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Hojo E, Sui Y, Shan X, Zheng K, Rossman P, Manduca A, Powell GM, An KN, Zhao KD, Bauer BA, Ehman RL, Yin Z. MR elastography-based slip interface imaging (SII) for functional assessment of myofascial interfaces: A feasibility study. Magn Reson Med 2024; 92:676-687. [PMID: 38523575 PMCID: PMC11142878 DOI: 10.1002/mrm.30087] [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: 12/10/2023] [Revised: 02/28/2024] [Accepted: 02/28/2024] [Indexed: 03/26/2024]
Abstract
PURPOSE Abnormal adherence at functional myofascial interfaces is hypothesized as an important phenomenon in myofascial pain syndrome. This study aimed to investigate the feasibility of MR elastography (MRE)-based slip interface imaging (SII) to visualize and assess myofascial mobility in healthy volunteers. METHODS SII was used to assess local shear strain at functional myofascial interfaces in the flexor digitorum profundus (FDP) and thighs. In the FDP, MRE was performed at 90 Hz vibration to each index, middle, ring, and little finger. Two thigh MRE scans were performed at 40 Hz with knees flexed and extended. The normalized octahedral shear strain (NOSS) maps were calculated to visualize myofascial slip interfaces. The entropy of the probability distribution of the gradient NOSS was computed for the two knee positions at the intermuscular interface between vastus lateralis and vastus intermedius, around rectus femoris, and between vastus intermedius and vastus medialis. RESULTS NOSS map depicted distinct functional slip interfaces in the FDP for each finger. Compared to knee flexion, clearer slip interfaces and larger gradient NOSS entropy at the vastus lateralis-vastus intermedius interface were observed during knee extension, where the quadriceps are not passively stretched. This suggests the optimal position for using SII to visualize myofascial slip interface in skeletal muscles is when muscles are not subjected to any additional force. CONCLUSION The study demonstrated that MRE-based SII can visualize and assess myofascial interface mobility in extremities. The results provide a foundation for investigating the hypothesis that myofascial pain syndrome is characterized by changes in the mobility of myofascial interfaces.
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Affiliation(s)
- Emi Hojo
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Yi Sui
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Xiang Shan
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Keni Zheng
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Phillip Rossman
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Armando Manduca
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Garret M. Powell
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Kai-Nan An
- Orthopedics Research, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Kristin D. Zhao
- Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Brent A. Bauer
- General Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Richard L. Ehman
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Ziying Yin
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
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Noureddin N, Copur-Dahi N, Loomba R. Monitoring disease progression in metabolic dysfunction-associated steatotic liver disease. Aliment Pharmacol Ther 2024; 59 Suppl 1:S41-S51. [PMID: 38813822 PMCID: PMC11141723 DOI: 10.1111/apt.17752] [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: 09/01/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 05/31/2024]
Abstract
BACKGROUND Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common cause of chronic liver disease. Its prevalence is increasing with the epidemic of obesity and metabolic syndrome. MASLD progression into metabolic dysfunction-associated steatohepatitis (MASH) and advanced fibrosis may lead to decompensated cirrhosis and development of liver-related events, hepatocellular carcinoma and death. Monitoring disease progression is critical in decreasing morbidity, mortality, need for transplant and economic burden. Assessing for treatment response once FDA-approved medications are available is still an unmet clinical need. AIMS To explore the most up-to-date literature on testing used for monitoring disease progression and treatment response METHODS: We searched PubMed from inception to 15 August 2023, using the following MeSH terms: 'MASLD', 'Metabolic dysfunction-associated steatotic liver disease', 'MASH', 'metabolic dysfunction-associated steatohepatitis', 'Non-Alcoholic Fatty Liver Disease', 'NAFLD', 'non-alcoholic steatohepatitis', 'NASH', 'Biomarkers', 'clinical trial'. Articles were also identified through searches of the authors' files. The final reference list was generated based on originality and relevance to this review's broad scope, considering only papers published in English. RESULTS We have cited 101 references in this review detailing methods to monitor MASLD disease progression and treatment response. CONCLUSION Various biomarkers can be used in different care settings to monitor disease progression. Further research is needed to validate noninvasive tests more effectively.
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Affiliation(s)
- Nabil Noureddin
- MASLD Research Center, University of California at San Diego, La Jolla, CA, USA
- Division of Gastroenterology & Hepatology, University of California at San Diego, La Jolla, CA, USA
| | - Nedret Copur-Dahi
- Division of Gastroenterology & Hepatology, University of California at San Diego, La Jolla, CA, USA
| | - Rohit Loomba
- MASLD Research Center, University of California at San Diego, La Jolla, CA, USA
- Division of Gastroenterology & Hepatology, University of California at San Diego, La Jolla, CA, USA
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Williams LT, Cao Z, Lateef AH, McGarry MDJ, Corbin EA, Johnson CL. Viscoelastic polyacrylamide MR elastography phantoms with tunable damping ratio independent of shear stiffness. J Mech Behav Biomed Mater 2024; 154:106522. [PMID: 38537609 PMCID: PMC11023745 DOI: 10.1016/j.jmbbm.2024.106522] [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: 01/16/2024] [Revised: 03/07/2024] [Accepted: 03/21/2024] [Indexed: 04/16/2024]
Abstract
Physiologically modeled test samples with known properties and characteristics, or phantoms, are essential for developing sensitive, repeatable, and accurate quantitative MRI techniques. Magnetic resonance elastography (MRE) is one such technique used to estimate tissue mechanical properties, and it is advantageous to use phantoms with independently tunable mechanical properties to benchmark the accuracy of MRE methods. Phantoms with tunable shear stiffness are commonly used for MRE, but tuning the viscosity or damping ratio has proven to be difficult. A promising candidate for MRE phantoms with tunable damping ratio is polyacrylamide (PAA). While pure PAA has very low attenuation, viscoelastic hydrogels have been made by entrapping linear polyacrylamide strands (LPAA) within the PAA network. In this study, we evaluate the use of LPAA/PAA gels as physiologically accurate phantoms with tunable damping ratio, independent of shear stiffness, via MRE. Phantoms were made with 15.3 wt% PAA while the LPAA concentration ranged from 4.5 wt% to 8.0 wt%. MRE was performed at 9.4 T with 400 Hz vibration on all phantoms revealing a strong, positive correlation between damping ratio and LPAA content (p < 0.001). There was no significant correlation between shear stiffness and LPAA content, confirming a constant PAA concentration yielded constant shear stiffness. Rheometry at 10 Hz was performed to verify the damping ratio of the phantoms. Nearly identical slopes for damping ratio versus LPAA content were found from both MRE and rheometry (0.0073 and 0.0075 respectively). Ultimately, this study validates the adaptation of polyacrylamide gels into physiologically-relevant MRE phantoms to enable testing of MRE estimates of damping ratio.
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Affiliation(s)
- L Tyler Williams
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Zheng Cao
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Ali H Lateef
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | | | - Elise A Corbin
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA.
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Hoffmann E, Masthoff M, Kunz WG, Seidensticker M, Bobe S, Gerwing M, Berdel WE, Schliemann C, Faber C, Wildgruber M. Multiparametric MRI for characterization of the tumour microenvironment. Nat Rev Clin Oncol 2024; 21:428-448. [PMID: 38641651 DOI: 10.1038/s41571-024-00891-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2024] [Indexed: 04/21/2024]
Abstract
Our understanding of tumour biology has evolved over the past decades and cancer is now viewed as a complex ecosystem with interactions between various cellular and non-cellular components within the tumour microenvironment (TME) at multiple scales. However, morphological imaging remains the mainstay of tumour staging and assessment of response to therapy, and the characterization of the TME with non-invasive imaging has not yet entered routine clinical practice. By combining multiple MRI sequences, each providing different but complementary information about the TME, multiparametric MRI (mpMRI) enables non-invasive assessment of molecular and cellular features within the TME, including their spatial and temporal heterogeneity. With an increasing number of advanced MRI techniques bridging the gap between preclinical and clinical applications, mpMRI could ultimately guide the selection of treatment approaches, precisely tailored to each individual patient, tumour and therapeutic modality. In this Review, we describe the evolving role of mpMRI in the non-invasive characterization of the TME, outline its applications for cancer detection, staging and assessment of response to therapy, and discuss considerations and challenges for its use in future medical applications, including personalized integrated diagnostics.
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Affiliation(s)
- Emily Hoffmann
- Clinic of Radiology, University of Münster, Münster, Germany
| | - Max Masthoff
- Clinic of Radiology, University of Münster, Münster, Germany
| | - Wolfgang G Kunz
- Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | - Max Seidensticker
- Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | - Stefanie Bobe
- Gerhard Domagk Institute of Pathology, University Hospital Münster, Münster, Germany
| | - Mirjam Gerwing
- Clinic of Radiology, University of Münster, Münster, Germany
| | | | | | - Cornelius Faber
- Clinic of Radiology, University of Münster, Münster, Germany
| | - Moritz Wildgruber
- Department of Radiology, University Hospital, LMU Munich, Munich, Germany.
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Ehman RL. Research Reveals a Potential Role for MR Elastography in Preoperative Evaluation of Endometrial Cancer. Radiology 2024; 311:e241034. [PMID: 38832879 DOI: 10.1148/radiol.241034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Affiliation(s)
- Richard L Ehman
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
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Ishihara Y, Numano T, Ito D, Nishijo H, Takamoto K, Kikuchi J, Konuma S, Oka H. Development of a suitable vibration pad for renal MR elastography. Magn Reson Imaging 2024; 109:120-126. [PMID: 38492785 DOI: 10.1016/j.mri.2024.03.013] [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: 01/26/2024] [Revised: 03/04/2024] [Accepted: 03/13/2024] [Indexed: 03/18/2024]
Abstract
The aim of this study was to develop a vibration pad suitable for renal MR elastography (MRE). Chronic kidney disease (CKD) is a progressive condition affecting >800 million people worldwide. Renal fibrosis is a common pathological feature of CKD that causes fibrotic regions to be much stiffer than those in normal renal tissues. Therefore, MRE can be used to diagnose CKD because it can image organ stiffness. In MRE, the shear modulus is obtained from the wavelength of the shear waves. Therefore, it is highly important to propagate shear waves with sufficient vibration strength in the tissue. By using a three-dimensional (3D) printer, we created a "Flexible Pad" suitable for renal MRE. The Flexible Pad was placed under the back of the participant in the supine position and deformed in response to the participant's weight, adhering closely to the body surface. Six healthy volunteers participated in this study. Our Flexible Pad allowed for coherent shear waves (clear waves with little scattering and interference) to be efficiently transmitted to the kidney deep-lying tissues in the abdomen. The shear moduli of the kidney (n = 6) were 8.95 ± 0.84 kPa in the right kidney and 9.70 ± 0.99 kPa in the left kidney. Our results indicate that using our Flexible Pad for renal MRE can provide a more reliable measurement of renal shear modulus.
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Affiliation(s)
- Yoshito Ishihara
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Tomokazu Numano
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan.
| | - Daiki Ito
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Office of Radiation Technology, Keio University Hospital, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Hisao Nishijo
- Department of Sport and Health Sciences, Faculty of Human Sciences, University of East Asia, 2-1, Ichinomiya Gakuen-cho, Shimonoseki-shi, Yamaguchi 751-8503, Japan
| | - Koichi Takamoto
- Department of Sport and Health Sciences, Faculty of Human Sciences, University of East Asia, 2-1, Ichinomiya Gakuen-cho, Shimonoseki-shi, Yamaguchi 751-8503, Japan
| | - Jo Kikuchi
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Shota Konuma
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Hiromu Oka
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
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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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8
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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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Masud AA, Liu J. Ultrasonic surface acoustic wave elastography: A review of basic theories, technical developments, and medical applications. Med Phys 2024; 51:3220-3244. [PMID: 38597908 DOI: 10.1002/mp.17063] [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: 08/23/2023] [Revised: 02/19/2024] [Accepted: 03/18/2024] [Indexed: 04/11/2024] Open
Abstract
Physiological and pathological changes in tissues often cause changes in tissue mechanical properties, making tissue elastography an effective modality in medical imaging. Among the existing elastography methods, ultrasound elastography is of great interest due to the inherent advantages of ultrasound imaging technology, such as low cost, portability, safety, and wide availability. However, most current ultrasound elastography methods are based on the bulk shear wave; they can image deep tissues but cannot image superficial tissues. To address this challenge, ultrasonic elastography methods based on surface acoustic waves have been proposed. In this paper, we present a comprehensive review of ultrasound-based surface acoustic wave elastography techniques, including their theoretical foundations, technical implementations, and existing medical applications. The goal is to provide a concise summary of the state-of-the-art of this field, hoping to offer a reliable reference for the further development of these techniques and foster the expansion of their medical applications.
