± 0.16/0.99 ± 0.11 m/s, LFE: 2.12 ± 0.15/0.89 ± 0.06 m/s). CONCLUSION The freely accessible platform supports the comparison of MRE results obtained with different inversion methods, filter thresholds, or excitation frequencies, promoting reproducibility in MRE across community-developed methods.
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Affiliation(s)
- Tom Meyer
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Heiko Tzschätzsch
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Helge Herthum
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Mehrgan Shahryari
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lisa Stencel
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Prateek Kalra
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.,Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Arunark Kolipaka
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.,Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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44
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Coelho A, Sousa N. Magnetic resonance elastography of the ageing brain in normal and demented populations: A systematic review. Hum Brain Mapp 2022; 43:4207-4218. [PMID: 35488708 PMCID: PMC9374877 DOI: 10.1002/hbm.25891] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/12/2022] [Accepted: 04/12/2022] [Indexed: 12/02/2022] Open
Abstract
The aim of this systematic review was to evaluate the ability of magnetic resonance elastography (MRE) to identify significant changes in brain mechanical properties during normal and pathological aging. PubMed, Web of Science and Scopus were searched for human studies using MRE to assess brain mechanical properties in cognitively healthy individuals, individuals at risk of dementia or patients diagnosed with dementia. Study characteristics, sample demographics, clinical characterization and main MRE outcomes were summarized in a table. A total of 19 studies (nine aging, 10 dementia), comprising 700 participants, were included. The main findings were decreased cerebral stiffness along aging, with rates of annual change ranging from −0.008 to −0.025 kPa per year. Also, there were regional differences in the age effect on brain stiffness. Concerning demented patients, differential patterns of stiffness were found for distinct dementia subtypes. Alzheimer's disease and frontotemporal dementia exhibited decreased brain stiffness in comparison to cognitively healthy controls and significant declines were found in regions known to be affected by the disease. In normal pressure hydrocephalus, the results were not consistent across studies, and in dementia with Lewy bodies no significant differences in brain stiffness were found. In conclusion, aging is characterized by the softening of brain tissue and this event is even more pronounced in pathological aging, such as dementia. MRE technique could be applied as a sensible diagnostic tool to identify deviations from normal aging and develop new brain biomarkers of cognitive decline/dementia that would help promote healthier cognitive aging.
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Affiliation(s)
- Ana Coelho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Clinical Academic Center-Braga, Braga, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Clinical Academic Center-Braga, Braga, Portugal.,Association P5 Digital Medical Center (ACMP5), Braga, Portugal
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45
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Hiscox LV, McGarry MDJ, Johnson CL. Evaluation of cerebral cortex viscoelastic property estimation with nonlinear inversion magnetic resonance elastography. Phys Med Biol 2022; 67. [PMID: 35316794 PMCID: PMC9208651 DOI: 10.1088/1361-6560/ac5fde] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/22/2022] [Indexed: 12/25/2022]
Abstract
Objective. Magnetic resonance elastography (MRE) of the brain has shown promise as a sensitive neuroimaging biomarker for neurodegenerative disorders; however, the accuracy of performing MRE of the cerebral cortex warrants investigation due to the unique challenges of studying thinner and more complex geometries.Approach. A series of realistic, whole-brain simulation experiments are performed to examine the accuracy of MRE to measure the viscoelasticity (shear stiffness,μ, and damping ratio, ξ) of cortical structures predominantly effected in aging and neurodegeneration. Variations to MRE spatial resolution and the regularization of a nonlinear inversion (NLI) approach are examined.Main results. Higher-resolution MRE displacement data (1.25 mm isotropic resolution) and NLI with a low soft prior regularization weighting provided minimal measurement error compared to other studied protocols. With the optimized protocol, an average error inμand ξ was 3% and 11%, respectively, when compared with the known ground truth. Mid-line structures, as opposed to those on the cortical surface, generally display greater error. Varying model boundary conditions and reducing the thickness of the cortex by up to 0.67 mm (which is a realistic portrayal of neurodegenerative pathology) results in no loss in reconstruction accuracy.Significance. These experiments establish quantitative guidelines for the accuracy expected ofin vivoMRE of the cortex, with the proposed method providing valid MRE measures for future investigations into cortical viscoelasticity and relationships with health, cognition, and behavior.
