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Ineichen BV, Okar SV, Proulx ST, Engelhardt B, Lassmann H, Reich DS. Perivascular spaces and their role in neuroinflammation. Neuron 2022; 110:3566-3581. [PMID: 36327898 PMCID: PMC9905791 DOI: 10.1016/j.neuron.2022.10.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 08/17/2022] [Accepted: 10/13/2022] [Indexed: 11/19/2022]
Abstract
It is uncontested that perivascular spaces play critical roles in maintaining homeostasis and priming neuroinflammation. However, despite more than a century of intense research on perivascular spaces, many open questions remain about the anatomical compartment surrounding blood vessels within the CNS. The goal of this comprehensive review is to summarize the literature on perivascular spaces in human neuroinflammation and associated animal disease models. We describe the cell types taking part in the morphological and functional aspects of perivascular spaces and how those spaces can be visualized. Based on this, we propose a model of the cascade of events occurring during neuroinflammatory pathology. We also discuss current knowledge gaps and limitations of the available evidence. An improved understanding of perivascular spaces could advance our comprehension of the pathophysiology of neuroinflammation and open a new therapeutic window for neuroinflammatory diseases such as multiple sclerosis.
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Affiliation(s)
- Benjamin V Ineichen
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland; Center for Reproducible Science, University of Zurich, Zurich, Switzerland.
| | - Serhat V Okar
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Steven T Proulx
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | | | - Hans Lassmann
- Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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2
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Dal-Bianco A, Schranzer R, Grabner G, Lanzinger M, Kolbrink S, Pusswald G, Altmann P, Ponleitner M, Weber M, Kornek B, Zebenholzer K, Schmied C, Berger T, Lassmann H, Trattnig S, Hametner S, Leutmezer F, Rommer P. Iron Rims in Patients With Multiple Sclerosis as Neurodegenerative Marker? A 7-Tesla Magnetic Resonance Study. Front Neurol 2022; 12:632749. [PMID: 34992573 PMCID: PMC8724313 DOI: 10.3389/fneur.2021.632749] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: Multiple sclerosis (MS) is a demyelinating and neurodegenerative disease of the central nervous system, characterized by inflammatory-driven demyelination. Symptoms in MS manifest as both physical and neuropsychological deficits. With time, inflammation is accompanied by neurodegeneration, indicated by brain volume loss on an MRI. Here, we combined clinical, imaging, and serum biomarkers in patients with iron rim lesions (IRLs), which lead to severe tissue destruction and thus contribute to the accumulation of clinical disability. Objectives: Subcortical atrophy and ventricular enlargement using an automatic segmentation pipeline for 7 Tesla (T) MRI, serum neurofilament light chain (sNfL) levels, and neuropsychological performance in patients with MS with IRLs and non-IRLs were assessed. Methods: In total 29 patients with MS [15 women, 24 relapsing-remitting multiple sclerosis (RRMS), and five secondary-progressive multiple sclerosis (SPMS)] aged 38 (22–69) years with an Expanded Disability Status Score of 2 (0–8) and a disease duration of 11 (5–40) years underwent neurological and neuropsychological examinations. Volumes of lesions, subcortical structures, and lateral ventricles on 7-T MRI (SWI, FLAIR, and MP2RAGE, 3D Segmentation Software) and sNfL concentrations using the Simoa SR-X Analyzer in IRL and non-IRL patients were assessed. Results: (1) Iron rim lesions patients had a higher FLAIR lesion count (p = 0.047). Patients with higher MP2Rage lesion volume exhibited more IRLs (p <0.014) and showed poorer performance in the information processing speed tested within 1 year using the Symbol Digit Modalities Test (SDMT) (p <0.047). (2) Within 3 years, patients showed atrophy of the thalamus (p = 0.021) and putamen (p = 0.043) and enlargement of the lateral ventricles (p = 0.012). At baseline and after 3 years, thalamic volumes were lower in IRLs than in non-IRL patients (p = 0.045). (3) At baseline, IRL patients had higher sNfL concentrations (p = 0.028). Higher sNfL concentrations were associated with poorer SDMT (p = 0.004), regardless of IRL presence. (4) IRL and non-IRL patients showed no significant difference in the neuropsychological performance within 1 year. Conclusions: Compared with non-IRL patients, IRL patients had higher FLAIR lesion counts, smaller thalamic volumes, and higher sNfL concentrations. Our pilot study combines IRL and sNfL, two biomarkers considered indicative for neurodegenerative processes. Our preliminary data underscore the reported destructive nature of IRLs.