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Affiliation(s)
- Abdullah Al Masud
- Biomedical Acoustics Research Laboratory, Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA
| | - Jingfei Liu
- Biomedical Acoustics Research Laboratory, Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA
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Ito D, Numano T, Habe T, Okuda S, Nozaki T, Jinzaki M. Fast abdominal magnetic resonance elastography with simultaneous encoding of three-dimensional displacements. Magn Reson Imaging 2024; 108:138-145. [PMID: 38360120 DOI: 10.1016/j.mri.2024.02.009] [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: 10/21/2023] [Revised: 02/07/2024] [Accepted: 02/11/2024] [Indexed: 02/17/2024]
Abstract
Three-dimensional (3D) magnetic resonance elastography (MRE) is more accurate than two-dimensional (2D) MRE; however, it requires long-term acquisition. This study aimed to reduce the acquisition time of abdominal 3D MRE using a new sample interval modulation (short-SLIM) approach that can acquire all three motions faster while reducing the prolongation of echo time and flow compensation. To this end, two types of phantom studies and an in vivo test of the liver in three healthy volunteers were performed to compare the performances of conventional spin-echo echo-planar (SE-EPI) MRE, conventional SLIM and short-SLIM. One phantom study measured the mean amplitude and shear modulus within the overall region of a homogeneous phantom by changing the mechanical vibration power to assess the robustness to the lowered phase-to-noise ratio in short-SLIM. The other measured the mean shear modulus in the stiff and background materials of a phantom with an embedded stiffer rod to assess the performance of short-SLIM for complex wave patterns with wave interference. The Spearman's rank correlation coefficient was used to assess similarity of elastograms in the rod-embedded phantom and liver between methods. The results of the phantom study changing the vibration power indicated that there was little difference between conventional MRE and short-SLIM. Moreover, the elastogram pattern and the mean shear modulus in the rod-embedded phantom in conventional SLIM and short-SLIM did not change for conventional MRE; the liver test also showed a small difference between the acquisition techniques. This study demonstrates that short-SLIM can provide MRE results comparable to those of conventional MRE. Short-SLIM can reduce the total acquisition time by a factor of 2.25 compared to conventional 3D MRE time, leading to an improvement in the accuracy of shear modulus estimation by suppressing the patient movements.
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Affiliation(s)
- Daiki Ito
- Office of Radiation Technology, Keio University Hospital, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan; Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan.
| | - Tomokazu Numano
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan
| | - Tetsushi Habe
- Office of Radiation Technology, Keio University Hospital, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Shigeo Okuda
- Department of Diagnostic Radiology, National Tokyo Medical Center, 2-5-1, Higashigaoka, Meguro-ku, Tokyo 152-8902, Japan; Department of Radiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Taiki Nozaki
- Department of Radiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masahiro Jinzaki
- Department of Radiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Kim GS, Moon HH, Lee HS, Jeong JS. Compound Acoustic Radiation Force Impulse Imaging of Bovine Eye by Using Phase-Inverted Ultrasound Transducer. SENSORS (BASEL, SWITZERLAND) 2024; 24:2700. [PMID: 38732804 PMCID: PMC11085659 DOI: 10.3390/s24092700] [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: 01/15/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024]
Abstract
In general, it is difficult to visualize internal ocular structure and detect a lesion such as a cataract or glaucoma using the current ultrasound brightness-mode (B-mode) imaging. This is because the internal structure of the eye is rich in moisture, resulting in a lack of contrast between tissues in the B-mode image, and the penetration depth is low due to the attenuation of the ultrasound wave. In this study, the entire internal ocular structure of a bovine eye was visualized in an ex vivo environment using the compound acoustic radiation force impulse (CARFI) imaging scheme based on the phase-inverted ultrasound transducer (PIUT). In the proposed method, the aperture of the PIUT is divided into four sections, and the PIUT is driven by the out-of-phase input signal capable of generating split-focusing at the same time. Subsequently, the compound imaging technique was employed to increase signal-to-noise ratio (SNR) and to reduce displacement error. The experimental results demonstrated that the proposed technique could provide an acoustic radiation force impulse (ARFI) image of the bovine eye with a broader depth-of-field (DOF) and about 80% increased SNR compared to the conventional ARFI image obtained using the in-phase input signal. Therefore, the proposed technique can be one of the useful techniques capable of providing the image of the entire ocular structure to diagnose various eye diseases.
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Affiliation(s)
| | | | | | - Jong Seob Jeong
- Department of Biomedical Engineering, Dongguk University, Seoul 04620, Republic of Korea; (G.S.K.); (H.H.M.); (H.S.L.)
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Plut D. Editorial Comment: Radiology-Improving Sight and Touch. AJR Am J Roentgenol 2024. [PMID: 38656119 DOI: 10.2214/ajr.24.31327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Affiliation(s)
- Domen Plut
- Clinical Radiology Institute, University Medical Centre Ljubljana, Zaloška cesta 7, 1000 Ljubljana, Slovenia
- University of Ljubljana Faculty of Medicine, Korytkova 2, 1000 Ljubljana, Slovenia
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13
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Kiss C, Wurth S, Heschl B, Khalil M, Gattringer T, Enzinger C, Ropele S. Low-frequency MR elastography reveals altered deep gray matter viscoelasticity in multiple sclerosis. Neuroimage Clin 2024; 42:103606. [PMID: 38669859 PMCID: PMC11068637 DOI: 10.1016/j.nicl.2024.103606] [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: 11/25/2023] [Revised: 02/23/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024]
Abstract
INTRODUCTION Brain viscoelasticity as assessed by magnetic resonance elastography (MRE) has been discussed as a promising surrogate of microstructural alterations due to neurodegenerative processes. Existing studies indicate that multiple sclerosis (MS) is associated with a global reduction in brain stiffness. However, no study to date systematically investigated the MS-related characteristics of brain viscoelasticity separately in normal-appearing white matter (NAWM), deep gray matter (DGM) and T2-hyperintense white matter (WM) lesions. METHODS 70 MS patients and 42 healthy volunteers underwent whole-cerebral MRE using a stimulated echo sequence (DENSE) with a low-frequency mechanical excitation at 20 Hertz. The magnitude |G∗| (Pa) and phase angle φ (rad) of the complex shear modulus G∗ were reconstructed by multifrequency dual elasto-visco (MDEV) inversion and related to structural imaging and clinical parameters. RESULTS We observed φ in the thalamus to be higher by 4.3 % in patients relative to healthy controls (1.11 ± 0.07 vs. 1.06 ± 0.07, p < 0.0001). Higher Expanded Disability Status Scale (EDSS) scores were negatively associated with φ in the basal ganglia (p = 0.01). We measured φ to be lower in MS lesions compared to surrounding NAWM (p = 0.001), which was most prominent for lesions in the temporal lobe (1.01 ± 0.22 vs. 1.06 ± 0.19, p = 0.003). Age was associated with lower values of |G∗| (p = 0.04) and φ (p = 0.004) in the thalamus of patients. No alteration in NAWM stiffness relative to WM in healthy controls was observed. CONCLUSION Low-frequency elastography in MS patients reveals age-independent alterations in the viscoelasticity of deep gray matter at early stages of disease.
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Affiliation(s)
- Christian Kiss
- Department of Neurology, Medical University of Graz, Austria.
| | - Sebastian Wurth
- Department of Neurology, Medical University of Graz, Austria.
| | - Bettina Heschl
- Department of Neurology, Medical University of Graz, Austria.
| | - Michael Khalil
- Department of Neurology, Medical University of Graz, Austria.
| | | | | | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Austria; Neuroimaging Research Unit, Department of Neurology, Medical University of Graz, Austria.
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14
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Marmin A, Dufour N, Facca S, Catheline S, Chatelin S, Nahas A. Full-field noise-correlation elastography for in-plane mechanical anisotropy imaging. BIOMEDICAL OPTICS EXPRESS 2024; 15:2622-2635. [PMID: 38633096 PMCID: PMC11019699 DOI: 10.1364/boe.516166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 04/19/2024]
Abstract
Elastography contrast imaging has great potential for the detection and characterization of abnormalities in soft biological tissues to help physicians in diagnosis. Transient shear-waves elastography has notably shown promising results for a range of clinical applications. In biological soft tissues such as muscle, high mechanical anisotropy implies different stiffness estimations depending on the direction of the measurement. In this study, we propose the evolution of a noise-correlation elastography approach for in-plane anisotropy mapping. This method is shown to retrieve anisotropy from simulation images before being validated on agarose anisotropic tissue-mimicking phantoms, and the first results on in-vivo biological fibrous tissues are presented.
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Affiliation(s)
- Agathe Marmin
- Université de
Strasbourg, CNRS, ICube, UMR 7357, 67000 Strasbourg,
France
| | - Nina Dufour
- Université de
Strasbourg, CNRS, ICube, UMR 7357, 67000 Strasbourg,
France
| | - Sybille Facca
- Université de
Strasbourg, CNRS, ICube, UMR 7357, 67000 Strasbourg,
France
- Department of Hand Surgery, SOS hand,
University Hospital of Strasbourg, FMTS, 1
avenue Molière, 67000 Strasbourg, France
| | - Stefan Catheline
- LabTAU, Inserm, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003 Lyon, France
| | - Simon Chatelin
- Université de
Strasbourg, CNRS, ICube, UMR 7357, 67000 Strasbourg,
France
- RoDIn, Inserm ERL1328, 1 place de l’Hôpital, 67000 Strasbourg, France
| | - Amir Nahas
- Université de
Strasbourg, CNRS, ICube, UMR 7357, 67000 Strasbourg,
France
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15
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Yin Z, Li GY, Zhang Z, Zheng Y, Cao Y. SWENet: A Physics-Informed Deep Neural Network (PINN) for Shear Wave Elastography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2024; 43:1434-1448. [PMID: 38032772 DOI: 10.1109/tmi.2023.3338178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Shear wave elastography (SWE) enables the measurement of elastic properties of soft materials in a non-invasive manner and finds broad applications in various disciplines. The state-of-the-art SWE methods rely on the measurement of local shear wave speeds to infer material parameters and suffer from wave diffraction when applied to soft materials with strong heterogeneity. In the present study, we overcome this challenge by proposing a physics-informed neural network (PINN)-based SWE (SWENet) method. The spatial variation of elastic properties of inhomogeneous materials has been introduced in the governing equations, which are encoded in SWENet as loss functions. Snapshots of wave motions have been used to train neural networks, and during this course, the elastic properties within a region of interest illuminated by shear waves are inferred simultaneously. We performed finite element simulations, tissue-mimicking phantom experiments, and ex vivo experiments to validate the method. Our results show that the shear moduli of soft composites consisting of matrix and inclusions of several millimeters in cross-section dimensions with either regular or irregular geometries can be identified with excellent accuracy. The advantages of the SWENet over conventional SWE methods consist of using more features of the wave motions and enabling seamless integration of multi-source data in the inverse analysis. Given the advantages of SWENet, it may find broad applications where full wave fields get involved to infer heterogeneous mechanical properties, such as identifying small solid tumors with ultrasound SWE, and differentiating gray and white matters of the brain with magnetic resonance elastography.