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Affiliation(s)
- Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States of America.,Department of Psychology, University of Bath, Bath, United Kingdom
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States of America
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46
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Hu L, Yang S, Jin B, Wang C. Advanced Neuroimaging Role in Traumatic Brain Injury: A Narrative Review. Front Neurosci 2022; 16:872609. [PMID: 35495065 PMCID: PMC9043279 DOI: 10.3389/fnins.2022.872609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/14/2022] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) is a common source of morbidity and mortality among civilians and military personnel. Initial routine neuroimaging plays an essential role in rapidly assessing intracranial injury that may require intervention. However, in the context of TBI, limitations of routine neuroimaging include poor visualization of more subtle changes of brain parenchymal after injury, poor prognostic ability and inability to analyze cerebral perfusion, metabolite and mechanical properties. With the development of modern neuroimaging techniques, advanced neuroimaging techniques have greatly boosted the studies in the diagnosis, prognostication, and eventually impacting treatment of TBI. Advances in neuroimaging techniques have shown potential, including (1) Ultrasound (US) based techniques (contrast-enhanced US, intravascular US, and US elastography), (2) Magnetic resonance imaging (MRI) based techniques (diffusion tensor imaging, magnetic resonance spectroscopy, perfusion weighted imaging, magnetic resonance elastography and functional MRI), and (3) molecular imaging based techniques (positron emission tomography and single photon emission computed tomography). Therefore, in this review, we aim to summarize the role of these advanced neuroimaging techniques in the evaluation and management of TBI. This review is the first to combine the role of the US, MRI and molecular imaging based techniques in TBI. Advanced neuroimaging techniques have great potential; still, there is much to improve. With more clinical validation and larger studies, these techniques will be likely applied for routine clinical use from the initial research.
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Affiliation(s)
- Ling Hu
- Department of Ultrasound, Hangzhou Women’s Hospital, Hangzhou, China
| | - Siyu Yang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bo Jin
- Department of Neurology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Chao Wang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- *Correspondence: Chao Wang,
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47
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Jyoti D, McGarry M, Van Houten E, Sowinski D, Bayly PV, Johnson CL, Paulsen K. Quantifying stability of parameter estimates for in vivonearly incompressible transversely-isotropic brain MR elastography. Biomed Phys Eng Express 2022; 8. [PMID: 35299161 PMCID: PMC9272913 DOI: 10.1088/2057-1976/ac5ebe] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/17/2022] [Indexed: 11/12/2022]
Abstract
Easily computable quality metrics for measured medical data at point-of-care are important for imaging technologies involving offline reconstruction. Accordingly, we developed a new data quality metric forin vivotransversely-isotropic (TI) magnetic resonance elastography (MRE) based on a generalization of the widely accepted octahedral shear-strain calculation. The metric uses MRE displacement data and an estimate of the TI property field to yield a 'stability map' which predicts regions of low versus high accuracy in the resulting material property reconstructions. We can also calculate an average TI parameter stability (TIPS) score over all voxels in a region of interest for a given measurement to indicate how reliable the recovered mechanical property estimate for the region is expected to be. The calculation is rapid and places little demand on computing resources compared to the computationally intensive material property reconstruction from non-linear inversion (TI-NLI) of displacement fields, making it ideal for point-of-care evaluation of data quality. We test the predictions of the stability map for both simulated phantoms andin vivohuman brain data. We used a range of different displacement datasets from vibrations applied in the anterior-posterior (AP), left-right (LR) and combined AP + LR directions. The TIPS and variability maps (noise sensitivity or variation from the mean of repeated MRE scans) were consistently anti-correlated. Notably, Spearman correlation coefficients ∣R∣>0.6 were found between variability and TIPS score for individual white matter tracts within vivodata. These observations demonstrate the reliability and promise of this data quality metric to screen data rapidly in realistic clinical MRE applications.