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Affiliation(s)
| | - R Schranzer
- Department of Neurology, Vienna, Austria.,Department of Medical Engineering, Carinthia University of Applied Sciences, Klagenfurt, Austria
| | - G Grabner
- Department of Neurology, Vienna, Austria.,Department of Medical Engineering, Carinthia University of Applied Sciences, Klagenfurt, Austria
| | | | - S Kolbrink
- Department of Neurology, Vienna, Austria
| | - G Pusswald
- Department of Neurology, Vienna, Austria
| | - P Altmann
- Department of Neurology, Vienna, Austria
| | | | - M Weber
- Department of Biomedical Imaging and Image-Guided Therapy, High Field Magnetic Resonance Centre, Vienna, Austria
| | - B Kornek
- Department of Neurology, Vienna, Austria
| | | | - C Schmied
- Department of Neurology, Vienna, Austria
| | - T Berger
- Department of Neurology, Vienna, Austria
| | - H Lassmann
- Department of Neuroimmunology, Center for Brain Research, Vienna, Austria
| | - S Trattnig
- Department of Biomedical Imaging and Image-Guided Therapy, High Field Magnetic Resonance Centre, Vienna, Austria
| | - S Hametner
- Department of Neurology, Vienna, Austria.,Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | | | - P Rommer
- Department of Neurology, Vienna, Austria
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3
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Ineichen BV, Beck ES, Piccirelli M, Reich DS. New Prospects for Ultra-High-Field Magnetic Resonance Imaging in Multiple Sclerosis. Invest Radiol 2021; 56:773-784. [PMID: 34120128 PMCID: PMC8505164 DOI: 10.1097/rli.0000000000000804] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/09/2021] [Accepted: 05/09/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT There is growing interest in imaging multiple sclerosis (MS) through the ultra-high-field (UHF) lens, which currently means a static magnetic field strength of 7 T or higher. Because of higher signal-to-noise ratio and enhanced susceptibility effects, UHF magnetic resonance imaging improves conspicuity of MS pathological hallmarks, among them cortical demyelination and the central vein sign. This could, in turn, improve confidence in MS diagnosis and might also facilitate therapeutic monitoring of MS patients. Furthermore, UHF imaging offers unique insight into iron-related pathology, leptomeningeal inflammation, and spinal cord pathologies in neuroinflammation. Yet, limitations such as the longer scanning times to achieve improved resolution and incipient safety data on implanted medical devices need to be considered. In this review, we discuss applications of UHF imaging in MS, its advantages and limitations, and practical aspects of UHF in the clinical setting.
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Affiliation(s)
- Benjamin V. Ineichen
- From the Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Erin S. Beck
- From the Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Marco Piccirelli
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Daniel S. Reich
- From the Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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4
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Eckstein K, Bachrata B, Hangel G, Widhalm G, Enzinger C, Barth M, Trattnig S, Robinson SD. Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI. Neuroimage 2021; 237:118175. [PMID: 34000407 PMCID: PMC7612087 DOI: 10.1016/j.neuroimage.2021.118175] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/28/2021] [Accepted: 05/13/2021] [Indexed: 02/07/2023] Open
Abstract
Purpose Susceptibility Weighted Imaging (SWI) has become established in the clinical investigation of stroke, microbleeds, tumor vascularization, calcification and iron deposition, but suffers from a number of shortcomings and artefacts. The goal of this study was to reduce the sensitivity of SWI to strong B1 and B0 inhomogeneities at ultra-high field to generate homogeneous images with increased contrast and free of common artefacts. All steps in SWI processing have been addressed −coil combination, phase unwrapping, image combination over echoes, phase filtering and homogeneity correction −and applied to an efficient bipolar multi-echo acquisition to substantially improve the quality of SWI. Principal results Our findings regarding the optimal individual processing steps lead us to propose a Contrast-weighted, Laplace-unwrapped, bipolar multi-Echo, ASPIRE-combined, homogeneous, improved Resolution SWI, or CLEAR-SWI. CLEAR-SWI was compared to two other multi-echo SWI methods and standard, single-echo SWI with the same acquisition time at 7 T in 10 healthy volunteers and with single-echo SWI in 13 patients with brain tumors. CLEAR-SWI had improved contrast-to-noise and homogeneity, reduced signal dropout and was not compromised by the artefacts which affected standard SWI in 10 out of 13 cases close to tumors (as assessed by expert raters), as well as generating T2* maps and phase images which can be used for Quantitative Susceptibility Mapping. In a comparison with other multi-echo SWI methods, CLEAR-SWI had the fewest artefacts, highest SNR and generally higher contrast-to-noise. Major conclusions CLEAR-SWI eliminates the artefacts common in standard, single-echo SWI, reduces signal dropouts and improves image homogeneity and contrast-to-noise. Applied clinically, in a study of brain tumor patients, CLEAR-SWI was free of the artefacts which affected standard, single-echo SWI.
