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Stys PK, Tsutsui S, Gafson AR, ‘t Hart BA, Belachew S, Geurts JJG. New views on the complex interplay between degeneration and autoimmunity in multiple sclerosis. Front Cell Neurosci 2024; 18:1426231. [PMID: 39161786 PMCID: PMC11330826 DOI: 10.3389/fncel.2024.1426231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 06/14/2024] [Indexed: 08/21/2024] Open
Abstract
Multiple sclerosis (MS) is a frequently disabling neurological disorder characterized by symptoms, clinical signs and imaging abnormalities that typically fluctuate over time, affecting any level of the CNS. Prominent lymphocytic inflammation, many genetic susceptibility variants involving immune pathways, as well as potent responses of the neuroinflammatory component to immunomodulating drugs, have led to the natural conclusion that this disease is driven by a primary autoimmune process. In this Hypothesis and Theory article, we discuss emerging data that cast doubt on this assumption. After three decades of therapeutic experience, what has become clear is that potent immune modulators are highly effective at suppressing inflammatory relapses, yet exhibit very limited effects on the later progressive phase of MS. Moreover, neuropathological examination of MS tissue indicates that degeneration, CNS atrophy, and myelin loss are most prominent in the progressive stage, when lymphocytic inflammation paradoxically wanes. Finally, emerging clinical observations such as "progression independent of relapse activity" and "silent progression," now thought to take hold very early in the course, together argue that an underlying "cytodegenerative" process, likely targeting the myelinating unit, may in fact represent the most proximal step in a complex pathophysiological cascade exacerbated by an autoimmune inflammatory overlay. Parallels are drawn with more traditional neurodegenerative disorders, where a progressive proteopathy with prion-like propagation of toxic misfolded species is now known to play a key role. A potentially pivotal contribution of the Epstein-Barr virus and B cells in this process is also discussed.
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Affiliation(s)
- Peter K. Stys
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Shigeki Tsutsui
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Arie R. Gafson
- Biogen Digital Health, Biogen, Cambridge, MA, United States
| | - Bert A. ‘t Hart
- Department of Anatomy and Neurosciences, Amsterdam University Medical Centers (location VUmc), Amsterdam, Netherlands
| | - Shibeshih Belachew
- TheraPanacea, Paris, France
- Indivi (DBA of Healios AG), Basel, Switzerland
| | - Jeroen J. G. Geurts
- Department of Anatomy and Neurosciences, Amsterdam University Medical Centers (location VUmc), Amsterdam, Netherlands
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Gloor M, Andelova M, Gaetano L, Papadopoulou A, Burguet Villena F, Sprenger T, Radue EW, Kappos L, Bieri O, Garcia M. Longitudinal analysis of new multiple sclerosis lesions with magnetization transfer and diffusion tensor imaging. Eur Radiol 2024; 34:1680-1691. [PMID: 37658894 PMCID: PMC10873225 DOI: 10.1007/s00330-023-10173-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/02/2023] [Accepted: 07/12/2023] [Indexed: 09/05/2023]
Abstract
OBJECTIVE The potential of magnetization transfer imaging (MTI) and diffusion tensor imaging (DTI) for the detection and evolution of new multiple sclerosis (MS) lesions was analyzed. METHODS Nineteen patients with MS obtained conventional MRI, MTI, and DTI examinations bimonthly for 12 months and again after 24 months at 1.5 T MRI. MTI was acquired with balanced steady-state free precession (bSSFP) in 10 min (1.3 mm3 isotropic resolution) yielding both magnetization transfer ratio (MTR) and quantitative magnetization transfer (qMT) parameters (pool size ratio (F), exchange rate (kf), and relaxation times (T1/T2)). DTI provided fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). RESULTS At the time of their appearance on MRI, the 21 newly detected MS lesions showed significantly reduced MTR/F/kf and prolonged T1/T2 parameters, as well as significantly reduced FA and increased AD/MD/RD. Significant differences were already observed for MTR 4 months and for qMT parameters 2 months prior to lesions' detection on MRI. DTI did not show any significant pre-lesional differences. Slightly reversed trends were observed for most lesions up to 8 months after their detection for qMT and less pronounced for MTR and three diffusion parameters, while appearing unchanged on MRI. CONCLUSIONS MTI provides more information than DTI in MS lesions and detects tissue changes 2 to 4 months prior to their appearance on MRI. After lesions' detection, qMT parameter changes promise to be more sensitive than MTR for the lesions' evolutional assessment. Overall, bSSFP-based MTI adumbrates to be more sensitive than MRI and DTI for the early detection and follow-up assessment of MS lesions. CLINICAL RELEVANCE STATEMENT When additionally acquired in routine MRI, fast bSSFP-based MTI can complement the MRI/DTI longitudinal lesion assessment by detecting MS lesions 2-4 months earlier than with MRI, which could implicate earlier clinical decisions and better follow-up/treatment assessment in MS patients. KEY POINTS • Magnetization transfer imaging provides more information than DTI in multiple sclerosis lesions and can detect tissue changes 2 to 4 months prior to their appearance on MRI. • After lesions' detection, quantitative magnetization transfer changes are more pronounced than magnetization transfer ratio changes and therefore promise to be more sensitive for the lesions' evolutional assessment. • Balanced steady-state free precession-based magnetization transfer imaging is more sensitive than MRI and DTI for the early detection and follow-up assessment of multiple sclerosis lesions.
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Affiliation(s)
- Monika Gloor
- Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Michaela Andelova
- Department of Neurology, University Hospital Basel, Basel, Switzerland
- Department of Neurology and Center of Clinical Neuroscience, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Laura Gaetano
- Department of Neurology, University Hospital Basel, Basel, Switzerland
- Medical Image Analysis Center (MIAC) AG, Basel, Switzerland
- Novartis Institutes for BioMedical Research Basel, Basel, Switzerland
| | - Athina Papadopoulou
- Department of Neurology, University Hospital Basel, Basel, Switzerland
- Department of Clinical Research, Faculty of Medicine, University Hospital Basel, Basel, Switzerland
| | - Federico Burguet Villena
- Department of Neurology, University Hospital Basel, Basel, Switzerland
- Department of Clinical Research, Faculty of Medicine, University Hospital Basel, Basel, Switzerland
| | - Till Sprenger
- Department of Neurology, University Hospital Basel, Basel, Switzerland
- University Hospital Zürich, Zurich, Switzerland
| | | | - Ludwig Kappos
- Department of Neurology, University Hospital Basel, Basel, Switzerland
- Department of Clinical Research, Faculty of Medicine, University Hospital Basel, Basel, Switzerland
| | - Oliver Bieri
- Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Meritxell Garcia
- Division of Neuroradiology, Department of Radiology, University Hospital Basel, Basel, Switzerland.
- Department of Neuroradiology, University Hospital Zürich, Frauenklinikstrasse 10, 8091, Zurich, Switzerland.
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3
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Khormi I, Al-Iedani O, Alshehri A, Ramadan S, Lechner-Scott J. MR myelin imaging in multiple sclerosis: A scoping review. J Neurol Sci 2023; 455:122807. [PMID: 38035651 DOI: 10.1016/j.jns.2023.122807] [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: 07/24/2023] [Revised: 10/20/2023] [Accepted: 11/19/2023] [Indexed: 12/02/2023]
Abstract
The inability of disease-modifying therapies to stop the progression of multiple sclerosis (MS), has led to the development of a new therapeutic strategy focussing on myelin repair. While conventional MRI lacks sensitivity for quantifying myelin damage, advanced MRI techniques are proving effective. The development of targeted therapeutics requires histological validation of myelin imaging results, alongside the crucial task of establishing correlations between myelin imaging results and clinical assessments, so that the effectiveness of therapeutic interventions can be evaluated. The aims of this scoping review were to identify myelin imaging methods - some of which have been histologically validated, and to determine how these approaches correlate with clinical assessments of people with MS (pwMS), thus allowing for effective therapeutic evaluation. A search of two databases was undertaken for publications relating to studies on adults MS using either MRI/MR-histology of the MS brain in the range 1990-to-2022. The myelin imaging methods specified were relaxometry, magnetization transfer, and quantitative susceptibility. Relaxometry was used most frequently, with myelin water fraction (MWF) being the primary metric. Studies conducted on tissue from various regions of the brain showed that MWF was significantly lower in pwMS than in healthy controls. Magnetization transfer ratio indicated that the macromolecular content of lesions was lower than that of normal-appearing tissue. Higher magnetic susceptibility of lesions were indicative of myelin breakdown and iron accumulation. Several myelin imaging metrics were correlated with disability, disease severity and duration. Many studies showed a good correlation between myelin measured histologically and by MR myelin imaging techniques.
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Affiliation(s)
- Ibrahim Khormi
- School of Health Sciences, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia; Hunter Medical Research Institute, New Lambton Heights, Australia; College of Applied Medical Sciences, University of Jeddah, Jeddah, Saudi Arabia
| | - Oun Al-Iedani
- Hunter Medical Research Institute, New Lambton Heights, Australia; School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia
| | - Abdulaziz Alshehri
- School of Health Sciences, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia; Hunter Medical Research Institute, New Lambton Heights, Australia; Department of Radiology, King Fahd Hospital of the University, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Saadallah Ramadan
- School of Health Sciences, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia; Hunter Medical Research Institute, New Lambton Heights, Australia.
| | - Jeannette Lechner-Scott
- Hunter Medical Research Institute, New Lambton Heights, Australia; Department of Neurology, John Hunter Hospital, New Lambton Heights, Australia; School of Medicine and Public Health, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia
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4
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Kolb H, Al-Louzi O, Beck ES, Sati P, Absinta M, Reich DS. From pathology to MRI and back: Clinically relevant biomarkers of multiple sclerosis lesions. Neuroimage Clin 2022; 36:103194. [PMID: 36170753 PMCID: PMC9668624 DOI: 10.1016/j.nicl.2022.103194] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 12/14/2022]
Abstract
Focal lesions in both white and gray matter are characteristic of multiple sclerosis (MS). Histopathological studies have helped define the main underlying pathological processes involved in lesion formation and evolution, serving as a gold standard for many years. However, histopathology suffers from an intrinsic bias resulting from over-reliance on tissue samples from late stages of the disease or atypical cases and is inadequate for routine patient assessment. Pathological-radiological correlative studies have established advanced MRI's sensitivity to several relevant MS-pathological substrates and its practicality for assessing dynamic changes and following lesions over time. This review focuses on novel imaging techniques that serve as biomarkers of critical pathological substrates of MS lesions: the central vein, chronic inflammation, remyelination and repair, and cortical lesions. For each pathological process, we address the correlative value of MRI to MS pathology, its contribution in elucidating MS pathology in vivo, and the clinical utility of the imaging biomarker.
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Affiliation(s)
- Hadar Kolb
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA,Department of Neurology, Tel Aviv Sourasky Medical Center, Tel Aviv-Yaffo, Israel,Corresponding author at: Department of Neurology, Tel Aviv Sourasky Medical Center, Tel Aviv-Yaffo, Israel.
| | - Omar Al-Louzi
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA,Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Erin S. Beck
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA,Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Pascal Sati
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA,Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Martina Absinta
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA,Institute of Experimental Neurology (INSPE), IRCSS San Raffaele Hospital and Vita-Salute San Raffaele University, Milan, Italy,Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Daniel S. Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
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5
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York EN, Thrippleton MJ, Meijboom R, Hunt DPJ, Waldman AD. Quantitative magnetization transfer imaging in relapsing-remitting multiple sclerosis: a systematic review and meta-analysis. Brain Commun 2022; 4:fcac088. [PMID: 35652121 PMCID: PMC9149789 DOI: 10.1093/braincomms/fcac088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 12/17/2021] [Accepted: 03/31/2022] [Indexed: 11/28/2022] Open
Abstract
Myelin-sensitive MRI such as magnetization transfer imaging has been widely used in multiple sclerosis. The influence of methodology and differences in disease subtype on imaging findings is, however, not well established. Here, we systematically review magnetization transfer brain imaging findings in relapsing-remitting multiple sclerosis. We examine how methodological differences, disease effects and their interaction influence magnetization transfer imaging measures. Articles published before 06/01/2021 were retrieved from online databases (PubMed, EMBASE and Web of Science) with search terms including 'magnetization transfer' and 'brain' for systematic review, according to a pre-defined protocol. Only studies that used human in vivo quantitative magnetization transfer imaging in adults with relapsing-remitting multiple sclerosis (with or without healthy controls) were included. Additional data from relapsing-remitting multiple sclerosis subjects acquired in other studies comprising mixed disease subtypes were included in meta-analyses. Data including sample size, MRI acquisition protocol parameters, treatments and clinical findings were extracted and qualitatively synthesized. Where possible, effect sizes were calculated for meta-analyses to determine magnetization transfer (i) differences between patients and healthy controls; (ii) longitudinal change and (iii) relationships with clinical disability in relapsing-remitting multiple sclerosis. Eighty-six studies met inclusion criteria. MRI acquisition parameters varied widely, and were also underreported. The majority of studies examined the magnetization transfer ratio in white matter, but magnetization transfer metrics, brain regions examined and results were heterogeneous. The analysis demonstrated a risk of bias due to selective reporting and small sample sizes. The pooled random-effects meta-analysis across all brain compartments revealed magnetization transfer ratio was 1.17 per cent units (95% CI -1.42 to -0.91) lower in relapsing-remitting multiple sclerosis than healthy controls (z-value: -8.99, P < 0.001, 46 studies). Linear mixed-model analysis did not show a significant longitudinal change in magnetization transfer ratio across all brain regions [β = 0.12 (-0.56 to 0.80), t-value = 0.35, P = 0.724, 14 studies] or normal-appearing white matter alone [β = 0.037 (-0.14 to 0.22), t-value = 0.41, P = 0.68, eight studies]. There was a significant negative association between the magnetization transfer ratio and clinical disability, as assessed by the Expanded Disability Status Scale [r = -0.32 (95% CI -0.46 to -0.17); z-value = -4.33, P < 0.001, 13 studies]. Evidence suggests that magnetization transfer imaging metrics are sensitive to pathological brain changes in relapsing-remitting multiple sclerosis, although effect sizes were small in comparison to inter-study variability. Recommendations include: better harmonized magnetization transfer acquisition protocols with detailed methodological reporting standards; larger, well-phenotyped cohorts, including healthy controls; and, further exploration of techniques such as magnetization transfer saturation or inhomogeneous magnetization transfer ratio.
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Affiliation(s)
- Elizabeth N. York
- Centre for Clinical Brain Sciences, University of
Edinburgh, Edinburgh, UK
| | | | - Rozanna Meijboom
- Centre for Clinical Brain Sciences, University of
Edinburgh, Edinburgh, UK
| | - David P. J. Hunt
- Centre for Clinical Brain Sciences, University of
Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, University of
Edinburgh, Edinburgh, UK
- Anne Rowling Regenerative Neurology Clinic,
University of Edinburgh, Edinburgh, UK
| | - Adam D. Waldman
- Centre for Clinical Brain Sciences, University of
Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, University of
Edinburgh, Edinburgh, UK
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6
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Haacke EM, Bernitsas E, Subramanian K, Utriainen D, Palutla VK, Yerramsetty K, Kumar P, Sethi SK, Chen Y, Latif Z, Jella P, Gharabaghi S, Wang Y, Zhang X, Comley RA, Beaver J, Luo Y. A Comparison of Magnetic Resonance Imaging Methods to Assess Multiple Sclerosis Lesions: Implications for Patient Characterization and Clinical Trial Design. Diagnostics (Basel) 2021; 12:diagnostics12010077. [PMID: 35054244 PMCID: PMC8775217 DOI: 10.3390/diagnostics12010077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 11/16/2022] Open
Abstract
Magnetic resonance imaging (MRI) is a sensitive imaging modality for identifying inflammatory and/or demyelinating lesions, which is critical for a clinical diagnosis of MS and evaluating drug responses. There are many unique means of probing brain tissue status, including conventional T1 and T2 weighted imaging (T1WI, T2WI), T2 fluid attenuated inversion recovery (FLAIR), magnetization transfer, myelin water fraction, diffusion tensor imaging (DTI), phase-sensitive inversion recovery and susceptibility weighted imaging (SWI), but no study has combined all of these modalities into a single well-controlled investigation. The goals of this study were to: compare different MRI measures for lesion visualization and quantification; evaluate the repeatability of various imaging methods in healthy controls; compare quantitative susceptibility mapping (QSM) with myelin water fraction; measure short-term longitudinal changes in the white matter of MS patients and map out the tissue properties of the white matter hyperintensities using STAGE (strategically acquired gradient echo imaging). Additionally, the outcomes of this study were anticipated to aid in the choice of an efficient imaging protocol reducing redundancy of information and alleviating patient burden. Of all the sequences used, T2 FLAIR and T2WI showed the most lesions. To differentiate the putative demyelinating lesions from inflammatory lesions, the fusion of SWI and T2 FLAIR was used. Our study suggests that a practical and efficient imaging protocol combining T2 FLAIR, T1WI and STAGE (with SWI and QSM) can be used to rapidly image MS patients to both find lesions and study the demyelinating and inflammatory characteristics of the lesions.
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Affiliation(s)
- Ewart Mark Haacke
- The MRI Institute for Biomedical Research, Bingham Farms, MI 48025, USA; (D.U.); (S.K.S.)
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA; (K.S.); (Z.L.); (P.J.); (Y.W.)
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA; (E.B.); (Y.C.)
- SpinTech Inc., Bingham Farms, MI 48025, USA
- MR Innovations Inc., Bingham Farms, MI 48025, USA;
- Correspondence:
| | - Evanthia Bernitsas
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA; (E.B.); (Y.C.)
| | - Karthik Subramanian
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA; (K.S.); (Z.L.); (P.J.); (Y.W.)
| | - David Utriainen
- The MRI Institute for Biomedical Research, Bingham Farms, MI 48025, USA; (D.U.); (S.K.S.)
- SpinTech Inc., Bingham Farms, MI 48025, USA
| | - Vinay Kumar Palutla
- MR Medical Imaging Innovations India Pvt. Ltd., Hyderabad 500081, India; (V.K.P.); (K.Y.); (P.K.)
| | - Kiran Yerramsetty
- MR Medical Imaging Innovations India Pvt. Ltd., Hyderabad 500081, India; (V.K.P.); (K.Y.); (P.K.)
| | - Prashanth Kumar
- MR Medical Imaging Innovations India Pvt. Ltd., Hyderabad 500081, India; (V.K.P.); (K.Y.); (P.K.)
| | - Sean K. Sethi
- The MRI Institute for Biomedical Research, Bingham Farms, MI 48025, USA; (D.U.); (S.K.S.)
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA; (K.S.); (Z.L.); (P.J.); (Y.W.)
- SpinTech Inc., Bingham Farms, MI 48025, USA
| | - Yongsheng Chen
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA; (E.B.); (Y.C.)
| | - Zahid Latif
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA; (K.S.); (Z.L.); (P.J.); (Y.W.)
| | - Pavan Jella
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA; (K.S.); (Z.L.); (P.J.); (Y.W.)
| | | | - Ying Wang
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA; (K.S.); (Z.L.); (P.J.); (Y.W.)
- MR Innovations Inc., Bingham Farms, MI 48025, USA;
| | - Xiaomeng Zhang
- AbbVie Inc., North Chicago, IL 60064, USA; (X.Z.); (R.A.C.); (J.B.); (Y.L.)
| | - Robert A. Comley
- AbbVie Inc., North Chicago, IL 60064, USA; (X.Z.); (R.A.C.); (J.B.); (Y.L.)
| | - John Beaver
- AbbVie Inc., North Chicago, IL 60064, USA; (X.Z.); (R.A.C.); (J.B.); (Y.L.)
| | - Yanping Luo
- AbbVie Inc., North Chicago, IL 60064, USA; (X.Z.); (R.A.C.); (J.B.); (Y.L.)
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7
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Elliott C, Momayyezsiahkal P, Arnold DL, Liu D, Ke J, Zhu L, Zhu B, George IC, Bradley DP, Fisher E, Cahir-McFarland E, Stys PK, Geurts JJG, Franchimont N, Gafson A, Belachew S. Abnormalities in normal-appearing white matter from which multiple sclerosis lesions arise. Brain Commun 2021; 3:fcab176. [PMID: 34557664 PMCID: PMC8453433 DOI: 10.1093/braincomms/fcab176] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 11/24/2022] Open
Abstract
Normal-appearing white matter is far from normal in multiple sclerosis; little is known about the precise pathology or spatial pattern of this alteration and its relation to subsequent lesion formation. This study was undertaken to evaluate normal-appearing white matter abnormalities in brain areas where multiple sclerosis lesions subsequently form, and to investigate the spatial distribution of normal-appearing white matter abnormalities in persons with multiple sclerosis. Brain MRIs of pre-lesion normal-appearing white matter were analysed in participants with new T2 lesions, pooled from three clinical trials: SYNERGY (NCT01864148; n = 85 with relapsing multiple sclerosis) was the test data set; ASCEND (NCT01416181; n = 154 with secondary progressive multiple sclerosis) and ADVANCE (NCT00906399; n = 261 with relapsing-remitting multiple sclerosis) were used as validation data sets. Focal normal-appearing white matter tissue state was analysed prior to lesion formation in areas where new T2 lesions later formed (pre-lesion normal-appearing white matter) using normalized magnetization transfer ratio and T2-weighted (nT2) intensities, and compared with overall normal-appearing white matter and spatially matched contralateral normal-appearing white matter. Each outcome was analysed using linear mixed-effects models. Follow-up time (as a categorical variable), patient-level characteristics (including treatment group) and other baseline variables were treated as fixed effects. In SYNERGY, nT2 intensity was significantly higher, and normalized magnetization transfer ratio was lower in pre-lesion normal-appearing white matter versus overall and contralateral normal-appearing white matter at all time points up to 24 weeks before new T2 lesion onset. In ASCEND and ADVANCE (for which normalized magnetization transfer ratio was not available), nT2 intensity in pre-lesion normal-appearing white matter was significantly higher compared to both overall and contralateral normal-appearing white matter at all pre-lesion time points extending up to 2 years prior to lesion formation. In all trials, nT2 intensity in the contralateral normal-appearing white matter was also significantly higher at all pre-lesion time points compared to overall normal-appearing white matter. Brain atlases of normal-appearing white matter abnormalities were generated using measures of voxel-wise differences in normalized magnetization transfer ratio of normal-appearing white matter in persons with multiple sclerosis compared to scanner-matched healthy controls. We observed that overall spatial distribution of normal-appearing white matter abnormalities in persons with multiple sclerosis largely recapitulated the anatomical distribution of probabilities of T2 hyperintense lesions. Overall, these findings suggest that intrinsic spatial properties and/or longstanding precursory abnormalities of normal-appearing white matter tissue may contribute to the risk of autoimmune acute demyelination in multiple sclerosis.
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Affiliation(s)
| | - Parya Momayyezsiahkal
- NeuroRx Research, Montreal, QC H2X 3P9, Canada.,McGill University, Montreal, QC H3A 0G4, Canada
| | - Douglas L Arnold
- NeuroRx Research, Montreal, QC H2X 3P9, Canada.,McGill University, Montreal, QC H3A 0G4, Canada
| | - Dawei Liu
- Biogen Digital Health, Biogen, Cambridge, MA 02142, USA
| | - Jun Ke
- Biogen, Cambridge, MA 02142, USA
| | - Li Zhu
- Biogen, Cambridge, MA 02142, USA
| | - Bing Zhu
- Biogen, Cambridge, MA 02142, USA
| | - Ilena C George
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | | | | | - Peter K Stys
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jeroen J G Geurts
- Department of Anatomy and Neurosciences, Amsterdam UMC, 1081 HV Amsterdam, Netherlands
| | | | - Arie Gafson
- Biogen Digital Health, Biogen, Cambridge, MA 02142, USA
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8
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Sweeney EM, Nguyen TD, Kuceyeski A, Ryan SM, Zhang S, Zexter L, Wang Y, Gauthier SA. Estimation of Multiple Sclerosis lesion age on magnetic resonance imaging. Neuroimage 2020; 225:117451. [PMID: 33069865 PMCID: PMC7805079 DOI: 10.1016/j.neuroimage.2020.117451] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/02/2020] [Accepted: 10/08/2020] [Indexed: 01/17/2023] Open
Abstract
We introduce the first-ever statistical framework for estimating the age of Multiple Sclerosis (MS) lesions from magnetic resonance imaging (MRI). Estimating lesion age is an important step when studying the longitudinal behavior of MS lesions and can be used in applications such as studying the temporal dynamics of chronic active MS lesions. Our lesion age estimation models use first order radiomic features over a lesion derived from conventional T1 (T1w) and T2 weighted (T2w) and fluid attenuated inversion recovery (FLAIR), T1w with gadolinium contrast (T1w+c), and Quantitative Susceptibility Mapping (QSM) MRI sequences as well as demographic information. For this analysis, we have a total of 32 patients with 53 new lesions observed at 244 time points. A one or two step random forest model for lesion age is fit on a training set using a lesion volume cutoff of 15 mm3 or 50 mm3 . We explore the performance of nine different modeling scenarios that included various combinations of the MRI sequences and demographic information and a one or two step random forest models, as well as simpler models that only uses the mean radiomic feature from each MRI sequence. The best performing model on a validation set is a model that uses a two-step random forest model on the radiomic features from all of the MRI sequences with demographic information using a lesion volume cutoff of 50 mm3 . This model has a mean absolute error of 7.23 months (95% CI: [6.98, 13.43]) and a median absolute error of 5.98 months (95% CI: [5.26, 13.25]) in the validation set. For this model, the predicted age and actual age have a statistically significant association (p-value <0.001) in the validation set.
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Affiliation(s)
- Elizabeth M Sweeney
- Department of Population Health Sciences, Weill Cornell Medical College, New York, NY, United States.
| | - Thanh D Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States
| | - Amy Kuceyeski
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States; Brain and Mind Institute, Weill Cornell Medical College, New York, NY, United States
| | - Sarah M Ryan
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO, United States
| | - Shun Zhang
- Department of Radiology, Tongji Hospital, Wuhan, China
| | - Lily Zexter
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Yi Wang
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States
| | - Susan A Gauthier
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States; Brain and Mind Institute, Weill Cornell Medical College, New York, NY, United States; Department of Neurology, Weill Cornell Medical College, New York, NY, United States
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Bagnato F, Franco G, Ye F, Fan R, Commiskey P, Smith SA, Xu J, Dortch R. Selective inversion recovery quantitative magnetization transfer imaging: Toward a 3 T clinical application in multiple sclerosis. Mult Scler 2020; 26:457-467. [PMID: 30907234 PMCID: PMC7528886 DOI: 10.1177/1352458519833018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Assessing the degree of myelin injury in patients with multiple sclerosis (MS) is challenging due to the lack of magnetic resonance imaging (MRI) methods specific to myelin quantity. By measuring distinct tissue parameters from a two-pool model of the magnetization transfer (MT) effect, quantitative magnetization transfer (qMT) may yield these indices. However, due to long scan times, qMT has not been translated clinically. OBJECTIVES We aim to assess the clinical feasibility of a recently optimized selective inversion recovery (SIR) qMT and to test the hypothesis that SIR-qMT-derived metrics are informative of radiological and clinical disease-related changes in MS. METHODS A total of 18 MS patients and 9 age- and sex-matched healthy controls (HCs) underwent a 3.0 Tesla (3 T) brain MRI, including clinical scans and an optimized SIR-qMT protocol. Four subjects were re-scanned at a 2-week interval to determine inter-scan variability. RESULTS SIR-qMT measures differed between lesional and non-lesional tissue (p < 0.0001) and between normal-appearing white matter (NAWM) of patients with more advanced disability and normal white matter (WM) of HCs (p < 0.05). SIR-qMT measures were associated with lesion volumes, disease duration, and disability scores (p ⩽ 0.002). CONCLUSION SIR-qMT at 3 T is clinically feasible and predicts both radiological and clinical disease severity in MS.
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Affiliation(s)
- Francesca Bagnato
- Department of Neurology, Neuro-Immunology Division/Neuro-Imaging Unit, Vanderbilt University Medical Center (VUMC), Nashville, TN
| | - Giulia Franco
- Department of Neurology, Neuro-Immunology Division/Neuro-Imaging Unit, Vanderbilt University Medical Center (VUMC), Nashville, TN
- IRCCS Foundation Ca’ Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Fei Ye
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN; USA
| | - Run Fan
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN; USA
| | | | - Seth A. Smith
- Vanderbilt University Institute of Imaging Science; Nashville, TN
| | - Junzhong Xu
- Vanderbilt University Institute of Imaging Science; Nashville, TN
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN
| | - Richard Dortch
- Vanderbilt University Institute of Imaging Science; Nashville, TN
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN
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Stadelmann C, Timmler S, Barrantes-Freer A, Simons M. Myelin in the Central Nervous System: Structure, Function, and Pathology. Physiol Rev 2019; 99:1381-1431. [PMID: 31066630 DOI: 10.1152/physrev.00031.2018] [Citation(s) in RCA: 315] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocytes generate multiple layers of myelin membrane around axons of the central nervous system to enable fast and efficient nerve conduction. Until recently, saltatory nerve conduction was considered the only purpose of myelin, but it is now clear that myelin has more functions. In fact, myelinating oligodendrocytes are embedded in a vast network of interconnected glial and neuronal cells, and increasing evidence supports an active role of oligodendrocytes within this assembly, for example, by providing metabolic support to neurons, by regulating ion and water homeostasis, and by adapting to activity-dependent neuronal signals. The molecular complexity governing these interactions requires an in-depth molecular understanding of how oligodendrocytes and axons interact and how they generate, maintain, and remodel their myelin sheaths. This review deals with the biology of myelin, the expanded relationship of myelin with its underlying axons and the neighboring cells, and its disturbances in various diseases such as multiple sclerosis, acute disseminated encephalomyelitis, and neuromyelitis optica spectrum disorders. Furthermore, we will highlight how specific interactions between astrocytes, oligodendrocytes, and microglia contribute to demyelination in hereditary white matter pathologies.
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Affiliation(s)
- Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Sebastian Timmler
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Alonso Barrantes-Freer
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Mikael Simons
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
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11
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Gröger V, Cynis H. Human Endogenous Retroviruses and Their Putative Role in the Development of Autoimmune Disorders Such as Multiple Sclerosis. Front Microbiol 2018; 9:265. [PMID: 29515547 PMCID: PMC5826199 DOI: 10.3389/fmicb.2018.00265] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/05/2018] [Indexed: 12/13/2022] Open
Abstract
Human endogenous retroviruses (HERVs) are remnants of retroviral germ line infections of human ancestors and make up ~8% of the human genome. Under physiological conditions, these elements are frequently inactive or non-functional due to deactivating mutations and epigenetic control. However, they can be reactivated under certain pathological conditions and produce viral transcripts and proteins. Several disorders, like multiple sclerosis or amyotrophic lateral sclerosis are associated with increased HERV expression. Although their detailed contribution to individual diseases has yet to be elucidated, an increasing number of studies in vitro and in vivo suggest HERVs as potent modulators of the immune system. They are able to affect the transcription of other immune-related genes, interact with pattern recognition receptors, and influence the positive and negative selection of developing thymocytes. Interestingly, HERV envelope proteins can both stimulate and suppress immune responses based on different mechanisms. In the light of HERV proteins becoming an emerging drug target for autoimmune-related disorders and cancer, we will provide an overview on recent findings of the complex interactions between HERVs and the human immune system with a focus on autoimmunity.
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Affiliation(s)
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle, Germany
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12
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Gupta A, Al-Dasuqi K, Xia F, Askin G, Zhao Y, Delgado D, Wang Y. The Use of Noncontrast Quantitative MRI to Detect Gadolinium-Enhancing Multiple Sclerosis Brain Lesions: A Systematic Review and Meta-Analysis. AJNR Am J Neuroradiol 2017; 38:1317-1322. [PMID: 28522663 DOI: 10.3174/ajnr.a5209] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/22/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND Concerns have arisen about the long-term health effects of repeat gadolinium injections in patients with multiple sclerosis and the incomplete characterization of MS lesion pathophysiology that results from relying on enhancement characteristics alone. PURPOSE Our aim was to perform a systematic review and meta-analysis analyzing whether noncontrast MR imaging biomarkers can distinguish enhancing and nonenhancing brain MS lesions. DATA SOURCES Our sources were Ovid MEDLINE, Ovid Embase, and the Cochrane data base from inception to August 2016. STUDY SELECTION We included 37 journal articles on 985 patients with MS who had MR imaging in which T1-weighted postcontrast sequences were compared with noncontrast sequences obtained during the same MR imaging examination by using ROI analysis of individual MS lesions. DATA ANALYSIS We performed random-effects meta-analyses comparing the standard mean difference of each MR imaging metric taken from enhancing-versus-nonenhancing lesions. DATA SYNTHESIS DTI-based fractional anisotropy values are significantly different between enhancing and nonenhancing lesions (P = .02), with enhancing lesions showing decreased fractional anisotropy compared with nonenhancing lesions. Of the other most frequently studied MR imaging biomarkers (mean diffusivity, magnetization transfer ratio, or ADC), none were significantly different (P values of 0.30, 0.47, and 0.19. respectively) between enhancing and nonenhancing lesions. Of the limited studies providing diagnostic accuracy measures, gradient-echo-based quantitative susceptibility mapping had the best performance in discriminating enhancing and nonenhancing MS lesions. LIMITATIONS MR imaging techniques and patient characteristics were variable across studies. Most studies did not provide diagnostic accuracy measures. All imaging metrics were not studied in all 37 studies. CONCLUSIONS Noncontrast MR imaging techniques, such as DTI-based FA, can assess MS lesion acuity without gadolinium.
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Affiliation(s)
- A Gupta
- From the Department of Radiology (A.G., K.A.-D., F.X., Y.W.) .,Clinical and Translational Neuroscience Unit (A.G.), Feil Family Brain and Mind Research Institute
| | - K Al-Dasuqi
- From the Department of Radiology (A.G., K.A.-D., F.X., Y.W.)
| | - F Xia
- From the Department of Radiology (A.G., K.A.-D., F.X., Y.W.).,Department of Biomedical Engineering (F.X., Y.W.), Cornell University, Ithaca, New York
| | - G Askin
- Department of Healthcare Policy and Research (G.A., Y.Z.)
| | - Y Zhao
- Department of Healthcare Policy and Research (G.A., Y.Z.)
| | - D Delgado
- Samuel J. Wood Library and C.V. Starr Biomedical Information Center (D.D.), Weill Cornell Medicine, New York, New York
| | - Y Wang
- From the Department of Radiology (A.G., K.A.-D., F.X., Y.W.).,Department of Biomedical Engineering (F.X., Y.W.), Cornell University, Ithaca, New York
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13
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14
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Keller CW, Lünemann JD. Autophagy and Autophagy-Related Proteins in CNS Autoimmunity. Front Immunol 2017; 8:165. [PMID: 28289410 PMCID: PMC5326760 DOI: 10.3389/fimmu.2017.00165] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 02/02/2017] [Indexed: 12/13/2022] Open
Abstract
Autophagy comprises a heterogeneous group of cellular pathways that enables eukaryotic cells to deliver cytoplasmic constituents for lysosomal degradation, to recycle nutrients, and to survive during starvation. In addition to these primordial functions, autophagy has emerged as a key mechanism in orchestrating innate and adaptive immune responses and to shape CD4+ T cell immunity through delivery of peptides to major histocompatibility complex (MHC) class II-containing compartments (MIICs). Individual autophagy proteins additionally modulate expression of MHC class I molecules for CD8+ T cell activation. The emergence and expansion of autoreactive CD4+ and CD8+ T cells are considered to play a key role in the pathogenesis of multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis. Expression of the essential autophagy-related protein 5 (Atg5), which supports T lymphocyte survival and proliferation, is increased in T cells isolated from blood or brain tissues from patients with relapsing-remitting MS. Whether Atgs contribute to the activation of autoreactive T cells through autophagy-mediated antigen presentation is incompletely understood. Here, we discuss the complex functions of autophagy proteins and pathways in regulating T cell immunity and its potential role in the development and progression of MS.
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Affiliation(s)
- Christian W Keller
- Institute of Experimental Immunology, Laboratory of Neuroinflammation, University of Zürich , Zürich , Switzerland
| | - Jan D Lünemann
- Institute of Experimental Immunology, Laboratory of Neuroinflammation, University of Zürich, Zürich, Switzerland; Department of Neurology, University Hospital Zürich, Zürich, Switzerland
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15
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B7-H1 shapes T-cell-mediated brain endothelial cell dysfunction and regional encephalitogenicity in spontaneous CNS autoimmunity. Proc Natl Acad Sci U S A 2016; 113:E6182-E6191. [PMID: 27671636 DOI: 10.1073/pnas.1601350113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Molecular mechanisms that determine lesion localization or phenotype variation in multiple sclerosis are mostly unidentified. Although transmigration of activated encephalitogenic T cells across the blood-brain barrier (BBB) is a crucial step in the disease pathogenesis of CNS autoimmunity, the consequences on brain endothelial barrier integrity upon interaction with such T cells and subsequent lesion formation and distribution are largely unknown. We made use of a transgenic spontaneous mouse model of CNS autoimmunity characterized by inflammatory demyelinating lesions confined to optic nerves and spinal cord (OSE mice). Genetic ablation of a single immune-regulatory molecule in this model [i.e., B7-homolog 1 (B7-H1, PD-L1)] not only significantly increased incidence of spontaneous CNS autoimmunity and aggravated disease course, especially in the later stages of disease, but also importantly resulted in encephalitogenic T-cell infiltration and lesion formation in normally unaffected brain regions, such as the cerebrum and cerebellum. Interestingly, B7-H1 ablation on myelin oligodendrocyte glycoprotein-specific CD4+ T cells, but not on antigen-presenting cells, amplified T-cell effector functions, such as IFN-γ and granzyme B production. Therefore, these T cells were rendered more capable of eliciting cell contact-dependent brain endothelial cell dysfunction and increased barrier permeability in an in vitro model of the BBB. Our findings suggest that a single immune-regulatory molecule on T cells can be ultimately responsible for localized BBB breakdown, and thus substantial changes in lesion topography in the context of CNS autoimmunity.
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16
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Traboulsee A, Dehmeshki J, Peters KR, Griffin CM, Brex PA, Silver N, Ciccarrelli O, Chard DT, Barker GJ, Thompson AJ, Miller DH. Disability in multiple sclerosis is related to normal appearing brain tissue MTR histogram abnormalities. Mult Scler 2016; 9:566-73. [PMID: 14664468 DOI: 10.1191/1352458503ms958oa] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Background: Magnetization transfer ratio (MTR) histogram analysis provides a global measure of disease burden in multiple sclerosis (MS). MTR abnormalities in normal appearing brain tissue (NABT) provide quantitative information on the extent of tissue damage undetected by conventional T2-weighted (T2W) magnetic resonance imaging (MRI). A ims: 1) To compare the MTR histograms from NABT across a broad spectrum of relapse onset MS patients, including relapsing-remitting (RR) MS (including newly diagnosed and benign subgroups) and secondary progressive (SP) MS. 2) To determine the relationship between clinical disability and NA BT MTR histograms. Methods: 2D spin echo magnetization transfer imaging was performed on 70 RRMS and 25 SPMS patients and compared with 63 controls. MTR histograms were acquired for NA BT after extracting lesions and cerebrospinal fluid (C SF). T2W images were used to measure the brain parenchymal fraction (BPF) and T2 lesion load. Results: MS patients had a disease duration ranging from 0.5 to 37 years and an Expanded Disability Status Scale (EDSS) score ranging from 0 to 8.5. There was a significant decrease in NA BT mean MTR (± standard deviation) compared with controls (33.07 pu± 1.06 versus 34.26 pu± 0.47; P < 0.001) with an effect size of 2.56. The reductio n in NA BT mean MTR varied among patient groups from 4.9% for SPMS, 3% for all RRMS, 2.7% for early RRMS and 2.5% for benign MS, compared with controls. NA BT mean MTR correlated significantly with T2 lesion load (r = -0.82) and BPF (r =0.58). EDSS score correlated with NA BT mean MTR (r = -0.43), BPF (r = -0.33) and with T2 lesion load (r =0.59). Multivariate analysis using NA BT MTR peak height, T2 lesion load and BPF combined only accounted for 38% of the variance in the EDSS (r =0.62; P <0.001). Disease duration accounted for an additional 14% of variance in the EDSS (r =0.72; P <0.001). Conclusions: There is evidence of diffuse abnormalities in NA BT in addition to global brain atrophy in relapse onset MS patients, including those with recently diagnosed RRMS and benign MS. The abnormalities are greatest in patients with the more disabling SPMS. A trophy, NA BT and lesion abnormalities are all partly correlated; the processes marked by these MR measures all contribute to disability in MS, providing complementary information relevant to the complex pathological processes that occur in MS.
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Affiliation(s)
- A Traboulsee
- NMR Research Unit, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
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Enzinger C, Barkhof F, Ciccarelli O, Filippi M, Kappos L, Rocca MA, Ropele S, Rovira À, Schneider T, de Stefano N, Vrenken H, Wheeler-Kingshott C, Wuerfel J, Fazekas F. Nonconventional MRI and microstructural cerebral changes in multiple sclerosis. Nat Rev Neurol 2015; 11:676-86. [PMID: 26526531 DOI: 10.1038/nrneurol.2015.194] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
MRI has become the most important paraclinical tool for diagnosing and monitoring patients with multiple sclerosis (MS). However, conventional MRI sequences are largely nonspecific in the pathology they reveal, and only provide a limited view of the complex morphological changes associated with MS. Nonconventional MRI techniques, such as magnetization transfer imaging (MTI), diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) promise to complement existing techniques by revealing more-specific information on microstructural tissue changes. Past years have witnessed dramatic advances in the acquisition and analysis of such imaging data, and numerous studies have used these tools to probe tissue alterations associated with MS. Other MRI-based techniques-such as myelin-water imaging, (23)Na imaging, magnetic resonance elastography and magnetic resonance perfusion imaging-might also shed new light on disease-associated changes. This Review summarizes the rapid technical progress in the use of MRI in patients with MS, with a focus on nonconventional structural MRI. We critically discuss the present utility of nonconventional MRI in MS, and provide an outlook on future applications, including clinical practice. This information should allow appropriate selection of advanced MRI techniques, and facilitate their use in future studies of this disease.
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Affiliation(s)
- Christian Enzinger
- Division of Neuroradiology, Medical University of Graz, Auenbruggerplatz 22, 8036 Graz, Austria.,Department of Neurology, Medical University of Graz, Auenbruggerplatz 22, 8036 Graz, Austria
| | - Frederik Barkhof
- VU University MS Center Amsterdam, Department of Radiology and Nuclear Medicine and Department of Physics &Medical Technology, VU University Medical Center, Netherlands
| | - Olga Ciccarelli
- NMR Research Unit, Queen Square MS Centre, University College London Institute of Neurology, UK
| | - Massimo Filippi
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Italy
| | - Ludwig Kappos
- Department of Neurology, University of Basel, Switzerland
| | - Maria A Rocca
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Italy
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Auenbruggerplatz 22, 8036 Graz, Austria
| | - Àlex Rovira
- Magnetic Resonance Unit, Cemcat, Hospital Vall d'Hebron, Autonomous University of Barcelona, Spain
| | - Torben Schneider
- NMR Research Unit, Queen Square MS Centre, University College London Institute of Neurology, UK
| | - Nicola de Stefano
- Department of Neurological and Behavioural Sciences, University of Siena, Italy
| | - Hugo Vrenken
- VU University MS Center Amsterdam, Department of Radiology and Nuclear Medicine and Department of Physics &Medical Technology, VU University Medical Center, Netherlands
| | | | - Jens Wuerfel
- Medical Image Analysis Center, University Hospital Basel, Switzerland
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Auenbruggerplatz 22, 8036 Graz, Austria
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18
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Enzinger C, Fazekas F. Measuring Gray Matter and White Matter Damage in MS: Why This is Not Enough. Front Neurol 2015; 6:56. [PMID: 25852635 PMCID: PMC4362212 DOI: 10.3389/fneur.2015.00056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/27/2015] [Indexed: 01/06/2023] Open
Affiliation(s)
- Christian Enzinger
- Department of Neurology, Medical University of Graz , Graz , Austria ; Division of Neuroradiology, Department of Radiology, Medical University of Graz , Graz , Austria
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz , Graz , Austria
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19
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Garcia M, Gloor M, Bieri O, Radue EW, Lieb JM, Cordier D, Stippich C. Imaging of Primary Brain Tumors and Metastases with Fast Quantitative 3-Dimensional Magnetization Transfer. J Neuroimaging 2015; 25:1007-14. [PMID: 25702714 DOI: 10.1111/jon.12222] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 12/04/2014] [Accepted: 12/10/2014] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE This study assesses whether magnetization transfer (MT) imaging provides additive information to conventional MRI in brain tumors. METHODS MT data of 26 patients with neoplastic and metastatic brain tumors were analyzed at 1.5 T. For the 3 largest tumor groups investigated in this study--glioblastoma multiforme (GBM), meningiomas, and metastases-statistical comparisons were performed. Analyzed MT parameters included the magnetization transfer ratio (MTR) and 4 quantitative MT parameters (qMT): Relaxation times (T1, T2), exchange rate (kf), and macromolecular content (F). Total imaging time of high-resolution whole brain MTR and qMT imaging with balanced steady-state free precession required 9 minutes. Five ROIs were chosen: Contrast-enhancing (T1W-CE), noncontrast-enhancing (T1W-non-CE), proximal hyperintensity (T2W-pSI), distal hyperintensity (T2W-dSI), and a reference (ref). RESULTS Pathologies showed significant (P < .05) MT changes (MTR and qMT) compared to the reference. The T1W-CE, T1W-non-CE, and T2W-pSI ROIs of GBMs, meningiomas, and metastases showed significant differences in MTR and qMT estimates. Similar MTR with significant different qMT values were observed in several ROIs among different lesions. MT maps (MTR and qMT) indicated changes in tissue appearing unaffected on MRI in most glial tumors. CONCLUSIONS MTR and qMT imaging enables a better differentiation between brain tumors and provides additive information to MRI.
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Affiliation(s)
- Meritxell Garcia
- Division of Diagnostic & Interventional Neuroradiology, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Monika Gloor
- Division of Radiological Physics, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Oliver Bieri
- Division of Radiological Physics, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Ernst-Wilhelm Radue
- Medical Imaging Analysis Center, University of Basel Hospital, Basel, Switzerland
| | - Johanna M Lieb
- Division of Diagnostic & Interventional Neuroradiology, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Dominik Cordier
- Department of Neurosurgery, University of Basel Hospital, Basel, Switzerland
| | - Christoph Stippich
- Division of Diagnostic & Interventional Neuroradiology, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
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Alvarez JI, Saint-Laurent O, Godschalk A, Terouz S, Briels C, Larouche S, Bourbonnière L, Larochelle C, Prat A. Focal disturbances in the blood-brain barrier are associated with formation of neuroinflammatory lesions. Neurobiol Dis 2014; 74:14-24. [PMID: 25448765 DOI: 10.1016/j.nbd.2014.09.016] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/24/2014] [Indexed: 12/15/2022] Open
Abstract
Early changes in the normal appearing white matter of multiple sclerosis (MS) patients precede the appearance of gadolinium-enhancing lesions. Although these findings suggest blood-brain barrier (BBB) breakdown as an important feature in MS pathogenesis, limited information is available on the BBB alterations during lesion genesis. Here, we perform a longitudinal characterization of the vascular, neuropathological and immunological changes before lesion formation in mice developing spontaneous relapsing-remitting experimental autoimmune encephalomyelitis (sRR-EAE). We found a significant upregulation of Th1 and Th17 cytokines in the periphery of sRR-EAE mice before any evident neuropathology. In the CNS, BBB and astroglial activations were the first pathological changes occurring after 45days of age and were followed by immune cell infiltration by day 50. These pathological alterations subsequently led to perivascular demyelination and disease onset. In MS, (p)reactive lesions mirrored the changes seen in early sRR-EAE by displaying considerable BBB disruption, perivascular astrogliosis, redistribution of junctional proteins and increased expression of endothelial cell adhesion molecules. Our findings suggest that BBB breach occurs before significant immune cell infiltration and demyelination. In addition, peripheral immune activation during sRR-EAE precedes CNS pathology, suggesting that outside in signaling mechanisms play a role in the development of neuroinflammatory lesions.
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Affiliation(s)
- Jorge Ivan Alvarez
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada.
| | - Olivia Saint-Laurent
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Alisha Godschalk
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Simone Terouz
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Casper Briels
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Sandra Larouche
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Lyne Bourbonnière
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Catherine Larochelle
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Alexandre Prat
- Neuroimmunology Unit, Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
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Willis MD, Harding KE, Wardle M, Pickersgill TP, Tomassini V, Loveless S, Robertson NP. Site-specific clinical disease onset in multiple sclerosis. Eur J Neurol 2014; 22:732-5. [PMID: 25196326 DOI: 10.1111/ene.12564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/25/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE Multiple sclerosis is a chronic inflammatory disorder of the central nervous system characterized by acute episodes of neurological dysfunction thought to reflect focal areas of demyelination occurring in clinically eloquent areas. These symptomatic relapses are generally considered to be random clinical events occurring without discernible pattern. The hypothesis that relapses may follow a predetermined sequence and may provide insights into underlying pathological processes was investigated. METHODS Employing prospective clinical database data from 1482 patients who had experienced one or more consecutive relapses were analysed. Using regression analysis, site and symptom of index event were compared with those of first relapse. RESULTS It is demonstrated that following disease ignition subsequent relapses may not be random events but dependent on characteristics of the index event. All anatomical sites were more likely to be affected in the first relapse if that site had been involved in the index event with a similar association observed when comparing by symptoms. CONCLUSION These findings have importance in understanding the evolution of the disease and predicting individual disease progression and may aid with patient counselling and management.
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Affiliation(s)
- M D Willis
- Institute of Psychological Medicine and Clinical Neuroscience, Cardiff University, University Hospital of Wales, Heath Park, Cardiff, UK
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22
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Maggi P, Macri SMC, Gaitán MI, Leibovitch E, Wholer JE, Knight HL, Ellis M, Wu T, Silva AC, Massacesi L, Jacobson S, Westmoreland S, Reich DS. The formation of inflammatory demyelinated lesions in cerebral white matter. Ann Neurol 2014; 76:594-608. [PMID: 25088017 DOI: 10.1002/ana.24242] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/31/2014] [Accepted: 07/31/2014] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Vascular permeability and inflammatory demyelination are intimately linked in the brain, but what is their temporal relationship? We aimed to determine the radiological correlates of the earliest tissue changes accompanying demyelination in a primate model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE) in the common marmoset. METHODS By 7T magnetic resonance imaging (MRI), T1 maps, proton density, and T2-weighted images were acquired before and after EAE induction in 5 marmosets (every other week before lesions appeared, weekly thereafter). From scans before and after intravenous injection of contrast material, we measured the evolution of lesional blood-brain barrier (BBB) permeability, comparing in vivo MRI to postmortem tissue examination. RESULTS On average, BBB permeability increased 3.5-fold (p < 0.0001) over the 4 weeks prior to lesion appearance. Permeability gradually decreased after lesion appearance, with attendant changes in the distribution of inflammatory cells (predominantly macrophages and microglia) and demyelination. On tissue analysis, we also identified small perivascular foci of microglia and T cells without blood-derived macrophages or demyelination. These foci had no visible MRI correlates, although permeability within the foci, but not outside, increased in the weeks before the animals died (p < 0.0001). INTERPRETATION This study provides compelling evidence that in marmoset EAE, which forms lesions strongly resembling those of MS, early changes in vascular permeability are associated with perivascular inflammatory cuffing and parenchymal microglial activation but precede the arrival of blood-derived monocytes that accompany demyelination. Prospective detection of transient permeability changes could afford an opportunity for early intervention to forestall tissue damage in newly forming lesions.
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Affiliation(s)
- Pietro Maggi
- National Institute for Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA; Department of Neurosciences, Drug Research, and Child's Health, University of Florence, Florence, Italy
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Alomair OI, Smith MT, Brereton IM, Galloway GJ, Kurniawan ND. Current developments in MRI for assessing rodent models of multiple sclerosis. FUTURE NEUROLOGY 2014. [DOI: 10.2217/fnl.14.33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT: MRI is a key radiological imaging technique that plays an important role in the diagnosis and characterization of heterogeneous multiple sclerosis (MS) lesions. Various MRI methodologies such as conventional T 1/T 2 contrast, contrast agent enhancement, diffusion-weighted imaging, magnetization transfer imaging and susceptibility weighted imaging have been developed to determine the severity of MS pathology, including demyelination/remyelination and brain connectivity impairment from axonal loss. The broad spectrum of MS pathology manifests in diverse patient MRI presentations and affects the accuracy of patient diagnosis. To study specific pathological aspects of the disease, rodent models such as experimental autoimmune encephalomyelitis, virus-induced and toxin-induced demyelination have been developed. This review aims to present key developments in MRI methodology for better characterization of rodent models of MS.
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Affiliation(s)
- Othman I Alomair
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia
- College of Applied Medical Science, King Saud University, Riyadh, Saudi Arabia
| | - Maree T Smith
- School of Pharmacy, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Integrated Preclinical Drug Development, The University of Queensland, Brisbane, Queensland, Australia
| | - Ian M Brereton
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia
| | - Graham J Galloway
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia
| | - Nyoman D Kurniawan
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia
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Ontaneda D, Sakaie K, Lin J, Wang X, Lowe MJ, Phillips MD, Fox RJ. Identifying the start of multiple sclerosis injury: a serial DTI study. J Neuroimaging 2014; 24:569-576. [PMID: 25370339 DOI: 10.1111/jon.12082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 10/14/2013] [Accepted: 11/22/2013] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The events leading up to the development of new multiple sclerosis (MS) lesions on conventional imaging are unknown. The purpose of this study is to use diffusion tensor imaging (DTI) to investigate prelesional changes in MS to better understand the pathological changes that lead to lesion development. METHODS Twenty-one patients with relapsing MS starting natalizumab therapy underwent serial DTI for 12-18 months. Regions of interest were outlined within normal-appearing white matter and new gadolinium-enhancing lesions that developed over the course of the study. Images from all time points were coregistered and nonparametric regression was used to assess DTI changes prior to lesion appearance. RESULTS A total of 31 newly enhancing lesions were identified. Significant changes in transverse diffusivity (TD) (P < .001), longitudinal diffusivity (LD) (P = .025), mean diffusivity (MD) (P < .001), and fractional anisotropy (FA) (P = .04) were observed prior to gadolinium enhancement. A progressive increase in TD and LD occurred up to 10 months prior to lesion development. DTI measures in normal appearing white matter remained unchanged over the study period. CONCLUSIONS A significant change in diffusion measures can be seen prior to gadolinium enhancement. Changes in TD drove changes in FA and MD, providing evidence for impaired myelin integrity prior to gadolinium enhancement. DTI may be a sensitive measure for early detection of inflammatory disease activity in MS.
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Affiliation(s)
- Daniel Ontaneda
- Mellen Center, Department of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, OH
| | - Ken Sakaie
- Imaging Institute, Cleveland Clinic, Cleveland, OH
| | - Jian Lin
- Imaging Institute, Cleveland Clinic, Cleveland, OH
| | - Xiaofeng Wang
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH
| | - Mark J Lowe
- Imaging Institute, Cleveland Clinic, Cleveland, OH
| | | | - Robert J Fox
- Mellen Center, Department of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, OH
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25
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Filippi M, Charil A, Rovaris M, Absinta M, Rocca MA. Insights from magnetic resonance imaging. HANDBOOK OF CLINICAL NEUROLOGY 2014; 122:115-149. [PMID: 24507516 DOI: 10.1016/b978-0-444-52001-2.00006-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Recent years have witnessed impressive advancements in the use of magnetic resonance imaging (MRI) for the assessment of patients with multiple sclerosis (MS). Complementary to the clinical evaluation, conventional MRI (cMRI) provides crucial pieces of information for the diagnosis of MS, the understanding of its natural history, and monitoring the efficacy of experimental treatments. Measures derived from cMRI present clear advantages over the clinical assessment, including their more objective nature and an increased sensitivity to MS-related changes. However, the correlation between these measures and the clinical manifestations of the disease remains weak, and this can be explained, at least partially, by the limited ability of cMRI to characterize and quantify the heterogeneous features of MS pathology. Quantitative MR-based techniques have the potential to overcome the limitations of cMRI. Magnetization transfer MRI, diffusion-weighted and diffusion tensor MRI with fiber tractography, proton magnetic resonance spectroscopy, T1 and T2 relaxation time measurement, and functional MRI are contributing to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. All conventional and nonconventional MR techniques will benefit from the use of high-field MR systems (3.0T or more).
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
| | - Arnaud Charil
- Neuroimaging Research Unit, Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Marco Rovaris
- Neuroimaging Research Unit, Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Martina Absinta
- Neuroimaging Research Unit, Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Maria Assunta Rocca
- Neuroimaging Research Unit, Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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26
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Rovira A, Auger C, Alonso J. Magnetic resonance monitoring of lesion evolution in multiple sclerosis. Ther Adv Neurol Disord 2013; 6:298-310. [PMID: 23997815 DOI: 10.1177/1756285613484079] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Disease activity in multiple sclerosis (MS) is strongly linked to the formation of new lesions, which involves a complex sequence of inflammatory, degenerative, and reparative processes. Conventional magnetic resonance imaging (MRI) techniques, such as T2-weighted and gadolinium-enhanced T1-weighted sequences, are highly sensitive in demonstrating the spatial and temporal dissemination of demyelinating plaques in the brain and spinal cord. Hence, these techniques can provide quantitative assessment of disease activity in patients with MS, and they are commonly used in monitoring treatment efficacy in clinical trials and in individual cases. However, the correlation between conventional MRI measures of disease activity and the clinical manifestations of the disease, particularly irreversible disability, is weak. This has been explained by a process of exhaustion of both structural and functional redundancies that increasingly prevents repair and recovery, and by the fact that these imaging techniques do not suffice to explain the entire spectrum of the disease process and lesion development. Nonconventional MRI techniques, such as magnetization transfer imaging, diffusion-weighted imaging, and proton magnetic resonance spectroscopy, which can selectively measure the more destructive aspects of MS pathology and monitor the reparative mechanisms of this disease, are increasingly being used for serial analysis of new lesion formation and provide a better approximation of the pathological substrate of MS plaques. These nonconventional MRI-based measures better assess the serial changes in newly forming lesions and improve our understanding of the relationship between the damaging and reparative mechanisms that occur in MS.
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Affiliation(s)
- Alex Rovira
- Magnetic Resonance Unit (IDI), Department of Radiology, Hospital Universitari Vall d'Hebron, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
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27
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Verhey LH, Sled JG. Advanced magnetic resonance imaging in pediatric multiple sclerosis. Neuroimaging Clin N Am 2013; 23:337-54. [PMID: 23608694 DOI: 10.1016/j.nic.2012.12.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This review summarizes results from studies that have applied advanced magnetic resonance (MR) imaging techniques to patients with pediatric-onset multiple sclerosis (MS), and includes a discussion of cortical imaging techniques, volumetry, magnetization transfer and diffusion tensor imaging, proton magnetic resonance spectroscopy, and functional MR imaging. Multicenter studies on the sensitivity of these techniques to natural history of disease and treatment response are required before their implementation into clinical practice.
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28
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Vigeveno RM, Wiebenga OT, Wattjes MP, Geurts JJG, Barkhof F. Shifting imaging targets in multiple sclerosis: from inflammation to neurodegeneration. J Magn Reson Imaging 2012; 36:1-19. [PMID: 22696123 DOI: 10.1002/jmri.23578] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Classically multiple sclerosis (MS) has been regarded as an auto-immune disease of the white matter in the central nervous system leading to severe disability over the course of several decades. Current therapeutic strategies in MS are mostly based on either immune suppression or immune modulation. Although effective in decreasing relapse frequency and severity as well as delaying disease progression, MS pathology ensues nonetheless. In the last decade it became evident that gray matter pathology plays an important role in disease progression and helps explaining certain aspects of MS-related disability such as cognitive decline. Conventional MRI outcome measures commonly used in clinical trials are sufficient to demonstrate an anti-inflammatory drug-effect but lack pathological specificity and are poor to moderate predictors of disability. In this article, we review new insights in gray matter pathology and functional reorganization in MS and how these novel fields in MS research may validate and establish new MRI outcome measures, aid in the development of new therapeutic strategies for neuroprotection and neurorepair, and may lead to development of novel predictive measures of disability and disease progression in MS.
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Affiliation(s)
- René M Vigeveno
- VU University Medical Center, Department of Radiology, Amsterdam, the Netherlands
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29
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Fast high-resolution brain imaging with balanced SSFP: Interpretation of quantitative magnetization transfer towards simple MTR. Neuroimage 2012; 59:202-11. [DOI: 10.1016/j.neuroimage.2011.07.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/12/2011] [Indexed: 11/17/2022] Open
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30
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Ropele S, Langkammer C, Enzinger C, Fuchs S, Fazekas F. Relaxation time mapping in multiple sclerosis. Expert Rev Neurother 2011; 11:441-50. [PMID: 21375449 DOI: 10.1586/ern.10.129] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Several relaxation mapping techniques have been proposed to quantitatively assess disease-related brain tissue changes in multiple sclerosis. Newer developments also account for the distribution of hydrogen protons in different tissue compartments, and therefore provide markers for myelin and macromolecular content. This article will cover the broad spectrum of the pulse sequences and analysis techniques related to this topic that are currently available. Various technical and practical limitations linked with specific approaches will be discussed. These include acquisition time, accuracy and precision, radiofrequency absorption and limited coverage of the brain. Finally, the application of these techniques in the context of multiple sclerosis will be reviewed.
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31
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Petzold A, Tozer DJ, Schmierer K. Axonal damage in the making: neurofilament phosphorylation, proton mobility and magnetisation transfer in multiple sclerosis normal appearing white matter. Exp Neurol 2011; 232:234-9. [PMID: 21958956 PMCID: PMC3277890 DOI: 10.1016/j.expneurol.2011.09.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 09/06/2011] [Accepted: 09/09/2011] [Indexed: 11/29/2022]
Abstract
Aims Multiple sclerosis (MS) leaves a signature on the phosphorylation and thus proton binding capacity of axonal neurofilament (Nf) proteins. The proton binding capacity in a tissue is the major determinant for exchange between bound and free protons and thus the magnetisation transfer ratio (MTR). This study investigated whether the MTR of non-lesional white matter (NLWM) was related to the brain tissue concentration of neurofilament phosphoforms. Methods Unfixed post-mortem brain slices of 12 MS patients were analysed using MTR, T1 at 1.5 T. Blocks containing NLWM were processed for embedding in paraffin and inspected microscopically. Adjacent tissue was microdissected, homogenised and specific protein levels were quantified by ELISA for the Nf heavy chain (NfH) phosphoforms, glial fibrillary acidic protein (GFAP), S100B and ferritin. Results Averaged hyperphosphorylated NfH (SMI34) but not phosphorylated NfH (SMI35) levels were different between individual patients NLWM. The concentration of hyperphosphorylated NfH-SMI34 correlated with T1 (R = 0.70, p = 0.0114) and — inversely — with MTR (R =−0.73, p = 0.0065). NfH-SMI35 was not correlated to any of the MR indices. Conclusions Post-translational modifications of axonal proteins such as phosphorylation of neurofilaments occur in NLWM and may precede demyelination. The resulting change of proton mobility influences MTR and T1. This permits the in vivo detection of these subtle tissue changes on a proteomic level in patients with MS.
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Affiliation(s)
- A Petzold
- UCL Institute of Neurology, Department of Neuroinflammation, Queen Square, London WC1N 3BG, UK.
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32
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Sahraian MA, Radue EW, Haller S, Kappos L. Black holes in multiple sclerosis: definition, evolution, and clinical correlations. Acta Neurol Scand 2010; 122:1-8. [PMID: 20003089 DOI: 10.1111/j.1600-0404.2009.01221.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetic resonance imaging (MRI) is a sensitive paraclinical test for diagnosis and assessment of disease progression in multiple sclerosis (MS) and is often used to evaluate therapeutic efficacy. The formation of new T2-hyperintense MRI lesions is commonly used to measure disease activity, but lacks specificity because edema, inflammation, gliosis, and axonal loss all contribute to T2 lesion formation. As the role of neurodegeneration in the pathophysiology of MS has become more prominent, the formation and evolution of chronic or persistent Tl-hypointense lesions (black holes) have been used as markers of axonal loss and neuronal destruction to measure disease activity. Despite the use of various detection methods, including advanced imaging techniques such as magnetization transfer imaging and magnetic resonance spectroscopy, correlation of persistent black holes with clinical outcomes in patients with MS remains uncertain. Furthermore, although axonal loss and neuronal tissue destruction are known to contribute to irreversible disability in patients with MS, there are limited data on the effect of therapy on longitudinal change in Tl-hypointense lesion volume. Measurement of black holes in clinical studies may elucidate the underlying pathophysiology of MS and may be an additional method of evaluating therapeutic efficacy.
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van den Elskamp IJ, Knol DL, Vrenken H, Karas G, Meijerman A, Filippi M, Kappos L, Fazekas F, Wagner K, Pohl C, Sandbrink R, Polman CH, Uitdehaag BMJ, Barkhof F. Lesional magnetization transfer ratio: a feasible outcome for remyelinating treatment trials in multiple sclerosis. Mult Scler 2010; 16:660-9. [PMID: 20350960 DOI: 10.1177/1352458510364630] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Magnetization transfer ratio (MTR) is a sensitive parameter to quantify the integrity of myelinated white matter in patients with multiple sclerosis. Lesional MTR decreases in the acute phase due to demyelination, and subsequently shows recovery depending on the degree of remyelination in the absence of axonal loss. Recovery of average lesion MTR therefore might prove a viable outcome measure to assess the effect of remyelinating agents. Our objective was to determine the required sample size for phase II multicentre clinical trials using the recovery of average lesion MTR as primary outcome measure. With 7-monthly MRI scans, the MTR evolution of 349 new enhancing lesions before and after enhancement was assessed in 32 MS patients from 5 centres. Multilevel models were fitted to the data yielding estimates for the variance components, which were applied in power calculations. Sample sizes were determined for placebo-controlled, multicentre trials using lesional MTR recovery post-enhancement as primary outcome measure. Average lesion MTR decreased slightly in the build-up to enhancement, decreased dramatically during enhancement and showed recovery in the period after cessation. The power calculations showed that for a power of 80%, approximately 136 patients per trial (mean number of 6 lesions per patient) are required to detect a 30% increase in lesional MTR post-enhancement compared with placebo, whereas 48 subjects are required to detect a 50% increase in lesional MTR compared with placebo. Recovery of lesion MTR is a feasible outcome measure for future multicentre clinical trials measuring the effect of remyelinating agents.
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Affiliation(s)
- I J van den Elskamp
- Department of Radiology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands.
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Tomassini V, Palace J. Multiple sclerosis lesions: insights from imaging techniques. Expert Rev Neurother 2009; 9:1341-59. [PMID: 19769449 DOI: 10.1586/ern.09.83] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hallmark of multiple sclerosis (MS) pathology is the presence of inflammatory demyelinated lesions distributed throughout the CNS. Along with more diffuse tissue abnormalities, it is considered one of the major determinants of neurological deficit in MS. Conventional MRI has contributed to improve our understanding of MS pathology and has provided objective and reliable measures to monitor the effect of treatments. Advanced MRI techniques have offered the opportunity to quantify pathological changes in lesions, as well as in normal-appearing brain tissue and to characterize their dynamics. This review will discuss the characteristics and development of MS lesions and the contribution of conventional and quantitative MRI techniques to understanding pathological changes associated with them.
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Affiliation(s)
- Valentina Tomassini
- Oxford Centre for Functional MRI of the Brain (FMRIB), The University of Oxford, Department of Clinical Neurology, John Radcliffe Hospital, Headley Way, Headigton, Oxford OX39DU, UK.
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Strasser-Fuchs S, Enzinger C, Ropele S, Wallner M, Fazekas F. Clinically benign multiple sclerosis despite large T2 lesion load: can we explain this paradox? Mult Scler 2007; 14:205-11. [PMID: 17986507 DOI: 10.1177/1352458507082354] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Magnetic resonance imaging (MRI) techniques such as magnetization transfer imaging and magnetic resonance spectroscopy (MRS) may reveal otherwise undetectable tissue damage in multiple sclerosis (MS) and can serve to explain more severe disability than expected from conventional MRI. That an inverse situation may exist where non-conventional quantitative MRI and MRS metrics would indicate less abnormality than expected from T2 lesion load to explain preserved clinical functioning was hypothesized. Quantitative MRI and MRS were obtained in 13 consecutive patients with clinically benign MS (BMS; mean age 44 +/- 9 years) despite large T 2 lesion load and in 15 patients with secondary progressive MS (SPMS; mean age 47 +/- 6 years) matched for disease duration. The magnetization transfer ratio (MTR), magnetization transfer rate (kfor), brain parenchymal fraction (BPF) and brain metabolite concentrations from proton MRS were determined. BMS patients were significantly less disabled than their SPMS counterparts (mean expanded disability status score: 2.1 +/- 1.1 versus 6.2 +/- 1.1; P < 0.001) and had an even somewhat higher mean T2 lesion load (41.2 +/- 27.1 versus 27.9 +/- 24.8 cm3; P = 0.19). Normal appearing brain tissue histogram metrics for MTR and kfor, mean MTR and kfor of MS lesions and mean BPF were similar in BMS and SPMS patients. Levels of N-acetyl-aspartate, choline and myoinositol were comparable between groups. This study thus failed to explain the preservation of function in our BMS patients with large T2 lesion load by a higher morphologic or metabolic integrity of the brain parenchyma. Functional compensation must come from other mechanisms such as brain plasticity.
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Affiliation(s)
- S Strasser-Fuchs
- Department of Neurology, Division of Neuroradiology, Medical University, Graz, Austria
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36
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Laule C, Vavasour IM, Kolind SH, Li DKB, Traboulsee TL, Moore GRW, MacKay AL. Magnetic resonance imaging of myelin. Neurotherapeutics 2007; 4:460-84. [PMID: 17599712 PMCID: PMC7479725 DOI: 10.1016/j.nurt.2007.05.004] [Citation(s) in RCA: 230] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The ability to measure myelin in vivo has great consequences for furthering our knowledge of normal development, as well as for understanding a wide range of neurological disorders. The following review summarizes the current state of myelin imaging using MR. We consider five MR techniques that have been used to study myelin: 1) conventional MR, 2) MR spectroscopy, 3) diffusion, 4) magnetization transfer, and 5) T2 relaxation. Fundamental studies involving peripheral nerve and MR/histology comparisons have aided in the interpretation and validation of MR data. We highlight a number of important findings related to myelin development, damage, and repair, and we conclude with a critical summary of the current techniques available and their potential to image myelin in vivo.
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Affiliation(s)
- Cornelia Laule
- Department of Radiology, University of British Columbia, Vancouver, BC, V6T 2B5 Canada.
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Filippi M, Rocca MA. Magnetization transfer magnetic resonance imaging of the brain, spinal cord, and optic nerve. Neurotherapeutics 2007; 4:401-13. [PMID: 17599705 PMCID: PMC7479733 DOI: 10.1016/j.nurt.2007.03.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnetic resonance imaging is highly sensitive in revealing CNS abnormalities associated with several neurological conditions, but lacks specificity for their pathological substrates. In addition, MRI does not allow evaluation of the presence and extent of damage in regions that appear normal on conventional MRI sequences and that postmortem studies have shown to be affected by pathology. Quantitative MR-based techniques with increased pathological specificity to the heterogeneous substrates of CNS pathology have the potential to overcome such limitations. Among these techniques, one of the most extensively used for the assessment of CNS disorders is magnetization transfer MRI (MT-MRI). The application of this technique for the assessment of damage in macroscopic lesions, in normal-appearing white and gray matter, and in the spinal cord and optic nerve of patients with several neurological conditions is providing important in vivo information-dramatically improving our understanding of the factors associated with the appearance of clinical symptoms and the accumulation of irreversible disability. MT-MRI also has the potential to contribute to the diagnostic evaluation of several neurological conditions and to improve our ability to monitor treatment efficacy in experimental trials.
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Department of Neurology, Scientific Institute and University Hospital San Raffaele, Milan, Italy.
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Abstract
In multiple sclerosis (MS), conventional magnetic resonance imaging (cMRI) has proved to be sensitive for detecting lesions and their changes over time. However, cMRI is not able to characterize and quantify the tissue damage within and outside such lesions. Magnetization transfer (MT) MRI is a quantitative technique with the potential to overcome this limitation and, as a consequence, to provide additional information about the nature and the extent of tissue damage associated to this disease. During the last 10 years, MT MRI indeed has allowed us to quantify the structural changes occurring within and outside lesions visible on cMRI scans, thus providing a more accurate in vivo picture of the heterogeneity of MS and, as a consequence, improving our ability to monitor the evolution of the disease. The application of MT MRI to the study of MS has contributed to change our understanding of how MS causes irreversible disability by showing that MS is more than an inflammatory-demyelinating condition of the white matter of the central nervous system.
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
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Vrenken H, Geurts JJG. Gray and normal-appearing white matter in multiple sclerosis: an MRI perspective. Expert Rev Neurother 2007; 7:271-9. [PMID: 17341175 DOI: 10.1586/14737175.7.3.271] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Besides focal white matter lesions, multiple sclerosis brain tissue also displays abnormalities in the gray matter and the normal-appearing white matter. Recent advances in magnetic resonance imaging studies of both types of tissue are discussed. Herein, normal-appearing white matter abnormalities are being found in quantitative magnetic resonance investigations, consistent with a limited degree of axonal damage and/or demyelination, and an increase of glial cells, but the specific nature of the histopathological changes underlying the quantitative magnetic resonance abnormalities remains unclear. Gray matter studies have demonstrated that much of the disease process remains undetected by conventional magnetic resonance imaging. Although newly developed techniques, such as 3D double-inversion recovery, may greatly improve detection of cortical pathology, it remains important to investigate the resultant effects on the cortical tissue alongside this, by studying integrity of normal-appearing cortical tissue through quantitative magnetic resonance studies, as well as the net neurodegenerative effect through measurements of cortical thickness and cortical atrophy (rates). To improve our understanding of normal-appearing white and gray matter changes, their mutual relations, and their relations to clinical changes, further in vivo magnetic resonance imaging studies are required. Specifically, it is proposed that more spatially specific investigations, ideally utilizing subject-specific anatomical information from, for example, diffusion fiber-tracking techniques, could be used to gain more insight into the relations between normal-appearing white matter changes, cortical changes, magnetic resonance visible focal-lesions, and physical and cognitive deficits.
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Affiliation(s)
- Hugo Vrenken
- MS Center Amsterdam, VU University Medical Center, Department of Physics & Medical Technology, De Boelelaan, Amsterdam, The Netherlands.
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Abstract
Magnetization transfer (MT) is a relatively new way of generating contrast in magnetic resonance (MR) images that is sensitive to the density of the macromolecules found throughout tissue structures such as membranes, myelin, and organelles. MT imaging (MTI) can provide a quantitative measure of macromolecular density, and therefore of tissue damage, and has been applied in the central nervous system in multiple sclerosis (MS) and other diseases. This article introduces the contrast mechanisms behind MTI and gives some practical guidance about implementing MTI and about quantitative analysis of the MT scans. An overview of MT measurements made in animal studies, in postmortem tissue samples, and in other demyelinating diseases attempts to rationalize the pathological basis of changes in MT contrast in MS. The application of MTI to MS is reviewed, with emphasis on the contribution that MTI has made to the current understanding of the MS disease process, both its natural history and the response to treatment. The pathological basis of abnormal MT contrast is still open to debate, with many conflicting reports; indeed, it is unlikely that a simple measure of MT effect will reveal the details of pathology that is a combination of inflammation, demyelination, remyelination, and axonal loss. There is no doubt, however, that MT measurements have contributed to the current understanding of both disease progression and the response to treatment and will prove to be a valuable tool in the future, particularly if more refined techniques can be applied practically in multicenter studies.
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Affiliation(s)
- Mark A Horsfield
- Department of Cardiology, University of Leicester, Leicester Royal Infirmary, Leicester LE1 5WW, UK.
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Sjöbeck M, Haglund M, Englund E. Decreasing myelin density reflected increasing white matter pathology in Alzheimer's disease--a neuropathological study. Int J Geriatr Psychiatry 2005; 20:919-26. [PMID: 16163742 DOI: 10.1002/gps.1384] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND White matter disease (WMD) is frequently seen in Alzheimer's disease (AD) at neuropathological examination. It is defined as a subtotal tissue loss with a reduction of myelin, axons and oligodendrocytes as well as astrocytosis. Studies quantitatively defining the myelin loss in AD are scarce. The aim was to develop a method that could provide numerical values of myelin density in AD. The purpose was to compare the myelin contents in increasing grades of pathology of WMD, with age and cortical AD pathology as well as in different regions of the brain in AD. MATERIAL AND METHODS Sixteen cases with AD and concomitant WMD were investigated with an in-house developed image analysis technique to determine the myelin attenuation with optical density (OD) in frontoparietal, parietal, temporal and occipital white matter on whole brain coronal sections stained for myelin with Luxol Fast Blue (LFB). The OD values in LFB were compared grouped according to Haematoxylin/Eosin (HE) evaluated mild, moderate and severe WMD or normal tissue. The OD values were also correlated with age and cortical AD pathology and compared between the different studied white matter regions. RESULTS Increasing severity of WMD was associated with a statistically significant OD reduction. No correlation was seen between age and OD or overall cortical AD pathology. The OD values were significantly lower in frontoparietal-compared to occipital white matter. CONCLUSIONS Myelin loss in AD with WMD is a marked morphologic component of the disease and it is possible to determine the reduction objectively in neuropathological specimens with quantitative measures. This may be of use for clinical diagnostics including brain imaging.
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Affiliation(s)
- Martin Sjöbeck
- Department of Pathology, Division of Neuropathology, University Hospital, Lund, Sweden.
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42
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Narayanan S, Francis SJ, Sled JG, Santos AC, Antel S, Levesque I, Brass S, Lapierre Y, Sappey-Marinier D, Pike GB, Arnold DL. Axonal injury in the cerebral normal-appearing white matter of patients with multiple sclerosis is related to concurrent demyelination in lesions but not to concurrent demyelination in normal-appearing white matter. Neuroimage 2005; 29:637-42. [PMID: 16126413 DOI: 10.1016/j.neuroimage.2005.07.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Accepted: 07/13/2005] [Indexed: 11/26/2022] Open
Abstract
We assessed axonal injury and demyelination in the cerebral normal-appearing white matter (NAWM) of MS patients in a pilot study using proton magnetic resonance spectroscopic imaging and quantitative magnetization transfer (MT) imaging. Resonance intensities of N-acetylaspartate (NAA) relative to creatine (Cr) were measured in a large central brain volume. NAA/Cr in NAWM was estimated by regression of the NAA/Cr in each voxel against white matter fraction and extrapolation to a white matter fraction of 1. The fractional size of the semi-solid pool (F) was obtained from the binary spin bath model of MT by computing the model parameters from multiple MT-weighted and relaxometry acquisitions. F in NAWM was significantly smaller in the patients [0.109 (0.009)] relative to controls [0.123 (0.007), P = 0.011], but did not differ between RR [0.1085] and SP [0.1087] patients [P > 0.99]. NAA/Cr and F in the NAWM were not correlated (r = 0.16, P > 0.7), mainly due to a lack of variation in F among patients. This may indicate a floor to the extent of myelin pathology that can occur in NAWM before a lesion appears, or that axonal damage is not strictly related to demyelination. The correlation between NAWM NAA/Cr and T2w lesion volume was not significant (P > 0.1). However, dividing the lesion volumes by the mean F in T2w lesions resulted in a quantity that correlated well with NAWM NAA/Cr (r = -0.78, P = 0.038), possibly reflecting the association of Wallerian degeneration in the NAWM with axonal transection associated with demyelination within lesions.
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Affiliation(s)
- Sridar Narayanan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada H3A 2B4.
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Fazekas F, Ropele S, Enzinger C, Gorani F, Seewann A, Petrovic K, Schmidt R. MTI of white matter hyperintensities. Brain 2005; 128:2926-32. [PMID: 15958507 DOI: 10.1093/brain/awh567] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The severity of tissue changes associated with incidental white matter hyperintensities (WMH) in the elderly cannot be sufficiently determined by conventional MRI. We, therefore, performed a regional analysis of the magnetization transfer ratio (MTR) maps obtained on a 1.5 T scanner from 198 neurologically asymptomatic participants of the Austrian Stroke Prevention Study (mean age 70, age range 52-87 years) in regard to WMH and predefined areas of normal appearing brain tissue. Fluid attenuated inversion recovery MRI was used to grade lesion severity and for lesion volume measurements. The MTR of WMH was always significantly lower than that of normal appearing white matter (NAWM) with an overall relative reduction of approximately 10% and decreased significantly with increasing scores of WMH severity (P = 0.02) and WMH volume (r = -0.24, P = 0.0016). NAWM MTR was not different between subjects with very few and extensive WMH and the WMH volume was associated with NAWM MTR of the frontal lobes only. Concerning a possible impact on cerebral functioning the MTR of the frontal NAWM was significantly associated with fine motor dexterity (P = 0.04) but not with cognitive performance. A significant decline of the MTR with aging was seen in both NAWM and cortex but not in WMH. We conclude that MTR measurements can serve to quantify WMH associated tissue damage. It is predominantly focal, relatively mild, increases with lesion size and may have remote effects on the frontal white matter.
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Affiliation(s)
- Franz Fazekas
- Department of Neurology, Medical University Graz, Auenbruggerplatz 22, A-8036 Graz, Austria.
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Abstract
Magnetic resonance imaging (MRI) plays an ever-expanding role in the evaluation of multiple sclerosis (MS). This includes its sensitivity for the diagnosis of the disease and its role in identifying patients at high risk for conversion to MS after a first presentation with selected clinically isolated syndromes. In addition, MRI is a key tool in providing primary therapeutic outcome measures for phase I/II trials and secondary outcome measures in phase III trials. The utility of MRI stems from its sensitivity to longitudinal changes including those in overt lesions and, with advanced MRI techniques, in areas affected by diffuse occult disease (the so-called normal-appearing brain tissue). However, all current MRI methodology suffers from limited specificity for the underlying histopathology. Conventional MRI techniques, including lesion detection and measurement of atrophy from T1- or T2-weighted images, have been the mainstay for monitoring disease activity in clinical trials, in which the use of gadolinium with T1-weighted images adds additional sensitivity and specificity for areas of acute inflammation. Advanced imaging methods including magnetization transfer, fluid attenuated inversion recovery, diffusion, magnetic resonance spectroscopy, functional MRI, and nuclear imaging techniques have added to our understanding of the pathogenesis of MS and may provide methods to monitor therapies more sensitively in the future. However, these advanced methods are limited by their cost, availability, complexity, and lack of validation. In this article, we review the role of conventional and advanced imaging techniques with an emphasis on neurotherapeutics.
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Affiliation(s)
- Rohit Bakshi
- Department of Neurology and Radiology, Partners MS Center, Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Karampekios S, Papanikolaou N, Papadaki E, Maris T, Uffman K, Spilioti M, Plaitakis A, Gourtsoyiannis N. Quantification of magnetization transfer rate and native T1 relaxation time of the brain: correlation with magnetization transfer ratio measurements in patients with multiple sclerosis. Neuroradiology 2005; 47:189-96. [PMID: 15711987 DOI: 10.1007/s00234-005-1344-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Accepted: 11/30/2004] [Indexed: 10/25/2022]
Abstract
The purpose of this paper is to perform quantitative measurements of the magnetization transfer rate (Kfor) and native T1 relaxation time (T1free) in the brain tissue of normal individuals and patients with multiple sclerosis (MS) by means of multiple gradient echo acquisitions, and to correlate these measurements with the magnetization transfer ratio (MTR). Quantitative magnetization transfer imaging was performed in five normal volunteers and 12 patients with relapsing-remitting MS on a 1.5 T magnetic resonance (MR) scanner. The T1 relaxation time under magnetization transfer irradiation (T1sat) was calculated by means of fitting the signal intensity over the flip angle in several 3D spoiled gradient echo acquisitions (3 degrees , 15 degrees , 30 degrees , and 60 degrees ), while a single acquisition without MT irradiation (flip angle of 3 degrees ) was utilized to calculate the MTR. The Kfor and T1free constants were quantified on a pixel-by-pixel basis and parametric maps were reconstructed. We performed 226 measurements of Kfor, T1free, and the MTR on normal white matter (NWM) of healthy volunteers (n=50), and normal-appearing white matter (NAWM) and pathological brain areas of MS patients (n=120 and 56, respectively). Correlation coefficients between Kfor-MTR, T1free-MTR, and T1free-Kfor were calculated. Lesions were classified, according to their characteristics on T1-weighted images, into isointense (compared to white matter), mildly hypointense (showing signal intensity lower than white matter and higher than gray matter), and severely hypointense (revealing signal intensity lower than gray matter). "Dirty" white matter (DWM) corresponded to areas with diffused high signal, as identified on T2-weighted images. Strong correlation coefficients were obtained between MTR and Kfor for all lesions studied (r2=0.9, p<0.0001), for mildly hypointense plaques (r2=0.82, p<0.0001), and for DWM (r2=0.78, p=0.0007). In contrast, comparison between MTR and T1free values yielded rather low correlation coefficients for all groups assessed. In severely hypointense lesions, an excellent correlation was found between Kfor and T1free measurements (r2=0.98, p<0.0001). Strong correlations between Kfor and T1free were found for the rest of the subgroups, except for the NAWM, in which a moderate correlation was obtained (r2=0.5, p<0.0001). We conclude that Kfor and T1free measurements are feasible and may improve our understanding of the pathological brain changes that occur in MS patients.
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Affiliation(s)
- Spyros Karampekios
- Department of Radiology, University Hospital of Heraklion, University of Crete, P.O. Box 1352, Heraklion, Crete, 71110, Greece.
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46
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Broom KA, Anthony DC, Blamire AM, Waters S, Styles P, Perry VH, Sibson NR. MRI reveals that early changes in cerebral blood volume precede blood-brain barrier breakdown and overt pathology in MS-like lesions in rat brain. J Cereb Blood Flow Metab 2005; 25:204-16. [PMID: 15678123 DOI: 10.1038/sj.jcbfm.9600020] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Magnetic resonance imaging (MRI) is an established clinical tool for diagnosing multiple sclerosis (MS), the archetypal central nervous system neuroinflammatory disease. In this study, we have used a model of delayed-type hypersensitivity in the rat brain, which bears many of the hallmarks of an MS lesion, to investigate the development of MRI-detectable changes before the appearance of conventional indices of lesion development. In addition, we have correlated the MRI-detectable changes with the developing histopathology. Significant increases in regional cerebral blood volume (rCBV) preceded overt changes in blood-brain barrier (BBB) permeability, T2 relaxation and the diffusion properties of tissue water. Thus, changes in rCBV might be a more sensitive indicator of lesion onset than the conventional indices used clinically in MS patients, such as contrast enhancement. In addition, we show that BBB breakdown, and consequent edema formation, are more closely correlated with astrogliosis than any other histopathologic changes, while regions of T1 and T2 hypointensity appear to reflect hypercellularity.
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Affiliation(s)
- Kerry A Broom
- Experimental Neuroimaging Group, Department of Biochemistry, University of Oxford, Oxford, UK.
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47
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Ropele S, Filippi M, Valsasina P, Korteweg T, Barkhof F, Tofts PS, Samson R, Miller DH, Fazekas F. Assessment and correction ofB1-induced errors in magnetization transfer ratio measurements. Magn Reson Med 2004; 53:134-40. [PMID: 15690512 DOI: 10.1002/mrm.20310] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The magnetization transfer ratio (MTR) is strongly related to the field strength (B(1)) of the saturation pulse. B(1) variations therefore can result in significant MTR variations and can affect histogram analysis, particularly if data from a large volume of interest are included. A multicenter study was performed to determine the typical range of B(1) errors and the corresponding MTR variations in brain tissue of healthy volunteers. Seven subjects were included at each center resulting in a total cohort of 28 subjects. Additionally, numerical simulations were done to study this relationship more generally for pulsed saturation. It could be demonstrated, both theoretically and empirically, that for typical B(1) errors there is a linear relationship between B(1) error and the corresponding MTR change. In addition, for proton density-weighted sequences, this relationship seems to be largely independent of the underlying relaxation properties. Mean B(1) errors in the entire brain were typically in the range between -3% and -7%. Due to different coil characteristics, significant MTR differences between different scanners and sites were observed. Using a simple correction scheme that is based on a linear regression analysis between MTR and B(1) data it was possible to reduce the intersubject variation by approximately 50%. Furthermore, interscanner variation could be reduced such that no significant differences between scanners could be detected. The correction scheme may be useful when investigating MTR as an outcome measure in single or multicenter studies.
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Affiliation(s)
- Stefan Ropele
- MR Research Unit, Medical University Graz, Auenbruggerplatz 9, A-8036 Graz, Austria.
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48
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Filippi M, Rocca MA, Comi G. The use of quantitative magnetic-resonance-based techniques to monitor the evolution of multiple sclerosis. Lancet Neurol 2003; 2:337-46. [PMID: 12849150 DOI: 10.1016/s1474-4422(03)00408-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Conventional MRI can improve accuracy in the diagnosis of multiple sclerosis (MS) and monitor the efficacy of experimental treatments. However, conventional MRI provides only gross estimates of the extent and nature of tissue damage associated with this disease. Other quantitative magnetic-resonance-based techniques have the potential to overcome the limitations of conventional MRI and, as a consequence, to improve our understanding of the natural history of MS. Magnetisation-transfer, diffusion-weighted, and functional MRI--as well as proton magnetic-resonance spectroscopy--are helping us to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. These techniques are substantially changing our understanding of how MS causes irreversible disability and should be used more extensively in clinical trials and in studies of disease progression.
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Affiliation(s)
- Massimo Filippi
- Department of Neurology, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
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49
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Bagnato F, Frank JA. The role of nonconventional magnetic resonance imaging techniques in demyelinating disorders. Curr Neurol Neurosci Rep 2003; 3:238-45. [PMID: 12691629 DOI: 10.1007/s11910-003-0084-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The use of nonconventional magnetic resonance imaging techniques (eg, magnetization transfer, magnetic resonance spectroscopy, and diffusion weighted imaging) allows for an accurate characterization of lesions as compared with conventional or standard approaches in demyelinating diseases. Magnetization transfer, magnetic resonance spectroscopy, and diffusion weighted imaging have revolutionized our understanding of demyelinating diseases because these techniques have been used to identify pathologic changes of normal-appearing brain tissue and characterize the differences in lesions. Metrics derived from these methods correlate with clinical disability and provide more accurate tools for monitoring disease activity and treatment effect over time. Quantitative T1 and T2 relaxation time maps provide additional information on demyelinating diseases, allowing for the evaluation of myelin water and distribution of water within tissues. Finally, the measurement of central nervous system atrophy has become a valuable element in determining the course of multiple sclerosis.
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Affiliation(s)
- Francesca Bagnato
- Neuroimmunology Branch, National Institutes for Neurological Disease and Stroke, National Institutes of Health, Building 10, Room 5B16, 10 Center Drive MSC 1400, Bethesda, MD 20892-1400, USA.
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