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Affiliation(s)
- Dhrubo Jyoti
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
| | - Matthew McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
| | | | - Damian Sowinski
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
| | - Philip V Bayly
- Washington University in St Louis, St Louis, MO, 63130, United States of America
| | - Curtis L Johnson
- University of Delaware, Newark, DE 19716, United States of America
| | - Keith Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America.,Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, United States of America
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48
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Aunan-Diop JS, Pedersen CB, Halle B, Jensen U, Munthe S, Harbo F, Johannsson B, Poulsen FR. Magnetic resonance elastography in normal pressure hydrocephalus-a scoping review. Neurosurg Rev 2022; 45:1157-1169. [PMID: 34687356 DOI: 10.1007/s10143-021-01669-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/05/2021] [Accepted: 10/04/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Magnetic resonance elastography (MRE) of the brain allows quantitative measurement of tissue mechanics. Multiple studies are exploring possible applications in normal pressure hydrocephalus (NPH) in clinical and paraclinical contexts. This is of great interest in neurological surgery due to challenges related to diagnosis and prediction of treatment effects. In this scoping review, we present a topical overview and discuss the current literature, with particular attention to clinical implications and current challenges. METHODS The protocol was based on the PRISMA extension for scoping reviews. After a systematic database search (PubMed, Embase, and Web of Science), the articles were screened for relevance. Thirty articles were subject to detailed screening, and key technical and clinical data items were extracted. The inclusion criteria included the use of MRE on human subjects with NPH. RESULTS Seven articles were included in the final study. These studies had various objectives including the role of MRE in the assessment of regional elastic changes in NPH, shunt effect, and evaluation of NPH symptoms. MRE revealed patterns of mechanical changes in NPH that differed from other dementias. Regional MRE changes were associated with specific NPH signs and symptoms. Neurosurgical shunting caused partial normalization in tissue scaffold parameters. The studies were highly heterogeneous in technical aspects and design. CONCLUSION MRE studies in NPH are still limited by few participants, variable cohorts, inconsistent methodologies, and technical challenges, but the approach shows great potential for future clinical application.
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Affiliation(s)
- Jan Saip Aunan-Diop
- Department of Neurosurgery, Odense University Hospital, Kløvervænget 47, Entrance 44, 5000, Odense C, Denmark. .,University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
| | - Christian Bonde Pedersen
- Department of Neurosurgery, Odense University Hospital, Kløvervænget 47, Entrance 44, 5000, Odense C, Denmark
| | - Bo Halle
- Department of Neurosurgery, Odense University Hospital, Kløvervænget 47, Entrance 44, 5000, Odense C, Denmark
| | - Ulla Jensen
- Department of Radiology, Odense University Hospital, Kløvervænget 47, Entrance 27, 5000, Odense C, Denmark
| | - Sune Munthe
- Department of Neurosurgery, Odense University Hospital, Kløvervænget 47, Entrance 44, 5000, Odense C, Denmark
| | - Fredrik Harbo
- Department of Radiology, Odense University Hospital, Kløvervænget 47, Entrance 27, 5000, Odense C, Denmark
| | - Bjarni Johannsson
- Department of Neurosurgery, Odense University Hospital, Kløvervænget 47, Entrance 44, 5000, Odense C, Denmark
| | - Frantz Rom Poulsen
- Department of Neurosurgery, Odense University Hospital, Kløvervænget 47, Entrance 44, 5000, Odense C, Denmark.,University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
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49
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Hannum AJ, McIlvain G, Sowinski D, McGarry MD, Johnson CL. Correlated noise in brain magnetic resonance elastography. Magn Reson Med 2022; 87:1313-1328. [PMID: 34687069 PMCID: PMC8776601 DOI: 10.1002/mrm.29050] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/13/2021] [Accepted: 09/28/2021] [Indexed: 12/22/2022]
Abstract
PURPOSE Magnetic resonance elastography (MRE) uses phase-contrast MRI to generate mechanical property maps of the in vivo brain through imaging of tissue deformation from induced mechanical vibration. The mechanical property estimation process in MRE can be susceptible to noise from physiological and mechanical sources encoded in the phase, which is expected to be highly correlated. This correlated noise has yet to be characterized in brain MRE, and its effects on mechanical property estimates computed using inversion algorithms are undetermined. METHODS To characterize the effects of signal noise in MRE, we conducted 3 experiments quantifying (1) physiomechanical sources of signal noise, (2) physiological noise because of cardiac-induced movement, and (3) impact of correlated noise on mechanical property estimates. We use a correlation length metric to estimate the extent that correlated signal persists in MRE images and demonstrate the effect of correlated noise on property estimates through simulations. RESULTS We found that both physiological noise and vibration noise were greater than image noise and were spatially correlated across all subjects. Added physiological and vibration noise to simulated data resulted in property maps with higher error than equivalent levels of Gaussian noise. CONCLUSION Our work provides the foundation to understand contributors to brain MRE data quality and provides recommendations for future work to correct for signal noise in MRE.
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Affiliation(s)
- Ariel J. Hannum
- Department of Biomedical Engineering, University of Delaware, Newark, DE
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE
| | - Damian Sowinski
- Thayer School of Engineering, Dartmouth College, Hanover, NH
| | | | - Curtis L. Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE
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50
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Harkos C, Svensson SF, Emblem KE, Stylianopoulos T. Inducing Biomechanical Heterogeneity in Brain Tumor Modeling by MR Elastography: Effects on Tumor Growth, Vascular Density and Delivery of Therapeutics. Cancers (Basel) 2022; 14:cancers14040884. [PMID: 35205632 PMCID: PMC8870149 DOI: 10.3390/cancers14040884] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary Biomechanical forces aggravate brain tumor progression. In this study, magnetic resonance elastography (MRE) is employed to extract tissue biomechanical properties from five glioblastoma patients and a healthy subject, and data are incorporated in a mathematical model that simulates tumor growth. Mathematical modeling enables further understanding of glioblastoma development and allows patient-specific predictions for tumor vascularity and delivery of drugs. Incorporating MRE data results in a more realistic intratumoral distribution of mechanical stress and anisotropic tumor growth and a better description of subsequent events that are closely related to the development of stresses, including heterogeneity of the tumor vasculature and intrapatient variations in tumor perfusion and delivery of drugs. Abstract The purpose of this study is to develop a methodology that incorporates a more accurate assessment of tissue mechanical properties compared to current mathematical modeling by use of biomechanical data from magnetic resonance elastography. The elastography data were derived from five glioblastoma patients and a healthy subject and used in a model that simulates tumor growth, vascular changes due to mechanical stresses and delivery of therapeutic agents. The model investigates the effect of tumor-specific biomechanical properties on tumor anisotropic growth, vascular density heterogeneity and chemotherapy delivery. The results showed that including elastography data provides a more realistic distribution of the mechanical stresses in the tumor and induces anisotropic tumor growth. Solid stress distribution differs among patients, which, in turn, induces a distinct functional vascular density distribution—owing to the compression of tumor vessels—and intratumoral drug distribution for each patient. In conclusion, incorporating elastography data results in a more accurate calculation of intratumoral mechanical stresses and enables a better mathematical description of subsequent events, such as the heterogeneous development of the tumor vasculature and intrapatient variations in tumor perfusion and delivery of drugs.
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Affiliation(s)
- Constantinos Harkos
- Cancer Biophysics Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia 1678, Cyprus;
| | - Siri Fløgstad Svensson
- Division of Radiology and Nuclear Medicine, Department of Diagnostic Physics, Oslo University Hospital, 0372 Oslo, Norway; (S.F.S.); (K.E.E.)
- Department of Physics, The Faculty of Mathematics and Natural Sciences, University of Oslo, 0371 Oslo, Norway
| | - Kyrre E. Emblem
- Division of Radiology and Nuclear Medicine, Department of Diagnostic Physics, Oslo University Hospital, 0372 Oslo, Norway; (S.F.S.); (K.E.E.)
| | - Triantafyllos Stylianopoulos
- Cancer Biophysics Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia 1678, Cyprus;
- Correspondence:
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