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Affiliation(s)
- Korbinian Eckstein
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Beata Bachrata
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria
| | - Gilbert Hangel
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Georg Widhalm
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | | | - Markus Barth
- School of Information Technology and Electrical Engineering, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, Australia
| | - Siegfried Trattnig
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria
| | - Simon Daniel Robinson
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria; Department of Neurology, Medical University of Graz, Graz, Austria; Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia
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5
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Dal-Bianco A, Grabner G, Kronnerwetter C, Weber M, Kornek B, Kasprian G, Berger T, Leutmezer F, Rommer PS, Trattnig S, Lassmann H, Hametner S. Long-term evolution of multiple sclerosis iron rim lesions in 7 T MRI. Brain 2021; 144:833-847. [PMID: 33484118 DOI: 10.1093/brain/awaa436] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 01/10/2023] Open
Abstract
Recent data suggest that multiple sclerosis white matter lesions surrounded by a rim of iron containing microglia, termed iron rim lesions, signify patients with more severe disease course and a propensity to develop progressive multiple sclerosis. So far, however, little is known regarding the dynamics of iron rim lesions over long-time follow-up. In a prospective longitudinal cohort study in 33 patients (17 females; 30 relapsing-remitting, three secondary progressive multiple sclerosis; median age 36.6 years (18.6-62.6), we characterized the evolution of iron rim lesions by MRI at 7 T with annual scanning. The longest follow-up was 7 years in a subgroup of eight patients. Median and mean observation period were 1 (0-7) and 2.9 (±2.6) years, respectively. Images were acquired using a fluid-attenuated inversion recovery sequence fused with iron-sensitive MRI phase data, termed FLAIR-SWI, as well as a magnetization prepared two rapid acquisition gradient echoes, termed MP2RAGE. Volumes and T1 relaxation times of lesions with and without iron rims were assessed by manual segmentation. The pathological substrates of periplaque signal changes outside the iron rims were corroborated by targeted histological analysis on 17 post-mortem cases (10 females; two relapsing-remitting, 13 secondary progressive and two primary progressive multiple sclerosis; median age 66 years (34-88), four of them with available post-mortem 7 T MRI data. We observed 16 nascent iron rim lesions, which mainly formed in relapsing-remitting multiple sclerosis. Iron rim lesion fraction was significantly higher in relapsing-remitting than progressive disease (17.8 versus 7.2%; P < 0.001). In secondary progressive multiple sclerosis only, iron rim lesions showed significantly different volume dynamics (P < 0.034) compared with non-rim lesions, which significantly shrank with time in both relapsing-remitting (P < 0.001) and secondary progressive multiple sclerosis (P < 0.004). The iron rims themselves gradually diminished with time (P < 0.008). Compared with relapsing-remitting multiple sclerosis, iron rim lesions in secondary progressive multiple sclerosis were significantly more destructive than non-iron rim lesions (P < 0.001), reflected by prolonged lesional T1 relaxation times and by progressively increasing changes ascribed to secondary axonal degeneration in the periplaque white matter. Our study for the first time shows that chronic active lesions in multiple sclerosis patients evolve over many years after their initial formation. The dynamics of iron rim lesions thus provide one explanation for progressive brain damage and disability accrual in patients. Their systematic recording might become useful as a tool for predicting disease progression and monitoring treatment in progressive multiple sclerosis.
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Affiliation(s)
| | - Günther Grabner
- Department of Neurology, Medical University of Vienna, Austria.,Department of Medical Engineering, Carinthia University of Applied Sciences, Klagenfurt, Austria
| | - Claudia Kronnerwetter
- Biomedical Imaging and Image-guided Therapy, High Field MR Center, Medical University of Vienna, Austria
| | - Michael Weber
- Biomedical Imaging and Image-guided Therapy, High Field MR Center, Medical University of Vienna, Austria
| | - Barbara Kornek
- Department of Neurology, Medical University of Vienna, Austria
| | - Gregor Kasprian
- Biomedical Imaging and Image-guided Therapy, High Field MR Center, Medical University of Vienna, Austria
| | - Thomas Berger
- Department of Neurology, Medical University of Vienna, Austria
| | - Fritz Leutmezer
- Department of Neurology, Medical University of Vienna, Austria
| | | | - Siegfried Trattnig
- Biomedical Imaging and Image-guided Therapy, High Field MR Center, Medical University of Vienna, Austria
| | - Hans Lassmann
- Center for Brain Research, Medical University of Vienna, Austria
| | - Simon Hametner
- Department of Neurology, Medical University of Vienna, Austria
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6
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Haacke EM, Ge Y, Sethi SK, Buch S, Zamboni P. An Overview of Venous Abnormalities Related to the Development of Lesions in Multiple Sclerosis. Front Neurol 2021; 12:561458. [PMID: 33981281 PMCID: PMC8107266 DOI: 10.3389/fneur.2021.561458] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 03/26/2021] [Indexed: 12/21/2022] Open
Abstract
The etiology of multiple sclerosis (MS) is currently understood to be autoimmune. However, there is a long history and growing evidence for disrupted vasculature and flow within the disease pathology. A broad review of the literature related to vascular effects in MS revealed a suggestive role for abnormal flow in the medullary vein system. Evidence for venous involvement in multiple sclerosis dates back to the early pathological work by Charcot and Bourneville, in the mid-nineteenth century. Pioneering work by Adams in the 1980s demonstrated vasculitis within the walls of veins and venules proximal to active MS lesions. And more recently, magnetic resonance imaging (MRI) has been used to show manifestations of the central vein as a precursor to the development of new MS lesions, and high-resolution MRI using Ferumoxytol has been used to reveal the microvasculature that has previously only been demonstrated in cadaver brains. Both approaches may shed new light into the structural changes occurring in MS lesions. The material covered in this review shows that multiple pathophysiological events may occur sequentially, in parallel, or in a vicious circle which include: endothelial damage, venous collagenosis and fibrin deposition, loss of vessel compliance, venous hypertension, perfusion reduction followed by ischemia, medullary vein dilation and local vascular remodeling. We come to the conclusion that a potential source of MS lesions is due to locally disrupted flow which in turn leads to remodeling of the medullary veins followed by endothelial damage with the subsequent escape of glial cells, cytokines, etc. These ultimately lead to the cascade of inflammatory and demyelinating events which ensue in the course of the disease.
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Affiliation(s)
- E. Mark Haacke
- Department of Radiology, Wayne State University, Detroit, MI, United States
| | - Yulin Ge
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, United States
| | - Sean K. Sethi
- Department of Radiology, Wayne State University, Detroit, MI, United States
| | - Sagar Buch
- Department of Radiology, Wayne State University, Detroit, MI, United States
| | - Paolo Zamboni
- Vascular Diseases Center, University of Ferrara, Ferrara, Italy
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7
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Lopatina A, Ropele S, Sibgatulin R, Reichenbach JR, Güllmar D. Investigation of Deep-Learning-Driven Identification of Multiple Sclerosis Patients Based on Susceptibility-Weighted Images Using Relevance Analysis. Front Neurosci 2020; 14:609468. [PMID: 33390890 PMCID: PMC7775402 DOI: 10.3389/fnins.2020.609468] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/30/2020] [Indexed: 01/22/2023] Open
Abstract
The diagnosis of multiple sclerosis (MS) is usually based on clinical symptoms and signs of damage to the central nervous system, which is assessed using magnetic resonance imaging. The correct interpretation of these data requires excellent clinical expertise and experience. Deep neural networks aim to assist clinicians in identifying MS using imaging data. However, before such networks can be integrated into clinical workflow, it is crucial to understand their classification strategy. In this study, we propose to use a convolutional neural network to identify MS patients in combination with attribution algorithms to investigate the classification decisions. The network was trained using images acquired with susceptibility-weighted imaging (SWI), which is known to be sensitive to the presence of paramagnetic iron components and is routinely applied in imaging protocols for MS patients. Different attribution algorithms were used to the trained network resulting in heatmaps visualizing the contribution of each input voxel to the classification decision. Based on the quantitative image perturbation method, we selected DeepLIFT heatmaps for further investigation. Single-subject analysis revealed veins and adjacent voxels as signs for MS, while the population-based study revealed relevant brain areas common to most subjects in a class. This pattern was found to be stable across different echo times and also for a multi-echo trained network. Intensity analysis of the relevant voxels revealed a group difference, which was found to be primarily based on the T1w magnitude images, which are part of the SWI calculation. This difference was not observed in the phase mask data.
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Affiliation(s)
- Alina Lopatina
- Medical Physics Group, Institute for Diagnostic and Interventional Radiology, University Hospital Jena, Jena, Germany.,Michael-Stifel-Center for Data-Driven and Simulation Science Jena, Jena, Germany
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Renat Sibgatulin
- Medical Physics Group, Institute for Diagnostic and Interventional Radiology, University Hospital Jena, Jena, Germany
| | - Jürgen R Reichenbach
- Medical Physics Group, Institute for Diagnostic and Interventional Radiology, University Hospital Jena, Jena, Germany.,Michael-Stifel-Center for Data-Driven and Simulation Science Jena, Jena, Germany.,Center of Medical Optics and Photonics Jena, Jena, Germany
| | - Daniel Güllmar
- Medical Physics Group, Institute for Diagnostic and Interventional Radiology, University Hospital Jena, Jena, Germany
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8
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Weber CE, Kraemer M, Dabringhaus A, Ebert A, Platten M, Gass A, Eisele P. Venous Diameter Changes in Chronic Active Multiple Sclerosis Lesions. J Neuroimaging 2020; 31:394-400. [PMID: 33270952 DOI: 10.1111/jon.12818] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE To investigate the temporal evolution of venous diameter in chronic active and nonenhancing shrinking multiple sclerosis (MS) lesions in a longitudinal magnetic resonance imaging (MRI) study including susceptibility-weighted images (SWI). METHODS We compared the venous diameter in chronic active and nonenhancing shrinking lesions to the venous diameter in nonenhancing stable lesions on two 3 T MRI data sets obtained 12 months apart. Chronic active and nonenhancing shrinking lesions were identified by Voxel-Guided Morphometry. Coregistered, overlaid fluid-attenuated inversion recovery/SWI were analyzed for the presence of a central vein. Quantitative calculation of the venous diameter for each time point was performed on the reconstructed veins. RESULTS Sixty-two relapsing-remitting MS patients (50 women; mean age: 36 ± 11 years; mean disease duration: 4 ± 7 years) were included in the study. Overall, we identified 222 chronic MS lesions (48 chronic active, 48 shrinking, 126 stable) with a corresponding intralesional central vein. On baseline MRI, the mean venous diameter did not statistically differ between all subgroups, whereas on follow-up MRI, the mean intralesional venous diameter was smaller in chronic active (0.92 ± 0.15 mm) and shrinking lesions (0.90 ± 0.19 mm) compared to stable lesions (1.10 ± 0.18 mm; P < .001). CONCLUSION Our findings demonstrate venous narrowing in chronic active and nonenhancing shrinking MS lesions. The smaller diameter of intralesional veins during follow up in these lesions may reflect structural, degenerative, and metabolic changes due to chronic inflammation, (perivascular) fibrosis, collagenous thickening, and increased levels of oxygenated hemoglobin.
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Affiliation(s)
- Claudia E Weber
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
| | - Matthias Kraemer
- Department of Neurology and Neurological Early Rehabilitation, Hospital zum Heiligen Geist, Kempen, Germany
| | - Andreas Dabringhaus
- Deutsches Institut für Medizinische Dokumentation und Information, Köln, Germany
| | - Anne Ebert
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
| | - Michael Platten
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
| | - Achim Gass
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
| | - Philipp Eisele
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
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9
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Castellaro M, Tamanti A, Pisani AI, Pizzini FB, Crescenzo F, Calabrese M. The Use of the Central Vein Sign in the Diagnosis of Multiple Sclerosis: A Systematic Review and Meta-analysis. Diagnostics (Basel) 2020; 10:diagnostics10121025. [PMID: 33260401 PMCID: PMC7760678 DOI: 10.3390/diagnostics10121025] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 11/26/2020] [Accepted: 11/26/2020] [Indexed: 02/01/2023] Open
Abstract
Background: The central vein sign (CVS) is a radiological feature proposed as a multiple sclerosis (MS) imaging biomarker able to accurately differentiate MS from other white matter diseases of the central nervous system. In this work, we evaluated the pooled proportion of the CVS in brain MS lesions and to estimate the diagnostic performance of CVS to perform a diagnosis of MS and propose an optimal cut-off value. Methods: A systematic search was performed on publicly available databases (PUBMED/MEDLINE and Web of Science) up to 24 August 2020. Analysis of the proportion of white matter MS lesions with a central vein was performed using bivariate random-effect models. A meta-regression analysis was performed and the impact of using particular sequences (such as 3D echo-planar imaging) and post-processing techniques (such as FLAIR*) was investigated. Pooled sensibility and specificity were estimated using bivariate models and meta-regression was performed to address heterogeneity. Inclusion and publication bias were assessed using asymmetry tests and a funnel plot. A hierarchical summary receiver operating curve (HSROC) was used to estimate the summary accuracy in diagnostic performance. The Youden index was employed to estimate the optimal cut-off value using individual patient data. Results: The pooled proportion of lesions showing a CVS in the MS population was 73%. The use of the CVS showed a remarkable diagnostic performance in MS cases, providing a pooled specificity of 92% and a sensitivity of 95%. The optimal cut-off value obtained from the individual patient data pooled together was 40% with excellent accuracy calculated by the area under the ROC (0.946). The 3D-EPI sequences showed both a higher pooled proportion compared to other sequences and explained heterogeneity in the meta-regression analysis of diagnostic performances. The 1.5 Tesla (T) scanners showed a lower (58%) proportion of MS lesions with a CVS compared to both 3T (74%) and 7T (82%). Conclusions: The meta-analysis we have performed shows that the use of the CVS in differentiating MS from other mimicking diseases is encouraged; moreover, the use of dedicated sequences such as 3D-EPI and the high MRI field is beneficial.
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Affiliation(s)
- Marco Castellaro
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (A.T.); (A.I.P.); (F.C.); (M.C.)
- Correspondence:
| | - Agnese Tamanti
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (A.T.); (A.I.P.); (F.C.); (M.C.)
| | - Anna Isabella Pisani
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (A.T.); (A.I.P.); (F.C.); (M.C.)
| | | | - Francesco Crescenzo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (A.T.); (A.I.P.); (F.C.); (M.C.)
| | - Massimiliano Calabrese
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (A.T.); (A.I.P.); (F.C.); (M.C.)
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10
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Bruschi N, Boffa G, Inglese M. Ultra-high-field 7-T MRI in multiple sclerosis and other demyelinating diseases: from pathology to clinical practice. Eur Radiol Exp 2020; 4:59. [PMID: 33089380 PMCID: PMC7578213 DOI: 10.1186/s41747-020-00186-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 09/11/2020] [Indexed: 11/10/2022] Open
Abstract
Magnetic resonance imaging (MRI) is essential for the early diagnosis of multiple sclerosis (MS), for investigating the disease pathophysiology, and for discriminating MS from other neurological diseases. Ultra-high-field strength (7-T) MRI provides a new tool for studying MS and other demyelinating diseases both in research and in clinical settings. We present an overview of 7-T MRI application in MS focusing on increased sensitivity and specificity for lesion detection and characterisation in the brain and spinal cord, central vein sign identification, and leptomeningeal enhancement detection. We also discuss the role of 7-T MRI in improving our understanding of MS pathophysiology with the aid of metabolic imaging. In addition, we present 7-T MRI applications in other demyelinating diseases. 7-T MRI allows better detection of the anatomical, pathological, and functional features of MS, thus improving our understanding of MS pathology in vivo. 7-T MRI also represents a potential tool for earlier and more accurate diagnosis.
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Affiliation(s)
- Nicolo' Bruschi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
| | - Giacomo Boffa
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
| | - Matilde Inglese
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy.
- Ospedale Policlinico San Martino, IRCCS, Largo Daneo 3, 16100, Genoa, Italy.
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11
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Investigation of the “central vein sign” in infratentorial multiple sclerosis lesions. Mult Scler Relat Disord 2020; 45:102409. [DOI: 10.1016/j.msard.2020.102409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 11/20/2022]
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12
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Developmental Venous Anomalies are More Common in Patients with Multiple Sclerosis and Clinically Isolated Syndrome : Coincidence or Relevant? Clin Neuroradiol 2020; 31:225-234. [PMID: 31897504 DOI: 10.1007/s00062-019-00869-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE Developmental venous anomalies (DVA) are congenital malformations of veins that drain brain parenchyma, with a prevalence up to 9.3% in normal populations and 29.5% in multiple sclerosis (MS) patients. Study purpose was to determine prevalence of DVAs in patients with clinically isolated syndrome (CIS) and early relapsing-remitting multiple sclerosis (RRMS) and to assess whether DVAs are related to altered clinical, magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) laboratory parameters. METHODS Routine neurological and MRI examinations took place in a single center in 93 patients (39 CIS, 54 RRMS). Clinical disability (n = 93), MRI (n ≤ 90), CSF (n ≤ 82) parameters and DVA status were determined and compared statistically. RESULTS A total of 29 DVAs were detected in 25 patients (25/93; 26.9%), 10 in 39 CIS patients and 15 in 54 RRMS patients. Most parameters were not significantly altered in patients with DVAs; no associated higher conversion rates from CIS to MS at 1-year (p = 0.411) or 2‑year follow-up (p = 0.281) were registered. CONCLUSION A higher prevalence of DVAs was detected in CIS and early MS patients than reported in non-MS populations, congruent to recent literature. The DVAs were not associated with significantly altered clinical outcomes, brain atrophy rates or disease progression, and no associated higher risk of CIS patients for converting to MS was found.
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13
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Susceptibility-weighted imaging in the differential diagnosis of autoimmune central nervous system vasculitis and multiple sclerosis. Mult Scler Relat Disord 2019; 33:70-74. [DOI: 10.1016/j.msard.2019.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/05/2019] [Accepted: 05/19/2019] [Indexed: 11/17/2022]
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14
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Hametner S, Dal Bianco A, Trattnig S, Lassmann H. Iron related changes in MS lesions and their validity to characterize MS lesion types and dynamics with Ultra-high field magnetic resonance imaging. Brain Pathol 2019; 28:743-749. [PMID: 30020556 PMCID: PMC8028547 DOI: 10.1111/bpa.12643] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 06/12/2018] [Indexed: 12/31/2022] Open
Abstract
Iron accumulates with age in the normal human brain. This process is altered at several levels in the brain of multiple sclerosis (MS) patients. Since iron is mainly stored in oligodendrocytes and myelin in the normal brain, its liberation in demyelinating lesions may amplify tissue damage in demyelinating lesions and its uptake in macrophages and microglia may help to more precisely define activity stages of the lesions. In addition, glia cells change their iron import, export and storage properties in MS lesions, which is reflected by alterations in the expression of iron transport molecules. Changes of iron distribution in the brain can be reliably detected by MRI, particularly upon application of Ultra‐high magnetic field (7 Tesla). Iron‐sensitive MRI allows to more accurately distinguish the lesions in MS from those in other inflammatory brain diseases, to visualize a subset of slowly expanding lesions in the progressive stage of MS and to increase the sensitivity for lesion detection in the gray matter, such as the cerebral cortex or deep gray matter nuclei.
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Affiliation(s)
- Simon Hametner
- Center for Brain Research, Medical University of Vienna, Austria.,Institute of Neuropathology, University of Göttingen, Germany
| | - Assunta Dal Bianco
- Center for Brain Research, Medical University of Vienna, Austria.,Department of Neurology, Medical University of Vienna, Austria
| | - Siegfried Trattnig
- Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Austria
| | - Hans Lassmann
- Center for Brain Research, Medical University of Vienna, Austria
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15
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Ladd ME, Bachert P, Meyerspeer M, Moser E, Nagel AM, Norris DG, Schmitter S, Speck O, Straub S, Zaiss M. Pros and cons of ultra-high-field MRI/MRS for human application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:1-50. [PMID: 30527132 DOI: 10.1016/j.pnmrs.2018.06.001] [Citation(s) in RCA: 275] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI. In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioural Brain Sciences, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Sina Straub
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz Zaiss
- High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany.
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16
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Gabr RE, Pednekar AS, Kamali A, Lincoln JA, Nelson FM, Wolinsky JS, Narayana PA. Interleaved susceptibility-weighted and FLAIR MRI for imaging lesion-penetrating veins in multiple sclerosis. Magn Reson Med 2018; 80:1132-1137. [PMID: 29334139 PMCID: PMC5980669 DOI: 10.1002/mrm.27091] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 12/27/2017] [Indexed: 11/10/2022]
Abstract
Purpose To simultaneously image brain lesions and veins in multiple sclerosis. Methods An interleaved sequence was developed to simultaneously acquire 3D T2*-weighted (or susceptibility-weighted, SW) and fluid-attenuated inversion recovery (FLAIR) images on a 3.0T MRI system. The pulse sequence parameters were calculated to minimize signal perturbation from steady state while maintaining acceptable image contrast and scan time. Fifteen multiple sclerosis patients were enrolled in this prospective study and underwent a standard MS imaging protocol. In addition, SW and FLAIR images were acquired separately and also in an interleaved manner. The SW and FLAIR images were combined into one image to visualize lesions and penetrating veins. The contrast ratios between white matter lesions and penetrating veins were compared between the interleaved sequence and the individual non-interleaved acquisitions. Results Interleaved scanning of the FLAIR and the SW pulse sequences was achieved, producing aligned images, and with similar image contrast as in the non-interleaved images. A total of 1076 lesions were identified in all patients on the combined SW-FLAIR image, of which 968 lesions (90%) had visible penetrating veins. Lesion-to-vein contrast ratio was 32.7 ± 17.9 (mean ± standard deviation) for the interleaved sequence compared to 28.1 ± 13.7 using the separate acquisitions (P<0.001). Conclusion The feasibility of interleaved acquisition of susceptibility-weighted and FLAIR images was demonstrated. This sequence provides self-registered images and facilitates the visualization of veins in brain lesions.
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Affiliation(s)
- Refaat E. Gabr
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX
| | - Amol S. Pednekar
- Philips Healthcare, Cleveland, OH
- Texas Children’s Hospital, Houston, TX
| | - Arash Kamali
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX
| | - John A Lincoln
- Department of Neurology, University of Texas Health Science Center at Houston, Houston, TX
| | - Flavia M. Nelson
- Department of Neurology, University of Texas Health Science Center at Houston, Houston, TX
| | - Jerry S. Wolinsky
- Department of Neurology, University of Texas Health Science Center at Houston, Houston, TX
| | - Ponnada A. Narayana
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX
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17
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Walsh AJ, Sun H, Emery DJ, Wilman AH. Hematocrit Measurement with R2* and Quantitative Susceptibility Mapping in Postmortem Brain. AJNR Am J Neuroradiol 2018; 39:1260-1266. [PMID: 29794234 DOI: 10.3174/ajnr.a5677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 04/01/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE Noninvasive venous oxygenation quantification with MR imaging will improve the neurophysiologic investigation and the understanding of the pathophysiology in neurologic diseases. Available MR imaging methods are limited by sensitivity to flow and often require assumptions of the hematocrit level. In situ postmortem imaging enables evaluation of methods in a fully deoxygenated environment without flow artifacts, allowing direct calculation of hematocrit. This study compares 2 venous oxygenation quantification methods in in situ postmortem subjects. MATERIALS AND METHODS Transverse relaxation (R2*) mapping and quantitative susceptibility mapping were performed on a whole-body 4.7T MR imaging system. Intravenous measurements in major draining intracranial veins were compared between the 2 methods in 3 postmortem subjects. The quantitative susceptibility mapping technique was also applied in 10 healthy control subjects and compared with reference venous oxygenation values. RESULTS In 2 early postmortem subjects, R2* mapping and quantitative susceptibility mapping measurements within intracranial veins had a significant and strong correlation (R2 = 0.805, P = .004 and R2 = 0.836, P = .02). Higher R2* and susceptibility values were consistently demonstrated within gravitationally dependent venous segments during the early postmortem period. Hematocrit ranged from 0.102 to 0.580 in postmortem subjects, with R2* and susceptibility as large as 291 seconds-1 and 1.75 ppm, respectively. CONCLUSIONS Measurements of R2* and quantitative susceptibility mapping within large intracranial draining veins have a high correlation in early postmortem subjects. This study supports the use of quantitative susceptibility mapping for evaluation of in vivo venous oxygenation and postmortem hematocrit concentrations.
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Affiliation(s)
- A J Walsh
- From the Departments of Biomedical Engineering (A.J.W., H.S., A.H.W.)
- Radiology and Diagnostic Imaging (A.J.W., D.J.E.), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - H Sun
- From the Departments of Biomedical Engineering (A.J.W., H.S., A.H.W.)
| | - D J Emery
- Radiology and Diagnostic Imaging (A.J.W., D.J.E.), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - A H Wilman
- From the Departments of Biomedical Engineering (A.J.W., H.S., A.H.W.)
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18
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Hosseini Z, Matusinec J, Rudko DA, Liu J, Kwan BYM, Salehi F, Sharma M, Kremenchutzky M, Menon RS, Drangova M. Morphology-Specific Discrimination between MS White Matter Lesions and Benign White Matter Hyperintensities Using Ultra-High-Field MRI. AJNR Am J Neuroradiol 2018; 39:1473-1479. [PMID: 29930096 DOI: 10.3174/ajnr.a5705] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/05/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Recently published North American Imaging in Multiple Sclerosis guidelines call for derivation of a specific radiologic definition of MS WM lesions and mimics. The purpose of this study was to use SWI and magnetization-prepared FLAIR images for sensitive differentiation of MS from benign WM lesions using the morphologic characteristics of WM lesions. MATERIALS AND METHODS Seventeen patients with relapsing-remitting MS and 18 healthy control subjects were enrolled retrospectively. For each subject, FLAIR and multiecho gradient-echo images were acquired using 7T MR imaging. Optimized postprocessing was used to generate single-slice SWI of cerebral veins. SWI/FLAIR images were registered, and 3 trained readers performed lesion assessment. Morphology, location of lesions, and the time required for assessment were recorded. Analyses were performed on 3 different pools: 1) lesions of >3 mm, 2) nonconfluent lesions of >3 mm, and 3) nonconfluent lesions of >3 mm with no or a single central vein. RESULTS The SWI/FLAIR acquisition and processing protocol enabled effective assessment of central veins and hypointense rims in WM lesions. Assessment of nonconfluent lesions with ≥1 central vein enabled the most specific and sensitive differentiation of patients with MS from controls. A threshold of 67% perivenous WM lesions separated patients with MS from controls with a sensitivity of 94% and specificity of 100%. Lesion assessment took an average of 12 minutes 10 seconds and 4 minutes 33 seconds for patients with MS and control subjects, respectively. CONCLUSIONS Nonconfluent lesions of >3 mm with ≥1 central vein were the most sensitive and specific differentiators between patients with MS and control subjects.
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Affiliation(s)
- Z Hosseini
- From the Biomedical Engineering Graduate Program (Z.H., R.S.M., M.D.).,Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute
| | | | - D A Rudko
- Department of Neurology and Neurosurgery (D.A.R.), McConnell Brain Imaging Centre, Montreal Neurological Institute.,Department of Biomedical Engineering (D.A.R.), McGill University, Montreal, Quebec, Canada
| | - J Liu
- Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute
| | | | - F Salehi
- Medical Imaging (B.Y.M.K., F.S., M.S.)
| | - M Sharma
- Medical Imaging (B.Y.M.K., F.S., M.S.).,Department of Clinical Neurological Sciences (M.S., M.K.), Western University and London Health Sciences Centre, London, Ontario, Canada
| | - M Kremenchutzky
- Department of Clinical Neurological Sciences (M.S., M.K.), Western University and London Health Sciences Centre, London, Ontario, Canada
| | - R S Menon
- From the Biomedical Engineering Graduate Program (Z.H., R.S.M., M.D.).,Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute.,Medical Biophysics (R.S.M., M.D.), Schulich School of Medicine and Dentistry; Western University, London, Ontario, Canada
| | - M Drangova
- From the Biomedical Engineering Graduate Program (Z.H., R.S.M., M.D.) .,Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute.,Medical Biophysics (R.S.M., M.D.), Schulich School of Medicine and Dentistry; Western University, London, Ontario, Canada
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19
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Absinta M, Sati P, Fechner A, Schindler MK, Nair G, Reich DS. Identification of Chronic Active Multiple Sclerosis Lesions on 3T MRI. AJNR Am J Neuroradiol 2018; 39:1233-1238. [PMID: 29724768 DOI: 10.3174/ajnr.a5660] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/13/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND PURPOSE MR imaging-pathologic studies have reported that paramagnetic rims on 7T susceptibility-based MR imaging identify, in vivo, the subset of MS lesions with compartmentalized inflammation at the lesion edge and associated remyelination failure. Here, we assessed the reliability of detecting these rims on high-resolution 3T phase images. MATERIALS AND METHODS High-resolution T2* and phase MR imaging was collected in 20 patients with MS at 3T (3D segmented EPI, 0.65 mm3) and 7T (2D gradient-echo, 0.2 × 0.2 × 1 mm) MR imaging. In each case, 5 discrete chronic (nonenhancing) MS lesions were selected on T2 FLAIR images for rim evaluation. Five raters experienced in MS imaging contributed to the rim assessment, of whom 3 worked independently on 3T data, and 2, on 7T data. Consensus agreement was reached for both 3T and 7T rim evaluations. Discrepancies between 3T and 7T were discussed, and consensus was reached. RESULTS Phase rims were seen in 34 lesions at 7T and in 36 lesions at 3T by consensus. Inter- and intrarater reliability were "substantial/good" both at 3T and 7T analysis (Cohen κ, >0.71). Based on consensus agreement, the reliability of rim visualization at 3T versus 7T was 0.78 (κ) with a pair-wise agreement of 90%. More lesions were judged to be false-positive or false-negative at 3T than at 7T. CONCLUSIONS Nearly all 7T paramagnetic rims can also be seen at 3T. Imaging at 3T opens the possibility of implementing paramagnetic rims as an outcome measure in multicenter, MR imaging-based clinical trials aimed at treating perilesional persistent inflammation and its potential effects on remyelination.
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Affiliation(s)
- M Absinta
- From the Translational Neuroradiology Section (M.A., P.S., A.F., M.K.S., G.N., D.S.R.), Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - P Sati
- From the Translational Neuroradiology Section (M.A., P.S., A.F., M.K.S., G.N., D.S.R.), Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - A Fechner
- From the Translational Neuroradiology Section (M.A., P.S., A.F., M.K.S., G.N., D.S.R.), Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland.,Department of Radiology (A.F.), Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
| | - M K Schindler
- From the Translational Neuroradiology Section (M.A., P.S., A.F., M.K.S., G.N., D.S.R.), Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - G Nair
- From the Translational Neuroradiology Section (M.A., P.S., A.F., M.K.S., G.N., D.S.R.), Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - D S Reich
- From the Translational Neuroradiology Section (M.A., P.S., A.F., M.K.S., G.N., D.S.R.), Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
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20
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Abstract
Since its technical development in the early 1980s, magnetic resonance imaging (MRI) has quickly been adopted as an essential tool in supporting the diagnosis, longitudinal monitoring, evaluation of therapeutic response, and scientific investigations in multiple sclerosis (MS). The clinical usage of MRI has increased in parallel with technical innovations in the technique itself; the widespread adoption of clinically routine MRI at 1.5T has allowed sensitive qualitative and quantitative assessments of macroscopic central nervous system (CNS) inflammatory demyelinating lesions and tissue atrophy. However, conventional MRI lesion measures lack specificity for the underlying MS pathology and only weakly correlate with clinical status. Higher field strength units and newer, advanced MRI techniques offer increased sensitivity and specificity in the detection of disease activity and disease severity. This review summarizes the current status and future prospects regarding the role of MRI in the characterization of MS-related brain and spinal cord involvement.
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Affiliation(s)
- