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Jerban S, Ma Y, Dorthe EW, Kakos L, Le N, Alenezi S, Sah RL, Chang EY, D'Lima D, Du J. Assessing cortical bone mechanical properties using collagen proton fraction from ultrashort echo time magnetization transfer (UTE-MT) MRI modeling. Bone Rep 2019; 11:100220. [PMID: 31440531 PMCID: PMC6700521 DOI: 10.1016/j.bonr.2019.100220] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 08/02/2019] [Indexed: 12/19/2022] Open
Abstract
Cortical bone shows as a signal void when using conventional clinical magnetic resonance imaging (MRI). Ultrashort echo time MRI (UTE-MRI) can acquire high signal from cortical bone, thus enabling quantitative assessments. Magnetization transfer (MT) imaging combined with UTE-MRI can indirectly assess protons in the organic matrix of bone. This study aimed to examine UTE-MT MRI techniques to estimate the mechanical properties of cortical bone. A total of 156 rectangular human cortical bone strips were harvested from the tibial and femoral midshafts of 43 donors (62 ± 22 years old, 62 specimens from females, 94 specimens from males). Bone specimens were scanned using UTE-MT sequences on a clinical 3 T MRI scanner and on a micro-computed tomography (μCT) scanner. A series of MT pulse saturation powers (400°, 600°, 800°) and frequency offsets (2, 5, 10, 20, 50 kHz) was used to measure the macromolecular fraction (MMF) utilizing a two-pool MT model. Failure mechanical properties of the bone specimens were measured using 4-point bending tests. MMF from MRI results showed significant strong correlations with cortical bone porosity (R = -0.72, P < 0.01) and bone mineral density (BMD) (R = +0.71, P < 0.01). MMF demonstrated significant moderate correlations with Young modulus, yield stress, and ultimate stress (R = 0.60-0.61, P < 0.01). These results suggest that the two-pool UTE-MT model focusing on the organic matrix of bone can potentially serve as a novel tool to detect the variations of bone mechanical properties and intracortical porosity.
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Key Words
- 3D, three-dimensional
- 3D-UTE, three-dimensional ultrashort echo time imaging
- BMD, bone mineral density
- Bone microstructure
- CT, computed tomography
- Cortical bone
- DEXA, dual-energy X-ray absorptiometry
- FA, flip angle
- FOV, field of view
- MMF, macromolecular proton fraction
- MR, magnetic resonance
- MRI
- MRI, magnetic resonance imaging
- MT, magnetization transfer
- Magnetization transfer
- Mechanical properties
- PBS, phosphate-buffered saline
- RF, radio frequency
- ROI, region of interest
- T2MM, macromolecular T2
- TE, echo time
- TR, repetition time
- Ultrashort echo time
- μCT, micro-computed tomography
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, CA 92093, USA
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, CA 92093, USA
| | - Erik W Dorthe
- Shiley Center for Orthopedic Research and Education at Scripps Clinic, La Jolla, CA 92037, USA
| | - Lena Kakos
- Department of Radiology, University of California, San Diego, CA 92093, USA
| | - Nicole Le
- Radiology Service, VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Salem Alenezi
- Research and Laboratories Sector, Saudi Food and Drug Authority, Riyadh 3292, Saudi Arabia
| | - Robert L Sah
- Department of Bioengineering, University of California, San Diego, CA 92093, USA.,Department of Orthopaedic Surgery, University of California, San Diego, CA 92093, USA
| | - Eric Y Chang
- Radiology Service, VA San Diego Healthcare System, San Diego, CA 92161, USA.,Department of Radiology, University of California, San Diego, CA 92093, USA
| | - Darryl D'Lima
- Shiley Center for Orthopedic Research and Education at Scripps Clinic, La Jolla, CA 92037, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA 92093, USA
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Abstract
Brain edema is a common feature associated with hepatic encephalopathy (HE). In patients with acute HE, brain edema has been shown to play a crucial role in the associated neurological deterioration. In chronic HE, advanced magnetic resonance imaging (MRI) techniques have demonstrated that low-grade brain edema appears also to be an important pathological feature. This review explores the different methods used to measure brain edema ex vivo and in vivo in animal models and in humans with chronic HE. In addition, an in-depth description of the main studies performed to date is provided. The role of brain edema in the neurological alterations linked to HE and whether HE and brain edema are the manifestations of the same pathophysiological mechanism or two different cerebral manifestations of brain dysfunction in liver disease are still under debate. In vivo MRI/magnetic resonance spectroscopy studies have allowed insight into the development of brain edema in chronic HE. However, additional in vivo longitudinal and multiparametric/multimodal studies are required (in humans and animal models) to elucidate the relationship between liver function, brain metabolic changes, cellular changes, cell swelling, and neurological manifestations in chronic HE.
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Key Words
- 1H MRS, proton magnetic resonance spectroscopy
- ADC, apparent diffusion coefficient
- ALF, acute liver failure
- AQP, aquaporins
- BBB, blood-brain barrier
- BDL, bile duct ligation
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Cr, creatine
- DTI, diffusion tensor imaging
- DWI, diffusion-weighted imaging
- FLAIR, fluid-attenuated inversion recovery
- GM, gray matter
- Gln, glutamine
- Glx, sum of glutamine and glutamate
- HE, hepatic encephalopathy
- Ins, inositol
- LPS, lipopolysaccharide
- Lac, lactate
- MD, mean diffusivity
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- MT, magnetization transfer
- MTR, MT ratio
- NMR, nuclear magnetic resonance
- PCA, portocaval anastomosis
- TE, echo time
- WM, white matter
- brain edema
- chronic hepatic encephalopathy
- in vivo magnetic resonance imaging
- in vivo magnetic resonance spectroscopy
- liver cirrhosis
- mIns, myo-inositol
- tCho, total choline
- tCr, total creatine
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Affiliation(s)
- Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland,Address for correspondence: Cristina Cudalbu, Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL-CIBM, Office F3 628, Station 6, CH-1015 Lausanne, Switzerland.
| | - Simon D. Taylor-Robinson
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, St Mary's Hospital Campus, Imperial College London, London, United Kingdom
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Seif M, Curt A, Thompson AJ, Grabher P, Weiskopf N, Freund P. Quantitative MRI of rostral spinal cord and brain regions is predictive of functional recovery in acute spinal cord injury. Neuroimage Clin 2018; 20:556-563. [PMID: 30175042 PMCID: PMC6115607 DOI: 10.1016/j.nicl.2018.08.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 07/11/2018] [Accepted: 08/17/2018] [Indexed: 10/28/2022]
Abstract
Objective To reveal the immediate extent of trauma-induced neurodegenerative changes rostral to the level of lesion and determine the predictive clinical value of quantitative MRI (qMRI) following acute spinal cord injury (SCI). Methods Twenty-four acute SCI patients and 23 healthy controls underwent a high-resolution T1-weighted protocol. Eighteen of those patients and 20 of controls additionally underwent a multi-parameter mapping (MPM) MRI protocol sensitive to the content of tissue structure, including myelin and iron. Patients were examined clinically at baseline, 2, 6, 12, and 24 months post-SCI. We assessed volume and microstructural changes in the spinal cord and brain using T1-weighted MRI, magnetization transfer (MT), longitudinal relaxation rate (R1), and effective transverse relaxation rate (R2*) maps. Regression analysis determined associations between acute qMRI parameters and recovery. Results At baseline, cord area and its anterior-posterior width were decreased in patients, whereas MT, R1, and R2* parameters remained unchanged in the cord. Within the cerebellum, volume decrease was paralleled by increases of MT and R2* parameters. Early grey matter changes were observed within the primary motor cortex and limbic system. Importantly, early volume and microstructural changes of the cord and cerebellum predicted functional recovery following injury. Conclusions Neurodegenerative changes rostral to the level of lesion occur early in SCI, with varying temporal and spatial dynamics. Early qMRI markers of spinal cord and cerebellum are predictive of functional recovery. These neuroimaging biomarkers may supplement clinical assessments and provide insights into the potential of therapeutic interventions to enhance neural plasticity.
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Key Words
- APW, anterior posterior width
- Acute micro-structural changes
- Brain and spinal cord atrophy
- ISNCSCI, international standards for the neurological classification of spinal cord injury
- LRW, left right width
- MPM, multi-parameter mapping
- MT, magnetization transfer
- PD*, effective proton density
- Quantitative neuroimaging
- R1, longitudinal relaxation rate
- R2*, effective transverse relaxation rate
- ROI, region of interest
- SCA, spinal cord area
- SCI, spinal cord injury
- SCIM, spinal cord independence measure
- Spinal cord injury
- VBCT, voxel based cortical thickness
- VBM, voxel based morphometry
- VBQ, voxel based quantification
- Voxel-based morphometry and quantification
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Affiliation(s)
- Maryam Seif
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Armin Curt
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland
| | - Alan J Thompson
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK
| | - Patrick Grabher
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, UK
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, UK.
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Naumova AV, Akulov AE, Khodanovich MY, Yarnykh VL. High-resolution three-dimensional quantitative map of the macromolecular proton fraction distribution in the normal rat brain. Data Brief 2016; 10:381-384. [PMID: 28018953 PMCID: PMC5176127 DOI: 10.1016/j.dib.2016.11.066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/12/2016] [Accepted: 11/17/2016] [Indexed: 11/30/2022] Open
Abstract
The presented dataset provides a normative high-resolution three-dimensional (3D) macromolecular proton fraction (MPF) map of the healthy rat brain in vivo and source images used for its reconstruction. The images were acquired using the protocol described elsewhere (Naumova, et al. High-resolution three-dimensional macromolecular proton fraction mapping for quantitative neuroanatomical imaging of the rodent brain in ultra-high magnetic fields. Neuroimage (2016) doi: 10.1016/j.neuroimage.2016.09.036). The map was reconstructed from three source images with different contrast weightings (proton density, T1, and magnetization transfer) using the single-point algorithm with a synthetic reference image. Source images were acquired from a living animal on an 11.7 T small animal MRI scanner with isotropic spatial resolution of 170 µm3 and total acquisition time about 1.5 h. The 3D dataset can be used for multiple purposes including interactive viewing of rat brain anatomy, measurements of reference MPF values in various brain structures, and development of image processing techniques for the rodent brain segmentation. It also can serve as a gold standard image for implementation and optimization of rodent brain MRI protocols.
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Affiliation(s)
- Anna V Naumova
- University of Washington, Department of Radiology, 850 Republican St., Seattle, WA, USA; National Research Tomsk State University, Research Institute of Biology and Biophysics, 36 Lenina Ave, Tomsk, Russia
| | - Andrey E Akulov
- Institute of Cytology and Genetics, The Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, Novosibirsk, Russia
| | - Marina Yu Khodanovich
- National Research Tomsk State University, Research Institute of Biology and Biophysics, 36 Lenina Ave, Tomsk, Russia
| | - Vasily L Yarnykh
- University of Washington, Department of Radiology, 850 Republican St., Seattle, WA, USA; National Research Tomsk State University, Research Institute of Biology and Biophysics, 36 Lenina Ave, Tomsk, Russia
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Abstract
Hepatic encephalopathy is a brain alteration associated to liver failure that produces cognitive impairments at long term. Neuroimaging are non-invasive methods for the study of the brain by means of spectroscopy and imaging techniques. These technologies give huge information about cerebral metabolism and water distribution to explore brain pathways involved in the pathogenesis of hepatic encephalopathy. Furthermore, new magnetic resonance implementations such as voxel-based morphometry or resting-state functional magnetic resonance imaging allow studying brain atrophy and neuronal connectivity of the cerebral network involved in the neurocognitive impairments observed in the patients. The development of magnetic resonance technology will generate handy tools for the brain study of liver failure to elucidate the time-course of the pathology and thus to obtain an early diagnosis of cerebral complications.
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Key Words
- ADC, apparent diffusion coefficient
- CFF, critical flicker frequency
- HE, hepatic encephalopathy
- MR, magnetic resonance
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- MT, magnetization transfer
- MTR, magnetization transfer ratio
- NAA, N-acetyl aspartate
- PHES, psychometric hepatic encephalopathy score
- VBM, voxel-based morphometry
- fMRI, functional magnetic resonance imaging
- hepatic encephalopathy
- imaging
- magnetic resonance
- spectroscopy
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Affiliation(s)
- Laia Chavarria
- Liver Unit, Hospital Vall Hebron, Barcelona, Spain,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain,Departament Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Juan Cordoba
- Liver Unit, Hospital Vall Hebron, Barcelona, Spain,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain,Departament Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain,Address for correspondence: Juan Córdoba, Hospital Universitari Vall d'Hebron, Passeig Vall d'Hebron 119-129, Barcelona 08035, Spain. Tel.: +34 932476140; fax: +34 932476068.
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