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Caiaffa CD, Ambekar YS, Singh M, Lin YL, Wlodarczyk B, Aglyamov SR, Scarcelli G, Larin KV, Finnell RH. Disruption of Fuz in mouse embryos generates hypoplastic hindbrain development and reduced cranial nerve ganglia. Dev Dyn 2024. [PMID: 38501709 DOI: 10.1002/dvdy.702] [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: 12/08/2023] [Revised: 02/07/2024] [Accepted: 02/20/2024] [Indexed: 03/20/2024] Open
Abstract
BACKGROUND The brain and spinal cord formation is initiated in the earliest stages of mammalian pregnancy in a highly organized process known as neurulation. Environmental or genetic interferences can impair neurulation, resulting in clinically significant birth defects known collectively as neural tube defects. The Fuz gene encodes a subunit of the CPLANE complex, a macromolecular planar polarity effector required for ciliogenesis. Ablation of Fuz in mouse embryos results in exencephaly and spina bifida, including dysmorphic craniofacial structures due to defective cilia formation and impaired Sonic Hedgehog signaling. RESULTS We demonstrate that knocking Fuz out during embryonic mouse development results in a hypoplastic hindbrain phenotype, displaying abnormal rhombomeres with reduced length and width. This phenotype is associated with persistent reduction of ventral neuroepithelial stiffness in a notochord adjacent area at the level of the rhombomere 5. The formation of cranial and paravertebral ganglia is also impaired in these embryos. CONCLUSIONS This study reveals that hypoplastic hindbrain development, identified by abnormal rhombomere morphology and persistent loss of ventral neuroepithelial stiffness, precedes exencephaly in Fuz ablated murine mutants, indicating that the gene Fuz has a critical function sustaining normal neural tube development and neuronal differentiation.
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Affiliation(s)
- Carlo Donato Caiaffa
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin Dell Medical School, Austin, Texas, USA
| | - Yogeshwari S Ambekar
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Ying Linda Lin
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA
| | - Bogdan Wlodarczyk
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA
| | - Salavat R Aglyamov
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | - Kirill V Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
| | - Richard H Finnell
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Cellular Biology, Molecular and Human Genetics and Medicine, Baylor College of Medicine, Houston, Texas, USA
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17
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Salahshoor H, Ortiz M. Application of Data-Driven computing to patient-specific prediction of the viscoelastic response of human brain under transcranial ultrasound stimulation. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01830-w. [PMID: 38499911 DOI: 10.1007/s10237-024-01830-w] [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: 08/20/2023] [Accepted: 02/09/2024] [Indexed: 03/20/2024]
Abstract
We present a class of model-free Data-Driven solvers that effectively enable the utilization of in situ and in vivo imaging data directly in full-scale calculations of the mechanical response of the human brain to sonic and ultrasonic stimulation, entirely bypassing the need for analytical modeling or regression of the data. The well-posedness of the approach and its convergence with respect to data are proven analytically. We demonstrate the approach, including its ability to make detailed spatially resolved patient-specific predictions of wave patterns, using public-domain MRI images, MRE data and commercially available solid-mechanics software.
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Affiliation(s)
- Hossein Salahshoor
- Department of Civil and Environmental Engineering, Duke University, Durham, NC, 27708, USA.
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA.
| | - Michael Ortiz
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, 91125, USA
- Hausdorff Center for Mathematics, University of Bonn, Bonn, 53115, Germany
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18
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Karki P, Murphy MC, Cogswell PM, Senjem ML, Graff-Radford J, Elder BD, Perry A, Graffeo CS, Meyer FB, Jack CR, Ehman RL, Huston J. Prediction of Surgical Outcomes in Normal Pressure Hydrocephalus by MR Elastography. AJNR Am J Neuroradiol 2024; 45:328-334. [PMID: 38272572 DOI: 10.3174/ajnr.a8108] [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: 07/24/2023] [Accepted: 11/21/2023] [Indexed: 01/27/2024]
Abstract
BACKGROUND AND PURPOSE Normal pressure hydrocephalus is a treatable cause of dementia associated with distinct mechanical property signatures in the brain as measured by MR elastography. In this study, we tested the hypothesis that specific anatomic features of normal pressure hydrocephalus are associated with unique mechanical property alterations. Then, we tested the hypothesis that summary measures of these mechanical signatures can be used to predict clinical outcomes. MATERIALS AND METHODS MR elastography and structural imaging were performed in 128 patients with suspected normal pressure hydrocephalus and 44 control participants. Patients were categorized into 4 subgroups based on their anatomic features. Surgery outcome was acquired for 68 patients. Voxelwise modeling was performed to detect regions with significantly different mechanical properties between each group. Mechanical signatures were summarized using pattern analysis and were used as features to train classification models and predict shunt outcomes for 2 sets of feature spaces: a limited 2D feature space that included the most common features found in normal pressure hydrocephalus and an expanded 20-dimensional (20D) feature space that included features from all 4 morphologic subgroups. RESULTS Both the 2D and 20D classifiers performed significantly better than chance for predicting clinical outcomes with estimated areas under the receiver operating characteristic curve of 0.66 and 0.77, respectively (P < .05, permutation test). The 20D classifier significantly improved the diagnostic OR and positive predictive value compared with the 2D classifier (P < .05, permutation test). CONCLUSIONS MR elastography provides further insight into mechanical alterations in the normal pressure hydrocephalus brain and is a promising, noninvasive method for predicting surgical outcomes in patients with normal pressure hydrocephalus.
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Affiliation(s)
- Pragalv Karki
- From the Department of Radiology (P.K., M.C.M., P.M.C., M.L.S., J.G.-R., C.R.J., R.L.E., J.H.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Matthew C Murphy
- From the Department of Radiology (P.K., M.C.M., P.M.C., M.L.S., J.G.-R., C.R.J., R.L.E., J.H.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Petrice M Cogswell
- From the Department of Radiology (P.K., M.C.M., P.M.C., M.L.S., J.G.-R., C.R.J., R.L.E., J.H.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Matthew L Senjem
- From the Department of Radiology (P.K., M.C.M., P.M.C., M.L.S., J.G.-R., C.R.J., R.L.E., J.H.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Jonathan Graff-Radford
- Department of Neurology (J.G.-R.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Benjamin D Elder
- Department of Neurologic Surgery (B.D.E., C.S.G., F.B.M.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Avital Perry
- Department of Neurosurgery (A.P.), Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
| | - Christopher S Graffeo
- Department of Neurologic Surgery (B.D.E., C.S.G., F.B.M.), Mayo Clinic College of Medicine, Rochester, Minnesota
- Department of Neurosurgery (C.S.G.), University of Oklahoma, Oklahoma City, Oklahoma
| | - Fredric B Meyer
- Department of Neurologic Surgery (B.D.E., C.S.G., F.B.M.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Clifford R Jack
- From the Department of Radiology (P.K., M.C.M., P.M.C., M.L.S., J.G.-R., C.R.J., R.L.E., J.H.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Richard L Ehman
- From the Department of Radiology (P.K., M.C.M., P.M.C., M.L.S., J.G.-R., C.R.J., R.L.E., J.H.), Mayo Clinic College of Medicine, Rochester, Minnesota
| | - John Huston
- From the Department of Radiology (P.K., M.C.M., P.M.C., M.L.S., J.G.-R., C.R.J., R.L.E., J.H.), Mayo Clinic College of Medicine, Rochester, Minnesota
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19
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Bano M, Hussain T, Samels MR, Butts RJ, Kirk R, Levine BD. Cardiovascular remodelling in response to exercise training in patients after the Fontan procedure: a pilot study. Cardiol Young 2024; 34:604-613. [PMID: 37664999 DOI: 10.1017/s1047951123003153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
BACKGROUND The cardiovascular adaptations associated with structured exercise training in Fontan patients remain unknown. We hypothesised that short-term training causes cardiac remodelling and parallel improvement in maximal exercise capacity (VO2 max) in these patients. METHODS AND RESULTS Five patients, median age 19.5 (17.6-21.3) years, with a history of Fontan operation meeting inclusion/exclusion criteria, participated in a 3-month training programme designed to improve endurance. Magnetic resonance images for assessment of cardiac function, fibrosis, cardiac output, and liver elastography to assess stiffness were obtained at baseline and after training. Maximal exercise capacity (VO2 max) and cardiac output Qc (effective pulmonary blood flow) at rest and during exercise were measured (C2H2 rebreathing) at the same interval. VO2 max increased from median (IQR) 27.2 (26-28.7) to 29.6 (28.5-32.2) ml/min/kg (p = 0.04). There was an improvement in cardiac output (Qc) during maximal exercise testing from median (IQR) 10.3 (10.1-12.3) to 12.3 (10.9-14.9) l/min, but this change was variable (p = 0.14). Improvement in VO2 max correlated with an increase in ventricular mass (r = 0.95, p = 0.01), and improvement in Quality-of-life inventory (PedsQL) Cardiac scale scores for patient-reported symptoms (r = 0.90, p = 0.03) and cognitive problems (r = 0.89, p = 0.04). The correlation between VO2 max and Qc showed a positive trend but was not significant (r = 0.8, p = 0.08). No adverse cardiac or liver adaptations were noted. CONCLUSION Short-term training improved exercise capacity in this Fontan pilot without any adverse cardiac or liver adaptations. These results warrant further study in a larger population and over a longer duration of time. TRIAL REGISTRATION NUMBER NCT03263312, Unique Protocol ID: STU 122016-037; Registration Date: 18 January, 2017.
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Affiliation(s)
- Maria Bano
- Department of Pediatrics, Division of Cardiology, UT Southwestern, Dallas, TX, USA
| | - Tarique Hussain
- Department of Pediatrics, Division of Cardiology, UT Southwestern, Dallas, TX, USA
| | - Mitchel R Samels
- Institute of Exercise and Environmental Medicine, Dallas, TX, USA
| | - Ryan J Butts
- Department of Pediatrics, Division of Cardiology, UT Southwestern, Dallas, TX, USA
| | - Richard Kirk
- Department of Pediatric Cardiology and Cardiac Surgery, Ospedale Pediatrico Bambino Gesu, Rome, Itlay
| | - Benjamin D Levine
- Institute of Exercise and Environmental Medicine, Dallas, TX, USA
- Department of Internal Medicine, Division of Cardiology, UT Southwestern, Dallas, TX, USA
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20
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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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Abe R, Fukuzawa K, Yoshihara C, Tano M, Saitoh S. Comparison of spin-echo echo planar imaging and gradient-recalled echo sequences in magnetic resonance elastography of liver at 1.5T same MRI scanner. Abdom Radiol (NY) 2024; 49:694-702. [PMID: 38012395 DOI: 10.1007/s00261-023-04098-3] [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: 06/23/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 11/29/2023]
Abstract
PURPOSE Magnetic resonance elastography (MRE) is used to measure liver stiffness with gradient-recalled echo (GRE)-based and spin-echo echo planar imaging (SE-EPI)-based sequences. We compared the liver stiffness (LS) values of the two sequences on a 1.5-T MR imaging scanner. METHODS This is a retrospective study. An MRE imaging section was obtained from a horizontal section of the liver. Region of interest was drawn on the elastogram, and the mean LS and pixel values were measured and compared. The correlations between proton density fat fraction, R2* values, and biochemical data from electronic medical records were confirmed, and multivariate analysis was performed. RESULTS The mean LS values were 3.01 ± 1.78 kPa for GRE and 3.13 ± 1.57 kPa for SE-EPI, showing excellent agreement and a strong correlation between the two sequences (correlation coefficient r = 0.96). The mean pixel values were 369.5 ± 142.7 pixels for GRE and 490.1 ± 197.9 pixels for SE-EPI, showing a significant difference by the Wilcoxon rank sum test (p < 0.01). There were no LS unmeasurable cases in SE-EPI, but seven (2.5%) were unmeasurable in GRE, and multivariate analysis showed a significant difference with p < 0.001 in R2* values (mean, 92.7 Hz) for the GRE method. CONCLUSION The GRE and SE-EPI methods were comparable for LS measurements in 1.5-T liver MRE, indicating that SE-EPI MRE is more useful because GRE MRE may not measure cases with high R2* values and the region of interest tends to be smaller.
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Affiliation(s)
- Ryouna Abe
- Department of Radiological Technology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, Japan.
| | - Kei Fukuzawa
- Department of Radiological Technology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, Japan
| | - Chiharu Yoshihara
- Department of Radiological Technology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, Japan
| | - Masakatsu Tano
- Department of Radiological Technology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, Japan
| | - Satoshi Saitoh
- Department of Hepatology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, Japan
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Pavuluri K, Huston J, Ehman RL, Manduca A, Jack CR, Senjem ML, Vemuri P, Murphy MC. Associations between vascular health, brain stiffness and global cognitive function. Brain Commun 2024; 6:fcae073. [PMID: 38505229 PMCID: PMC10950054 DOI: 10.1093/braincomms/fcae073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 12/19/2023] [Accepted: 02/27/2024] [Indexed: 03/21/2024] Open
Abstract
Vascular brain injury results in loss of structural and functional connectivity and leads to cognitive impairment. Its various manifestations, including microinfarcts, microhaemorrhages and white matter hyperintensities, result in microstructural tissue integrity loss and secondary neurodegeneration. Among these, tissue microstructural alteration is a relatively early event compared with atrophy along the aging and neurodegeneration continuum. Understanding its association with cognition may provide the opportunity to further elucidate the relationship between vascular health and clinical outcomes. Magnetic resonance elastography offers a non-invasive approach to evaluate tissue mechanical properties, providing a window into the microstructural integrity of the brain. This retrospective study evaluated brain stiffness as a potential biomarker for vascular brain injury and its role in mediating the impact of vascular dysfunction on cognitive impairment. Seventy-five participants from the Mayo Clinic Study of Aging underwent brain imaging using a 3T MR imager with a spin-echo echo-planar imaging sequence for magnetic resonance elastography and T1- and T2-weighted pulse sequences. This study evaluated the effects of vascular biomarkers (white matter hyperintensities and cardiometabolic condition score) on brain stiffness using voxelwise analysis. Partial correlation analysis explored associations between brain stiffness, white matter hyperintensities, cardiometabolic condition and global cognition. Mediation analysis determined the role of stiffness in mediating the relationship between vascular biomarkers and cognitive performance. Statistical significance was set at P-values < 0.05. Diagnostic accuracy of magnetic resonance elastography stiffness for white matter hyperintensities and cardiometabolic condition was evaluated using receiver operator characteristic curves. Voxelwise linear regression analysis indicated white matter hyperintensities negatively correlate with brain stiffness, specifically in periventricular regions with high white matter hyperintensity levels. A negative association between cardiovascular risk factors and stiffness was also observed across the brain. No significant patterns of stiffness changes were associated with amyloid load. Global stiffness (µ) negatively correlated with both white matter hyperintensities and cardiometabolic condition when all other covariables including amyloid load were controlled. The positive correlation between white matter hyperintensities and cardiometabolic condition weakened and became statistically insignificant when controlling for other covariables. Brain stiffness and global cognition were positively correlated, maintaining statistical significance after adjusting for all covariables. These findings suggest mechanical alterations are associated with cognitive dysfunction and vascular brain injury. Brain stiffness significantly mediated the indirect effects of white matter hyperintensities and cardiometabolic condition on global cognition. Local cerebrovascular diseases (assessed by white matter hyperintensities) and systemic vascular risk factors (assessed by cardiometabolic condition) impact brain stiffness with spatially and statistically distinct effects. Global brain stiffness is a significant mediator between vascular disease measures and cognitive function, highlighting the value of magnetic resonance elastography-based mechanical assessments in understanding this relationship.
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Affiliation(s)
| | - John Huston
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
| | - Armando Manduca
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Clifford R Jack
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
| | - Matthew L Senjem
- Department of Information Technology, Mayo Clinic, Rochester, MN 55905, USA
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Lee HJ, Cho SB, Lee JK, Kim JS, Oh CH, Kim HJ, Yoon H, Ahn HK, Kim M, Hwang YG, Kwon HY, Hwang MJ. The feasibility of MR elastography with transpelvic vibration for localization of focal prostate lesion. Sci Rep 2024; 14:3864. [PMID: 38366042 PMCID: PMC10873507 DOI: 10.1038/s41598-024-54341-0] [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: 11/16/2023] [Accepted: 02/12/2024] [Indexed: 02/18/2024] Open
Abstract
We aimed to evaluate the feasibility of MR elastography (MRE) using a transpelvic approach. Thirty-one patients who underwent prostate MRE and had a pathological diagnosis were included in this study. MRE was obtained using a passive driver placed at the umbilicus and iliac crests. The shear stiffness, clinical data, and conventional imaging findings of prostate cancer and benign prostatic hyperplasia (BPH) were compared. Inter-reader agreements were evaluated using the intraclass coefficient class (ICC). Prostate MRE was successfully performed for all patients (100% technical success rate). Nineteen cancer and 10 BPH lesions were visualized on MRE. The mean shear stiffness of cancer was significantly higher than that of BPH (5.99 ± 1.46 kPa vs. 4.67 ± 1.54 kPa, p = 0.045). One cancer was detected on MRE but not on conventional sequences. Six tiny cancer lesions were not visualized on MRE. The mean size of cancers that were not detected on MRE was smaller than that of cancers that were visible on MRE (0.8 ± 0.3 cm vs. 2.3 ± 1.8 cm, p = 0.001). The inter-reader agreement for interpreting MRE was excellent (ICC = 0.95). Prostate MRE with transpelvic vibration is feasible without intracavitary actuators. Transpelvic prostate MRE is reliable for detecting focal lesions, including clinically significant prostate cancer and BPH.
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Affiliation(s)
- Hyo Jeong Lee
- Department of Radiology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Soo Buem Cho
- Department of Radiology, Ewha Womans University College of Medicine, Seoul, South Korea.
| | - Jeong Kyong Lee
- Department of Radiology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Jin Sil Kim
- Department of Radiology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Chang Hoon Oh
- Department of Radiology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Hyun Jin Kim
- Department of Radiology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Hana Yoon
- Department of Urology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Hyun Kyu Ahn
- Department of Urology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Myong Kim
- Department of Urology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Yeok Gu Hwang
- Department of Orthopedic Surgery, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Hye Young Kwon
- Department of Radiology, Chungnam National University College of Medicine, Daejeon, South Korea
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Ngo HHP, Andrade R, Brum J, Benech N, Chatelin S, Loumeaud A, Frappart T, Fraschini C, Nordez A, Gennisson JL. In plane quantification of in vivomuscle elastic anisotropy factor by steered ultrasound pushing beams. Phys Med Biol 2024; 69:045013. [PMID: 38262052 DOI: 10.1088/1361-6560/ad21a0] [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: 06/23/2023] [Accepted: 01/23/2024] [Indexed: 01/25/2024]
Abstract
Objective.Skeletal muscles are organized into distinct layers and exhibit anisotropic characteristics across various scales. Assessing the arrangement of skeletal muscles may provide valuable biomarkers for diagnosing muscle-related pathologies and evaluating the efficacy of clinical interventions.Approach. In this study, we propose a novel ultrafast ultrasound sequence constituted of steered pushing beams was proposed for ultrasound elastography applications in transverse isotropic muscle. Based on the propagation of the shear wave vertical mode, it is possible to fit the experimental results to retrieve in the same imaging plane, the shear modulus parallel to fibers as well as the elastic anisotropy factor (ratio of Young's moduli times the shear modulus perpendicular to fibers).Main results. The technique was demonstratedin vitroin phantoms andex vivoin fusiform beef muscles. At last, the technique was appliedin vivoon fusiform muscles (biceps brachii) and mono-pennate muscles (gastrocnemius medialis) during stretching and contraction.Significance. This novel sequence provides access to new structural and mechanical biomarkers of muscle tissue, including the elastic anisotropy factor, within the same imaging plane. Additionally, it enables the investigation of multiples parameters during muscle active and passive length changes.
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Affiliation(s)
- Ha-Hien-Phuong Ngo
- Laboratoire d'imagerie médicale multimodale, BioMaps, Université Paris Saclay, CEA, CNRS, Inserm, Orsay, France
| | - Ricardo Andrade
- Nantes Université, Mouvement - Interactions - Performance, MIP, UR 4334, F-44000 Nantes, France
| | - Javier Brum
- Laboratorio de Acústica Ultrasonora, Instituto de Física, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Nicolas Benech
- Laboratorio de Acústica Ultrasonora, Instituto de Física, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Simon Chatelin
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | - Aude Loumeaud
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | | | | | - Antoine Nordez
- Nantes Université, Mouvement - Interactions - Performance, MIP, UR 4334, F-44000 Nantes, France
- Institut Universitaire de France (IUF), Paris, France
| | - Jean-Luc Gennisson
- Laboratoire d'imagerie médicale multimodale, BioMaps, Université Paris Saclay, CEA, CNRS, Inserm, Orsay, France
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Wolf M, Darwish O, Neji R, Eder M, Sunder-Plassmann G, Heinz G, Robinson SD, Schmid AI, Moser EV, Sinkus R, Meyerspeer M. Magnetic resonance elastography resolving all gross anatomical segments of the kidney during controlled hydration. Front Physiol 2024; 15:1327407. [PMID: 38384795 PMCID: PMC10880033 DOI: 10.3389/fphys.2024.1327407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/24/2024] [Indexed: 02/23/2024] Open
Abstract
Introduction: Magnetic resonance elastography (MRE) is a non-invasive method to quantify biomechanical properties of human tissues. It has potential in diagnosis and monitoring of kidney disease, if established in clinical practice. The interplay of flow and volume changes in renal vessels, tubule, urinary collection system and interstitium is complex, but physiological ranges of in vivo viscoelastic properties during fasting and hydration have never been investigated in all gross anatomical segments simultaneously. Method: Ten healthy volunteers underwent two imaging sessions, one following a 12-hour fasting period and the second after a drinking challenge of >10 mL per kg body weight (60-75 min before the second examination). High-resolution renal MRE was performed using a novel driver with rotating eccentric mass placed at the posterior-lateral wall to couple waves (50 Hz) to the kidney. The biomechanical parameters, shear wave speed (cs in m/s), storage modulus (Gd in kPa), loss modulus (Gl in kPa), phase angle ( Υ = 2 π atan G l G d ) and attenuation (α in 1/mm) were derived. Accurate separation of gross anatomical segments was applied in post-processing (whole kidney, cortex, medulla, sinus, vessel). Results: High-quality shear waves coupled into all gross anatomical segments of the kidney (mean shear wave displacement: 163 ± 47 μm, mean contamination of second upper harmonics <23%, curl/divergence: 4.3 ± 0.8). Regardless of the hydration state, median Gd of the cortex and medulla (0.68 ± 0.11 kPa) was significantly higher than that of the sinus and vessels (0.48 ± 0.06 kPa), and consistently, significant differences were found in cs, Υ , and Gl (all p < 0.001). The viscoelastic parameters of cortex and medulla were not significantly different. After hydration sinus exhibited a small but significant reduction in median Gd by -0.02 ± 0.04 kPa (p = 0.01), and, consequently, the cortico-sinusoidal-difference in Gd increased by 0.04 ± 0.07 kPa (p = 0.05). Only upon hydration, the attenuation in vessels became lower (0.084 ± 0.013 1/mm) and differed significantly from the whole kidney (0.095 ± 0.007 1/mm, p = 0.01). Conclusion: High-resolution renal MRE with an innovative driver and well-defined 3D segmentation can resolve all renal segments, especially when including the sinus in the analysis. Even after a prolonged hydration period the approach is sensitive to small hydration-related changes in the sinus and in the cortico-sinusoidal-difference.
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Affiliation(s)
- Marcos Wolf
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Omar Darwish
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Michael Eder
- Department of Medicine III, Division of Nephrology and Dialysis, General Hospital and Medical University of Vienna, Vienna, Austria
| | - Gere Sunder-Plassmann
- Department of Medicine III, Division of Nephrology and Dialysis, General Hospital and Medical University of Vienna, Vienna, Austria
| | - Gertraud Heinz
- Institut für Diagnostische und Interventionelle Radiologie, Universitätsklinikum St. Pölten, Sankt Pölten, Austria
| | - Simon Daniel Robinson
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Centre of Advanced Imaging, University of Queensland, Brisbane, QLD, Australia
| | - Albrecht Ingo Schmid
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ewald V. Moser
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ralph Sinkus
- Institut National de La Santé et de La Recherche Médicale, U1148, Laboratory for Vascular Translational Science, Paris, France
| | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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Lu JY. Modulation of Point Spread Function for Super-Resolution Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2024; 71:153-171. [PMID: 37988211 DOI: 10.1109/tuffc.2023.3335883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
High image resolution is desired in wave-related areas such as ultrasound, acoustics, optics, and electromagnetics. However, the spatial resolution of an imaging system is limited by the spatial frequency of the point spread function (PSF) of the system due to diffraction. In this article, the PSF is modulated in amplitude, phase, or both to increase the spatial frequency to reconstruct super-resolution images of objects or wave sources/fields, where the modulator can be a focused shear wave produced remotely by, for example, a radiation force from a focused Bessel beam or X-wave, or can be a small particle manipulated remotely by a radiation-force (such as acoustic and optical tweezers) or electrical and magnetic forces. A theory of the PSF-modulation method was developed, and computer simulations and experiments were conducted. The result of an ultrasound experiment shows that a pulse-echo (two-way) image reconstructed has a super-resolution (0.65 mm) as compared to the diffraction limit (2.65 mm) using a 0.5-mm-diameter modulator at 1.483-mm wavelength, and the signal-to-noise ratio (SNR) of the image was about 31 dB. If the minimal SNR of a "visible" image is 3, the resolution can be further increased to about 0.19 mm by decreasing the size of the modulator. Another ultrasound experiment shows that a wave source was imaged (one-way) at about 30-dB SNR using the same modulator size and wavelength above. The image clearly separated two 0.5-mm spaced lines, which gives a 7.26-fold higher resolution than that of the diffraction limit (3.63 mm). Although, in theory, the method has no limit on the highest achievable image resolution, in practice, the resolution is limited by noises. Also, a PSF-weighted super-resolution imaging method based on the PSF-modulation method was developed. This method is easier to implement but may have some limitations. Finally, the methods above can be applied to imaging systems of an arbitrary PSF and can produce 4-D super-resolution images. With a proper choice of a modulator (e.g., a quantum dot) and imaging system, nanoscale (a few nanometers) imaging is possible.
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Lee SW, Huang DQ, Bettencourt R, Ajmera V, Tincopa M, Noureddin N, Amangurbanova M, Siddiqi H, Madamba E, Majzoub AM, Nayfeh T, Tamaki N, Izumi N, Nakajima A, Yoneda M, Idilman R, Gumussoy M, Oz DK, Erden A, Loomba R. Low liver fat in non-alcoholic steatohepatitis-related significant fibrosis and cirrhosis is associated with hepatocellular carcinoma, decompensation and mortality. Aliment Pharmacol Ther 2024; 59:80-88. [PMID: 37968251 PMCID: PMC10807727 DOI: 10.1111/apt.17783] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/03/2023] [Accepted: 10/13/2023] [Indexed: 11/17/2023]
Abstract
BACKGROUND Progression to cirrhosis in non-alcoholic steatohepatitis (NASH) is associated with a decrease in liver fat. However, the prognostic significance of liver fat content in NASH-related significant fibrosis and cirrhosis is unclear. AIM To investigate the risk of decompensation, hepatocellular carcinoma (HCC) and mortality stratified by liver fat content in NASH-related significant fibrosis and cirrhosis. METHODS In this meta-analysis of individual participant data, 456 patients with both magnetic resonance elastography (MRE) and MRI-derived protein density fat fraction (MRI-PDFF) were enrolled, and 296 patients with longitudinal follow-up were analysed. MRE combined with fibrosis-4 (MEFIB-index), and MRI-PDFF were used to measure liver fibrosis and fat, respectively. MEFIB-negative, MEFIB-positive+ MRI-PDFF ≥5% and MEFIB-positive+ MRI-PDFF <5% were defined as no significant liver fibrosis, NASH with significant fibrosis and higher liver fat content, and NASH with significant fibrosis and low liver fat content groups, respectively. The primary outcome was hepatic decompensation, HCC and death. RESULTS The rates of decompensation, HCC and mortality were highest in the NASH with significant fibrosis and low liver fat group (33%, 17% and 17%, respectively), followed by the NASH with significant fibrosis and higher liver fat group (18%, 13% and 13% respectively), and lowest in the no significant fibrosis (MEFIB-negative) group (0%, 1% and 2% respectively). In multivariable-adjusted analysis, low liver fat content was strongly associated (HR = 42.2 [95% CI: 7.5-235.5, p < 0.0001]) with HCC, decompensation and death. Sensitivity analyses for patients with cirrhosis (MRE ≥5 kPa) determined consistent findings. CONCLUSIONS Low liver fat content in patients with burnt-out NASH-related significant fibrosis and cirrhosis is associated with an increase in hepatic decompensation, HCC and mortality.
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Affiliation(s)
- Sung Won Lee
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
- Division of Hepatology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Daniel Q. Huang
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ricki Bettencourt
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
| | - Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
- Division of Gastroenterology, University of California at San Diego, La Jolla, California, USA
| | - Monica Tincopa
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
- Division of Gastroenterology, University of California at San Diego, La Jolla, California, USA
| | - Nabil Noureddin
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
- Division of Gastroenterology, University of California at San Diego, La Jolla, California, USA
| | - Maral Amangurbanova
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
| | - Harris Siddiqi
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
| | - Egbert Madamba
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
| | - Abdul M. Majzoub
- Evidence-Based Practice Center, Mayo Clinic, Rochester, Minnesota, USA
| | - Tarek Nayfeh
- Evidence-Based Practice Center, Mayo Clinic, Rochester, Minnesota, USA
| | - Nobuharu Tamaki
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan
| | - Namiki Izumi
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan
| | - Atsushi Nakajima
- Department of Gastroenterology and Hepatology, Yokohama City University, Yokohama, Japan
| | - Masato Yoneda
- Department of Gastroenterology and Hepatology, Yokohama City University, Yokohama, Japan
| | - Ramzan Idilman
- Department of Gastroenterology, Ankara University School of Medicine, Ankara, Turkey
| | - Mesut Gumussoy
- Department of Gastroenterology, Ankara University School of Medicine, Ankara, Turkey
| | - Digdem Kuru Oz
- Department of Radiology, Ankara University School of Medicine, Ankara, Turkey
| | - Ayse Erden
- Department of Radiology, Ankara University School of Medicine, Ankara, Turkey
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
- Division of Gastroenterology, University of California at San Diego, La Jolla, California, USA
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Anders M, Meyer T, Warmuth C, Pfeuffer J, Tzschaetzsch H, Herthum H, Shahryari M, Degenhardt K, Wieben O, Schmitter S, Schulz-Menger J, Schaeffter T, Braun J, Sack I. Rapid MR elastography of the liver for subsecond stiffness sampling. Magn Reson Med 2024; 91:312-324. [PMID: 37705467 DOI: 10.1002/mrm.29859] [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: 04/27/2023] [Revised: 08/18/2023] [Accepted: 08/19/2023] [Indexed: 09/15/2023]
Abstract
PURPOSE Depicting the stiffness of biological soft tissues, MR elastography (MRE) has a wide range of diagnostic applications. The purpose of this study was to improve the temporal resolution of 2D hepatic MRE in order to provide more rapid feedback on the quality of the wavefield and ensure better temporal sampling of respiration-induced stiffness changes. METHODS We developed a rapid MRE sequence that uses 2D segmented gradient-echo spiral readout to encode 40 Hz harmonic vibrations and generate stiffness maps within 625 ms. We demonstrate the use of this technique as a rapid test for shear wave amplitudes and overall MRE image quality and as a method for monitoring respiration-induced stiffness changes in the liver in comparison to 3D MRE and ultrasound-based time-harmonic elastography. RESULTS Subsecond MRE allowed monitoring of increasing shear wave amplitudes in the liver with increasing levels of external stimulation within a single breath-hold. Furthermore, the technique detected respiration-induced changes in liver stiffness with peak values (1.83 ± 0.22 m/s) at end-inspiration, followed by softer values during forced abdominal pressure (1.60 ± 0.22 m/s) and end-expiration (1.49 ± 0.22 m/s). The effects of inspiration and expiration were confirmed by time-harmonic elastography. CONCLUSION Our results suggest that subsecond MRE of the liver is useful for checking MRE driver settings and monitoring breathing-induced changes in liver stiffness in near real time.
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Affiliation(s)
- Matthias Anders
- Department of Radiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tom Meyer
- Department of Radiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Carsten Warmuth
- Department of Radiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Josef Pfeuffer
- Application Development, Siemens Healthcare GmbH, Erlangen, Germany
| | - Heiko Tzschaetzsch
- Department of Radiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Helge Herthum
- Berlin Center for Advanced Neuroimaging (BCAN), Berlin, Germany, Corporate Member of Freie Universität Berlin, Berlin Institute of Health 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
| | - Katja Degenhardt
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Berlin, Germany
| | - Oliver Wieben
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Berlin, Germany
| | - Jeanette Schulz-Menger
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Working Group On CMR, Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and the Charité-Universitätsmedizin Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Department of Cardiology and Nephrology, HELIOS Hospital Berlin-Buch, Berlin, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Berlin, Germany
- Department of Medical Engineering, Technische Universität Berlin, Einstein Centre Digital Future, Berlin, Germany
| | - Juergen 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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29
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Ruffenach L, Heintz D, Villette C, Cosentino C, Funfschilling D, Bodin F, Bahlouli N, Chatelin S. Ultrasonic elastography for the prevention of breast implant rupture: Detection of an increase with stiffness over implantation time. J Biomech 2024; 163:111955. [PMID: 38266533 DOI: 10.1016/j.jbiomech.2024.111955] [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: 08/17/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 01/26/2024]
Abstract
Breast implants are widely used after breast cancer resection and must be changed regularly to avoid a rupture. To date, there are no quantitative criteria to help this decision. The mechanical evolution of the gels and membranes of the implants is still underinvestigated, although it can lead to early rupture. In this study, 35 breast explants having been implanted in patients for up to 17 years were characterized by ex vivo measurements of their mechanical properties. Using Acoustic Radiation Force Impulse (ARFI) ultrasound elastography, an imaging method for non-destructive mechanical characterization, an increase in the stiffness of the explants has been observed. This increase was correlated with the implantation duration, primarily after 8 years of implantation. With an increase of the shear modulus of up to a factor of nearly 3, the loss of flexibility of the implants is likely to lead to a significant increase of their risk of rupture. A complementary analysis of the gel from the explants by mass spectrometry imaging (MSI) and liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) confirms the presence of metabolites of cholesterol originating from the breast tissues, which most likely crossed the membrane of the implants and most likely degrades the gel. By observing the consequences of the physical-chemical mechanisms at work within patients, this study shows that ultrasound elastography could be used in vivoas a quantitative indicator of the risk of breast implant rupture and help diagnose their replacement.
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Affiliation(s)
- Laetitia Ruffenach
- ICube, UMR 7357 CNRS, University of Strasbourg, Strasbourg, France; Service de chirurgie plastique esthétique et reconstructrice, Hautepierre hospital, CHRU Strasbourg, HUS, Strasbourg, France
| | - Dimitri Heintz
- Plant Imaging & Mass Spectrometry (PIMS), IBMP, UPR 2357 CNRS, University of Strasbourg, Strasbourg, France
| | - Claire Villette
- Plant Imaging & Mass Spectrometry (PIMS), IBMP, UPR 2357 CNRS, University of Strasbourg, Strasbourg, France
| | | | | | - Frédéric Bodin
- ICube, UMR 7357 CNRS, University of Strasbourg, Strasbourg, France; Service de chirurgie plastique esthétique et reconstructrice, Hautepierre hospital, CHRU Strasbourg, HUS, Strasbourg, France
| | - Nadia Bahlouli
- ICube, UMR 7357 CNRS, University of Strasbourg, Strasbourg, France
| | - Simon Chatelin
- ICube, UMR 7357 CNRS, University of Strasbourg, Strasbourg, France
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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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31
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Ahmed ANA. Preoperative Magnetic Resonance Elastography (MRE) of Skull Base Tumours: A Review. Indian J Otolaryngol Head Neck Surg 2023; 75:4173-4178. [PMID: 37974805 PMCID: PMC10645913 DOI: 10.1007/s12070-023-03955-3] [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: 02/28/2023] [Accepted: 06/08/2023] [Indexed: 11/19/2023] Open
Abstract
Conventional magnetic resonance imaging (MRI) can detect tumors consistency, but it can't predict tumor stiffness or adherence of the tumor to nearby structures. Magnetic resonance elastography (MRE) is a known non-invasive MRI based imaging technique used to assess the viscoelasticity of the tissues particularly liver fibrosis. This study discussed the importance of preoperative MRE in skull base tumors and the future implications of this new imaging modality. We did review of the English literature (by searching PubMed) regarding the use of MRE in preoperative assessment of skull base tumours stiffness and adherence to surrounding tissues. Recent research demonstrated that MRE can detect the stiffness and adherence of skull base tumors to surrounding structures by recording the spread of mechanical waves in the different tissues. In addition to non-radiation exposure, this technique is fast and can be incorporated into the conventional (MRI) study. MRE can palpate skull base tumours by imaging, allowing the stiffness of the tumour to be assessed. Preoperative assessment of brain tumours consistency, stiffness, and adherence to surrounding tissues is critical to avoid injury of important nearby structures and better preoperative patient counselling regarding surgical approach (endoscopic or open), operative time, and suspected surgical complications. However, the accuracy of MRE is less in small and highly vascular tumors. Also, MRE can't accurately detect tumour-brain adherence, but the new modality (slip-interface imaging) can. Hence, adding MRE to the conventional MRI study may help in preoperative diagnosis and treatment of skull base tumours.
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Affiliation(s)
- Ahmed Nabil Abdelhamid Ahmed
- Department of Otorhinolaryngology, Faculty of Medicine, Ain Shams University, 6th Nile Valley Street, Hadayek Alkoba, Cairo, 11331 Egypt
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Zhu Y, Shi J, Alvarez-arenas TEG, Li C, Wang H, Cai H, Zhang D, He X, Wu X. Supershear Rayleigh wave imaging for quantitative assessment of biomechanical properties of brain using air-coupled optical coherence elastography. APL Bioeng 2023; 7:046107. [PMID: 37915751 PMCID: PMC10618026 DOI: 10.1063/5.0160213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/12/2023] [Indexed: 11/03/2023] Open
Abstract
Recently, supershear Rayleigh waves (SRWs) have been proposed to characterize the biomechanical properties of soft tissues. The SRWs propagate along the surface of the medium, unlike surface Rayleigh waves, SRWs propagate faster than bulk shear waves. However, their behavior and application in biological tissues is still elusive. In brain tissue elastography, shear waves combined with magnetic resonance elastography or ultrasound elastography are generally used to quantify the shear modulus, but high spatial resolution elasticity assessment in 10 μm scale is still improving. Here, we develop an air-coupled ultrasonic transducer for noncontact excitation of SRWs and Rayleigh waves in brain tissue, use optical coherent elastography (OCE) to detect, and reconstruct the SRW propagation process; in combing with a derived theoretical model of SRWs on a free boundary surface, we quantify the shear modulus of brain tissue with high spatial resolution. We first complete validation experiments using a homogeneous isotropic agar phantom, and the experimental results clearly show the SRW is 1.9649 times faster than the bulk shear waves. Furthermore, the propagation velocity of SRWs in both the frontal and parietal lobe regions of the brain is all 1.87 times faster than the bulk shear wave velocity. Finally, we evaluated the anisotropy in different brain regions, and the medulla oblongata region had the highest anisotropy index. Our study shows that the OCE system using the SRW model is a new potential approach for high-resolution assessment of the biomechanical properties of brain tissue.
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Affiliation(s)
| | - Jiulin Shi
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Tomas E. Gomez Alvarez-arenas
- Ultrasonic and Sensors Technologies Department, Information and Physical Technologies Institute, Spanish National Research Council, Serrano 144, 28006 Madrid, Spain
| | - Chenxi Li
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Haohao Wang
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Hongling Cai
- School of Physics, Nanjing University, Nanjing 210093, China
| | - Dong Zhang
- School of Physics, Nanjing University, Nanjing 210093, China
| | - Xingdao He
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Xiaoshan Wu
- School of Physics, Nanjing University, Nanjing 210093, China
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Wang C, Zhu J, Ma J, Meng X, Ma Z, Fan F. Optical coherence elastography and its applications for the biomechanical characterization of tissues. JOURNAL OF BIOPHOTONICS 2023; 16:e202300292. [PMID: 37774137 DOI: 10.1002/jbio.202300292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/19/2023] [Accepted: 09/27/2023] [Indexed: 10/01/2023]
Abstract
The biomechanical characterization of the tissues provides significant evidence for determining the pathological status and assessing the disease treatment. Incorporating elastography with optical coherence tomography (OCT), optical coherence elastography (OCE) can map the spatial elasticity distribution of biological tissue with high resolution. After the excitation with the external or inherent force, the tissue response of the deformation or vibration is detected by OCT imaging. The elastogram is assessed by stress-strain analysis, vibration amplitude measurements, and quantification of elastic wave velocities. OCE has been used for elasticity measurements in ophthalmology, endoscopy, and oncology, improving the precision of diagnosis and treatment of disease. In this article, we review the OCE methods for biomechanical characterization and summarize current OCE applications in biomedicine. The limitations and future development of OCE are also discussed during its translation to the clinic.
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Affiliation(s)
- Chongyang Wang
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | | | - Jiawei Ma
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Xiaochen Meng
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Zongqing Ma
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Fan Fan
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
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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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Krehl K, Hahndorf J, Stolzenburg N, Taupitz M, Braun J, Sack I, Schnorr J, Guo J. Characterization of renal fibrosis in rats with chronic kidney disease by in vivo tomoelastography. NMR IN BIOMEDICINE 2023; 36:e5003. [PMID: 37455558 DOI: 10.1002/nbm.5003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023]
Abstract
Chronic kidney disease (CKD) is characterized by structural changes, such as tubular atrophy, renal fibrosis, and glomerulosclerosis, all of which affect the viscoelastic properties of biological tissues. However, detection of renal viscoelasticity changes because diagnostic markers by in vivo elastography lack histopathological validation through animal models. Therefore, we investigated in vivo multiparametric magnetic resonance imaging (mp-MRI), including multifrequency magnetic resonance elastography-based tomoelastography, in the kidneys of 10 rats with adenine-induced CKD and eight healthy controls. Kidney volume (in mm3 ), water diffusivity (apparent diffusion coefficient [ADC] in mm2 /s), shear wave speed (SWS; in m/s; related to stiffness), and wave penetration rate (PR; in m/s; related to inverse viscosity) were quantified by mp-MRI and correlated with histopathologically determined renal fibrosis (collagen area fraction [CAF]; in %). Kidney volume (40% ± 29%, p = 0.009), SWS (11% ± 12%, p = 0.016), and PR (20% ± 15%, p = 0.004) were significantly increased in CKD, which was accompanied by ADC (-24% ± 27%, p = 0.02). SWS, PR, and ADC were correlated with CAF with R = 0.63, 0.75, and -0.5 (all p < 0.05), respectively. In the CKD rats, histopathology showed tubule dilation due to adenine crystal deposition. Collectively, our results suggest that collagen accumulation during CKD progression transforms soft-compliant renal tissue into a more rigid-solid state with reduced water mobility. We hypothesized that tubule dilation-a specific feature of our model-might lead to higher intraluminal pressure, which could also contribute to elevated renal stiffness. Tomoelastography is a promising tool for noninvasively assessing disease progression, detecting biomechanical properties that are sensitive to different pathologic features of CKD.
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Affiliation(s)
- Karolina Krehl
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Veterinary Pathology, College of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Julia Hahndorf
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Nicola Stolzenburg
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Matthias Taupitz
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jörg Schnorr
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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36
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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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37
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Pagé G, Bied M, Garteiser P, Van Beers B, Etaix N, Fraschini C, Bel-Brunon A, Gennisson JL. Comparison of ultrasound elastography, magnetic resonance elastography and finite element model to quantify nonlinear shear modulus. Phys Med Biol 2023; 68:205003. [PMID: 37703895 DOI: 10.1088/1361-6560/acf98c] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/13/2023] [Indexed: 09/15/2023]
Abstract
Objective. The aim of this study is to validate the estimation of the nonlinear shear modulus (A) from the acoustoelasticity theory with two experimental methods, ultrasound (US) elastography and magnetic resonance elastography (MRE), and a finite element method.Approach. Experiments were performed on agar (2%)-gelatin (8%) phantom considered as homogeneous, elastic and isotropic. Two specific setups were built to ensure a uniaxial stress step by step on the phantom, one for US and a nonmagnetic version for MRE. The stress was controlled identically in both imaging techniques, with a water tank placed on the top of the phantom and filled with increasing masses of water during the experiment. In US, the supersonic shear wave elastography was implemented on an ultrafast US device, driving a 6 MHz linear array to measure shear wave speed. In MRE, a gradient-echo sequence was used in which the three spatial directions of a 40 Hz continuous wave displacement generated with an external driver were encoded successively. Numerically, a finite element method was developed to simulate the propagation of the shear wave in a uniaxially stressed soft medium.Main results. Similar shear moduli were estimated at zero stress using experimental methods,μ0US= 12.3 ± 0.3 kPa andμ0MRE= 11.5 ± 0.7 kPa. Numerical simulations were set with a shear modulus of 12 kPa and the resulting nonlinear shear modulus was found to be -58.1 ± 0.7 kPa. A very good agreement between the finite element model and the experimental models (AUS= -58.9 ± 9.9 kPa andAMRE= -52.8 ± 6.5 kPa) was obtained.Significance. These results show the validity of such nonlinear shear modulus measurement quantification in shear wave elastography. This work paves the way to develop nonlinear elastography technique to get a new biomarker for medical diagnosis.
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Affiliation(s)
- Gwenaël Pagé
- BioMaps, Laboratoire d'Imagerie Biomédicale Multimodale, Université Paris-Saclay, CEA, CNRS UMR 9011, Inserm UMR 1281, Service hospitalier Frédéric Joliot, F-91401 Orsay, France
| | - Marion Bied
- BioMaps, Laboratoire d'Imagerie Biomédicale Multimodale, Université Paris-Saclay, CEA, CNRS UMR 9011, Inserm UMR 1281, Service hospitalier Frédéric Joliot, F-91401 Orsay, France
| | - Philippe Garteiser
- Laboratory of imaging biomarkers, Center for Research on inflammation, UMR 1149, Université Paris-Cité, Inserm, F-75018 Paris, France
| | - Bernard Van Beers
- Laboratory of imaging biomarkers, Center for Research on inflammation, UMR 1149, Université Paris-Cité, Inserm, F-75018 Paris, France
- Department of Radiology, Beaujon university hospital Paris Nord, AP-HP, F-92110 Clichy, France
| | - Nicolas Etaix
- Hologic - Supersonic Imagine, F-13290 Aix en Provence, France
| | | | - Aline Bel-Brunon
- Univ Lyon, INSA Lyon, CNRS, LaMCoS, UMR5259, F-69621 Villeurbanne, France
| | - Jean-Luc Gennisson
- BioMaps, Laboratoire d'Imagerie Biomédicale Multimodale, Université Paris-Saclay, CEA, CNRS UMR 9011, Inserm UMR 1281, Service hospitalier Frédéric Joliot, F-91401 Orsay, France
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38
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Choquet K, Vappou J, Cabras P, Ishak O, Gangi A, Breton E. Magnetic Resonance Acoustic Radiation Force Imaging (MR-ARFI) for the monitoring of High Intensity Focused Ultrasound (HIFU) ablation in anisotropic tissue. MAGMA (NEW YORK, N.Y.) 2023; 36:737-747. [PMID: 36723689 DOI: 10.1007/s10334-023-01062-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We introduce a non-invasive MR-Acoustic Radiation Force Imaging (ARFI)-based elastography method that provides both the local shear modulus and temperature maps for the monitoring of High Intensity Focused Ultrasound (HIFU) therapy. MATERIALS AND METHODS To take tissue anisotropy into account, the local shear modulus μ is determined in selected radial directions around the focal spot by fitting the phase profiles to a linear viscoelastic model, including tissue-specific mechanical relaxation time τ. MR-ARFI was evaluated on a calibrated phantom, then applied to the monitoring of HIFU in a gel phantom, ex vivo and in vivo porcine muscle tissue, in parallel with MR-thermometry. RESULTS As expected, the shear modulus polar maps reflected the isotropy of phantoms and the anisotropy of muscle. In the HIFU monitoring experiments, both the shear modulus polar map and the thermometry map were updated with every pair of MR-ARFI phase images acquired with opposite MR-ARFI-encoding. The shear modulus was found to decrease (phantom and ex vivo) or increase (in vivo) during heating, before remaining steady during the cooling phase. The mechanical relaxation time, estimated pre- and post-HIFU, was found to vary in muscle tissue. DISCUSSION MR-ARFI allowed for monitoring of viscoelasticity changes around the HIFU focal spot even in anisotropic muscle tissue.
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Affiliation(s)
- Karine Choquet
- Université de Strasbourg, CNRS, ICube, UMR 7357, Strasbourg, France.
| | - Jonathan Vappou
- Université de Strasbourg, CNRS, ICube, UMR 7357, Strasbourg, France
| | - Paolo Cabras
- Université de Strasbourg, CNRS, ICube, UMR 7357, Strasbourg, France
- Image Guided Therapy, Pessac, France
| | - Ounay Ishak
- Université de Strasbourg, CNRS, ICube, UMR 7357, Strasbourg, France
| | - Afshin Gangi
- Université de Strasbourg, CNRS, ICube, UMR 7357, Strasbourg, France
- Department of Interventional Imaging, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Elodie Breton
- Université de Strasbourg, CNRS, ICube, UMR 7357, Strasbourg, France.
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Yoneda M, Nakajima A. The role of MRI technology in liver evaluation for NAFLD patients: Advancements and opportunities. Hepatology 2023; 78:1020-1022. [PMID: 37212150 DOI: 10.1097/hep.0000000000000478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 05/15/2023] [Indexed: 05/23/2023]
Affiliation(s)
- Masato Yoneda
- Department of Gastroenterology and Hepatology, Yokohama City University Hospital, Yokohama, Japan
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40
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Tsujita Y, Sofue K, Ueshima E, Ueno Y, Hori M, Murakami T. Clinical Application of Quantitative MR Imaging in Nonalcoholic Fatty Liver Disease. Magn Reson Med Sci 2023; 22:435-445. [PMID: 35584952 PMCID: PMC10552668 DOI: 10.2463/mrms.rev.2021-0152] [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: 11/29/2021] [Accepted: 03/23/2022] [Indexed: 11/09/2022] Open
Abstract
Viral hepatitis was previously the most common cause of chronic liver disease. However, in recent years, nonalcoholic fatty liver disease (NAFLD) cases have been increasing, especially in developed countries. NAFLD is histologically characterized by fat, fibrosis, and inflammation in the liver, eventually leading to cirrhosis and hepatocellular carcinoma. Although biopsy is the gold standard for the assessment of the liver parenchyma, quantitative evaluation methods, such as ultrasound, CT, and MRI, have been reported to have good diagnostic performances. The quantification of liver fat, fibrosis, and inflammation is expected to be clinically useful in terms of the prognosis, early intervention, and treatment response for the management of NAFLD. The aim of this review was to discuss the basics and prospects of MRI-based tissue quantifications of the liver, mainly focusing on proton density fat fraction for the quantification of fat deposition, MR elastography for the quantification of fibrosis, and multifrequency MR elastography for the evaluation of inflammation.
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Affiliation(s)
- Yushi Tsujita
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Keitaro Sofue
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Eisuke Ueshima
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Yoshiko Ueno
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Masatoshi Hori
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Takamichi Murakami
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
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41
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Davis ZR, Gossett PC, Wilson RL, Kim W, Mei Y, Butz KD, Emery NC, Nauman EA, Avril S, Neu CP, Chan DD. Intervertebral Disc Elastography to Relate Shear Modulus and Relaxometry in Compression and Bending. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555817. [PMID: 37732250 PMCID: PMC10508717 DOI: 10.1101/2023.09.01.555817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Intervertebral disc degeneration is the most recognized cause of low back pain, characterized by the decline of tissue structure and mechanics. Image-based mechanical parameters (e.g., strain, stiffness) may provide an ideal assessment of disc function that is lost with degeneration but unfortunately remains underdeveloped. Moreover, it is unknown whether strain or stiffness of the disc may be predicted by MRI relaxometry (e.g. T1 or T2), an increasingly accepted quantitative measure of disc structure. In this study, we quantified T1 and T2 relaxation times and in-plane strains using displacement-encoded MRI within the disc under physiological levels of compression and bending. We then estimated shear modulus in orthogonal image planes and compared these values to relaxation times and strains within regions of the disc. Intratissue strain depended on the loading mode, and shear modulus in the nucleus pulposus was typically an order of magnitude lower than the annulus fibrosis, except in bending, where the apparent stiffness depended on the loading. Relative shear moduli estimated from strain data derived under compression generally did not correspond with those from bending experiments, with no correlations in the sagittal plane and only 4 of 15 regions correlated in the coronal plane, suggesting that future inverse models should incorporate multiple loading conditions. Strain imaging and strain-based estimation of material properties may serve as imaging biomarkers to distinguish healthy and diseased discs. Additionally, image-based elastography and relaxometry may be viewed as complementary measures of disc structure and function to assess degeneration in longitudinal studies.
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Affiliation(s)
- Zachary R. Davis
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Paull C. Gossett
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Robert L. Wilson
- Paul M. Rady Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
| | - Woong Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Yue Mei
- State Key Laboratory of Structural Analysis for Industrial Equipment and International Research Center for Computational Mechanics, Department of Engineering Mechanics, Dalian University of Technology, Dalian, China
- Mines Saint-Étienne, Université Jean Monnet, INSERM, U 1059 Sainbiose, 42023, SaintÉtienne, France
| | - Kent D. Butz
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Nancy C. Emery
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Eric A. Nauman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Stéphane Avril
- Mines Saint-Étienne, Université Jean Monnet, INSERM, U 1059 Sainbiose, 42023, SaintÉtienne, France
| | - Corey P. Neu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- Paul M. Rady Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
- Biomedical Engineering Program, University of Colorado, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado, Boulder, CO, USA
| | - Deva D. Chan
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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Kalwa PL, Schäffer TE. Water flow elastography - A promising tool to measure tissue stiffness during minimally invasive surgery. J Mech Behav Biomed Mater 2023; 145:106004. [PMID: 37418969 DOI: 10.1016/j.jmbbm.2023.106004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 07/09/2023]
Abstract
Mechanical properties are important markers for pathological processes in tissue. Elastography techniques are therefore becoming more and more useful for diagnostics. In minimally invasive surgery (MIS), however, the probe size is limited and the handling is restricted, thereby excluding the application of most established elastography techniques. In this paper we introduce water flow elastography (WaFE) as a new technique that benefits from a small and inexpensive probe. This probe flows pressurized water against the sample surface to locally indent it. The volume of the indentation is measured with a flow meter. We use finite element simulations to find the relation between the indentation volume, the water pressure, and the Young's modulus of the sample. We used WaFE to measure the Young's modulus of silicone samples and porcine organs, finding agreement within 10% to measurements with a commercial material testing machine. Our results show that WaFE is a promising technique for providing local elastography in MIS.
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Affiliation(s)
- Paul L Kalwa
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - Tilman E Schäffer
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany.
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Obrzut M, Atamaniuk V, Ehman RL, Yin M, Cholewa M, Gutkowski K, Domka W, Ozga D, Obrzut B. Evaluation of Spleen Stiffness in Young Healthy Volunteers Using Magnetic Resonance Elastography. Diagnostics (Basel) 2023; 13:2738. [PMID: 37685274 PMCID: PMC10486410 DOI: 10.3390/diagnostics13172738] [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: 07/19/2023] [Revised: 08/16/2023] [Accepted: 08/20/2023] [Indexed: 09/10/2023] Open
Abstract
PURPOSE Magnetic resonance elastography (MRE) has been established as the most accurate noninvasive technique for diagnosing liver fibrosis. Recent publications have suggested that the measurement of splenic stiffness is useful in setting where portal hypertension may be present. The goal of the current study was to compile normative data for MRE-assessed stiffness measurements of the spleen in young adults. MATERIALS AND METHODS A total of 100 healthy young Caucasian volunteers (65 females and 35 males) in the age range of 20 to 32 years were enrolled in this study. The participants reported no history of chronic spleen and liver disease, normal alcohol consumption, and a normal diet. The MRE data were acquired by using a 1.5 T whole-body scanner and a 2D GRE pulse sequence with 60 Hz excitation. Spleen stiffness was calculated as a weighted mean of stiffness values in the regions of interest manually drawn by the radiologist on three to five spleen slices. RESULTS Mean spleen stiffness was 5.09 ± 0.65 kPa for the whole group. Male volunteers had slightly higher splenic stiffness compared to females: 5.28 ± 0.78 vs. 4.98 ± 0.51 kPa, however, this difference was not statistically significant (p = 0.12). Spleen stiffness did not correlate with spleen fat content and liver stiffness but a statistically significant correlation with spleen volume was found. CONCLUSIONS The findings of this study provide normative values for 2D MRE-based measurement of spleen stiffness in young adults, a basis for assessing the value of this biomarker in young patients with portal system pathologies.
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Affiliation(s)
- Marzanna Obrzut
- Institute of Health Sciences, Medical College, University of Rzeszow, Warzywna 1a, 35-310 Rzeszow, Poland; (M.O.)
| | - Vitaliy Atamaniuk
- Department of Biophysics, Institute of Physics, College of Natural Sciences, University of Rzeszow, Prof. Stanisława Pigonia Str. 1, 35-310 Rzeszow, Poland; (V.A.); (M.C.)
| | - Richard L. Ehman
- Department of Radiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Meng Yin
- Department of Radiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Marian Cholewa
- Department of Biophysics, Institute of Physics, College of Natural Sciences, University of Rzeszow, Prof. Stanisława Pigonia Str. 1, 35-310 Rzeszow, Poland; (V.A.); (M.C.)
| | - Krzysztof Gutkowski
- Institute of Medical Sciences, Medical College, University of Rzeszow, Rejtana 16C, 35-959 Rzeszow, Poland;
| | - Wojciech Domka
- Department of Otolaryngology, Institute of Medical Sciences, Medical College, University of Rzeszow, Rejtana 16C, 35-959 Rzeszow, Poland;
| | - Dorota Ozga
- Institute of Health Sciences, Medical College, University of Rzeszow, Warzywna 1a, 35-310 Rzeszow, Poland; (M.O.)
| | - Bogdan Obrzut
- Department of Obstetrics and Gynecology, Institute of Medical Sciences, Medical College, University of Rzeszow, Rejtana 16C, 35-959 Rzeszow, Poland
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Caiaffa CD, Ambekar YS, Singh M, Lin YL, Wlodarczyk B, Aglyamov SR, Scarcelli G, Larin KV, Finnell R. Disruption of Fuz in mouse embryos generates hypoplastic hindbrain development and reduced cranial nerve ganglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.04.552068. [PMID: 37577618 PMCID: PMC10418252 DOI: 10.1101/2023.08.04.552068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The formation of the brain and spinal cord is initiated in the earliest stages of mammalian pregnancy in a highly organized process known as neurulation. Convergent and extension movements transforms a flat sheet of ectodermal cells into a narrow and elongated line of neuroepithelia, while a major source of Sonic Hedgehog signaling from the notochord induces the overlying neuroepithelial cells to form two apposed neural folds. Afterward, neural tube closure occurs by synchronized coordination of the surface ectoderm and adjacent neuroepithelial walls at specific axial regions known as neuropores. Environmental or genetic interferences can impair neurulation resulting in neural tube defects. The Fuz gene encodes a subunit of the CPLANE complex, which is a macromolecular planar polarity effector required for ciliogenesis. Ablation of Fuz in mouse embryos results in exencephaly and spina bifida, including dysmorphic craniofacial structures due to defective cilia formation and impaired Sonic Hedgehog signaling. In this work, we demonstrate that knocking Fuz out during embryonic mouse development results in a hypoplastic hindbrain phenotype, displaying abnormal rhombomeres with reduced length and width. This phenotype is associated with persistent loss of ventral neuroepithelial stiffness, in a notochord adjacent area at the level of the rhombomere 5, preceding the development of exencephaly in Fuz ablated mutants. The formation of cranial and paravertebral ganglia is also impaired in these embryos, indicating that Fuz has a critical function sustaining normal neural tube development and neuronal differentiation. SIGNIFICANCE STATEMENT Neural tube defects (NTDs) are a common cause of disability in children, representing the second most common congenital structural malformation in humans following only congenital cardiovascular malformations. NTDs affect approximately 1 to 2 pregnancies per 1000 births every year worldwide, when the mechanical forces folding the neural plate fails to close at specific neuropores located anteriorly (cranial) or posteriorly (caudal) along the neural tube, in a process known as neurulation, which happens throughout the third and fourth weeks of human pregnancy.
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Liu D, Chen J, Zhang Y, Dai Y, Yao X. Magnetic resonance elastography-derived stiffness: potential imaging biomarker for differentiation of benign and malignant pancreatic masses. Abdom Radiol (NY) 2023; 48:2604-2614. [PMID: 37237155 DOI: 10.1007/s00261-023-03956-4] [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: 03/21/2023] [Revised: 05/06/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023]
Abstract
OBJECTIVE This study sought to determine the diagnostic performance of magnetic resonance elastography (MRE) for pancreatic solid masses, compared with diffusion-weighted imaging (DWI) and serum CA19-9, to establish a threshold for differentiating between pancreatic ductal adenocarcinoma (PDAC) and benign tumors in pancreas. MATERIALS AND METHODS Between July 2021 to January 2023, 75 adult patients confirmed with pancreatic solid tumors were enrolled in this prospective and consecutive study. All patients underwent MRE and DWI examinations that were both performed with a spin echo-EPI sequence. Stiffness maps and apparent diffusion coefficient (ADC) maps were generated, with MRE-derived mass stiffness and stiffness ratio (computing as the ratio of mass stiffness to the parenchyma stiffness) and DWI-derived ADC values obtained by placing regions of interest over the focal tumors on stiffness and ADC maps. Further analysis of comparing diagnostic performances was assessed by calculating the area under ROC curves. RESULTS PDAC had significantly higher tumor stiffness [3.795 (2.879-4.438) kPa vs. 2.359 (2.01-3.507) kPa, P = 0.0003], stiffness ratio [1.939 (1.562-2.511) vs. 1.187 (1.031-1.453), P < 0.0001] and serum CA19-9 level [276 (31.73-1055) vs. 10.45 (7.825-14.15), P < 0.0001] than other pancreatic masses. Mass stiffness, stiffness ratio and serum CA19-9 showed good diagnostic performance for differentiation with AUC of 0.7895, 0.8392 and 0.9136 respectively. The sensitivity/specificity/positive predictive value/negative predictive value for differentiating malignant from benign pancreatic tumors with mass stiffness (cutoff, > 2.8211 kPa) and stiffness ratio (cutoff, > 1.5117) were 78.4/66.7/82.9/60% and 77.8/83.3/90.3/65.2% respectively. The combined performance of Mass stiffness, stiffness ratio and serum CA19-9 got an AUC of 0.9758. CONCLUSION MRE holds excellent clinical potential in discriminating pancreatic ductal adenocarcinoma from other pancreatic solid masses according to their mechanical properties.
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Affiliation(s)
- Dingxia Liu
- Shanghai Institute of Medical Imaging, Fudan University, Shanghai, China
- Department of Radiology, Zhongshan Hospital of Fudan University, Shanghai, China
| | - Jiejun Chen
- Shanghai Institute of Medical Imaging, Fudan University, Shanghai, China
- Department of Radiology, Zhongshan Hospital of Fudan University, Shanghai, China
| | - Yunfei Zhang
- Shanghai Institute of Medical Imaging, Fudan University, Shanghai, China
- MR Collaboration, Central Research Institute, United Imaging Healthcare, Shanghai, China
| | - Yongming Dai
- MR Collaboration, Central Research Institute, United Imaging Healthcare, Shanghai, China
| | - Xiuzhong Yao
- Shanghai Institute of Medical Imaging, Fudan University, Shanghai, China.
- Department of Radiology, Zhongshan Hospital of Fudan University, Shanghai, China.
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Abstract
ABSTRACT The mechanical traits of cancer include abnormally high solid stress as well as drastic and spatially heterogeneous changes in intrinsic mechanical tissue properties. Whereas solid stress elicits mechanosensory signals promoting tumor progression, mechanical heterogeneity is conducive to cell unjamming and metastatic spread. This reductionist view of tumorigenesis and malignant transformation provides a generalized framework for understanding the physical principles of tumor aggressiveness and harnessing them as novel in vivo imaging markers. Magnetic resonance elastography is an emerging imaging technology for depicting the viscoelastic properties of biological soft tissues and clinically characterizing tumors in terms of their biomechanical properties. This review article presents recent technical developments, basic results, and clinical applications of magnetic resonance elastography in patients with malignant tumors.
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Affiliation(s)
- Jing Guo
- From the Department of Radiology
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Kailash KA, Guertler CA, Johnson CL, Okamoto RJ, Bayly PV. Measurement of relative motion of the brain and skull in the mini-pig in-vivo. J Biomech 2023; 156:111676. [PMID: 37329640 PMCID: PMC11086683 DOI: 10.1016/j.jbiomech.2023.111676] [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: 07/19/2022] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/19/2023]
Abstract
The mechanical role of the skull-brain interface is critical to the pathology of concussion and traumatic brain injury (TBI) and may evolve with age. Here we characterize the skull-brain interface in juvenile, female Yucatan mini-pigs from 3 to 6 months old using techniques from magnetic resonance elastography (MRE). The displacements of the skull and brain were measured by a motion-sensitive MR imaging sequence during low-amplitude harmonic motion of the head. Each animal was scanned four times at 1-month intervals. Harmonic motion at 100 Hz was excited by three different configurations of a jaw actuator in order to vary the direction of loading. Rigid-body linear motions of the brain and skull were similar, although brain rotations were consistently smaller than corresponding skull rotations. Relative displacements between the brain and skull were estimated for voxels on the surface of the brain. Amplitudes of relative displacements between skull and brain were 1-3 μm, approximately 25-50% of corresponding skull displacements. Maps of relative displacement showed variations by anatomical region, and the normal component of relative displacement was consistently 25-50% of the tangential component. These results illuminate the mechanics of the skull-brain interface in a gyrencephalic animal model relevant to human brain injury and development.
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Affiliation(s)
- Keshav A Kailash
- Washington University in St. Louis, Biomedical Engineering, United States
| | - Charlotte A Guertler
- Washington University in St. Louis, Mechanical Engineering and Material Science, United States
| | | | - Ruth J Okamoto
- Washington University in St. Louis, Mechanical Engineering and Material Science, United States
| | - Philip V Bayly
- Washington University in St. Louis, Biomedical Engineering, United States; Washington University in St. Louis, Mechanical Engineering and Material Science, United States.
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Hatt A, Lloyd R, Bolsterlee B, Bilston LE. Strain-dependent shear properties of human adipose tissue in vivo. J Mech Behav Biomed Mater 2023; 143:105924. [PMID: 37276651 DOI: 10.1016/j.jmbbm.2023.105924] [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: 05/14/2023] [Accepted: 05/20/2023] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Human adipose tissue (fat) deforms substantially under normal physiological loading and during impact. Thus, accurate data on strain-dependent stiffness of fat is essential for the creation of accurate biomechanical models. Previous studies on ex vivo samples reported human fat to be nonlinear and viscoelastic. When static compression is combined with magnetic resonance (MR) elastography (an imaging technique used to measure viscoelasticity in vivo), the large deformation properties of tissues can be determined. Here, we use magnetic resonance elastography to quantify fat shear modulus in vivo under increasing compressive strain and compare it to the underlying passive gluteal muscle. METHODS The right buttocks of ten female participants were incrementally compressed at four levels while MR elastography (50 Hz) and mDixon images were acquired. Maps of tissue shear modulus (G*) were reconstructed from the MR elastography phase images. Tissue strain was estimated from registration of deformed and undeformed mDixon images. Linear mixed models were fit to the natural logarithm of the compressive strain and shear modulus data for each tissue. RESULTS Shear modulus increased in an exponential relationship with compressive strain in fat: Gfat*=748.5*Cyy-1.18Pa, and to a lesser extent in muscle: Gmuscle*=956.4*Cyy-0.36Pa. The baseline (undeformed) stiffness of fat was significantly lower than that of muscle (mean G*fat = 752 Pa, mean G*muscle = 1000 Pa, paired samples t-test, t = -4.24, p = 0.001). However, fat exhibited a significantly higher degree of strain dependence (characterised by the exponent of the curve, t = -6.47, p = 0.0001). CONCLUSION Static compression of human adipose tissue results in an increase in apparent viscoelastic shear modulus (stiffness), in an exponentially increasing relationship. The relationships defined here can be used in the development of physiologically realistic computational models for impact, injury and biomechanical modelling.
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Affiliation(s)
- Alice Hatt
- Neuroscience Research Australia, PO Box 1165, Randwick, NSW, 2031, Australia
| | - Robert Lloyd
- Neuroscience Research Australia, PO Box 1165, Randwick, NSW, 2031, Australia; University of New South Wales, Faculty of Medicine & Health, 18 High St, Kensington, NSW, 2052, Australia
| | - Bart Bolsterlee
- Neuroscience Research Australia, PO Box 1165, Randwick, NSW, 2031, Australia; University of New South Wales, Graduate School of Biomedical Engineering, Library Rd, Kensington, NSW, 2033, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, PO Box 1165, Randwick, NSW, 2031, Australia; University of New South Wales, Faculty of Medicine & Health, 18 High St, Kensington, NSW, 2052, Australia.
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Mohammed S, Kozlowski P, Salcudean S. Phase-regularized and displacement-regularized compressed sensing for fast magnetic resonance elastography. NMR IN BIOMEDICINE 2023; 36:e4899. [PMID: 36628624 DOI: 10.1002/nbm.4899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/12/2022] [Accepted: 01/01/2023] [Indexed: 06/15/2023]
Abstract
Liver magnetic resonance elastography (MRE) is a noninvasive stiffness measurement technique that captures the tissue displacement in the phase of the signal. To limit the scanning time to a single breath-hold, liver MRE usually involves advanced readout techniques such as simultaneous multislice (SMS) or multishot methods. Furthermore, all these readout techniques require additional in-plane acceleration using either parallel imaging capabilities, such as sensitivity encoding (SENSE), or k -space undersampling, such as compressed sensing (CS). However, these methods apply a single regularization function on the complex image. This study aims to design and evaluate methods that use separate regularization on the magnitude and phase of MRE to exploit their distinct spatiotemporal characteristics. Specifically, we introduce two compressed sensing methods. The first method, termed phase-regularized compressed sensing (PRCS), applies a two-dimensional total variation (TV) prior to the magnitude and two-dimensional wavelet regularization to the phase. The second method, termed displacement-regularized compressed sensing (DRCS), exploits the spatiotemporal redundancy using 3D total variation on the magnitude. Additionally, DRCS includes a displacement fitting function to apply wavelet regularization to the displacement phasor. Both DRCS and PRCS were evaluated with different levels of compression factors in three datasets: an in silico abdomen dataset, an in vitro tissue-mimicking phantom, and an in vivo liver dataset. The reconstructed images were compared with the full sampled reconstruction, zero-filling reconstruction, wavelet-regularized compressed sensing, and a low rank plus sparse reconstruction. The metrics used for quantitative evaluation were the structural similarity index (SSIM) of magnitude (M-SSIM), displacement (D-SSIM), and shear modulus (S-SSIM), and mean shear modulus. Results from highly undersampled in silico and in vitro datasets demonstrate that the DRCS method provides higher reconstruction quality than the conventional compressed sensing method for a wide range of stiffness values. Notably, DRCS provides 24% and 22% increase in D-SSIM compared with CS for the in silico and in vitro datasets, respectively. Comparison with liver stiffness measured from full sampled data and highly undersampled data (CR=4) demonstrates that the DRCS method provided the strongest correlation ( R 2 =0.95), second-lowest mean bias (-0.18 kPa, lowest for CS with -0.16 kPa), and lowest coefficient of variation (CV=3.6%). Our results demonstrate the potential of using DRCS to improve the reconstruction quality of accelerated MRE.
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Affiliation(s)
- Shahed Mohammed
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada
| | - Piotr Kozlowski
- Department of Radiology, University of British Columbia, Vancouver, Canada
| | - Septimiu Salcudean
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada
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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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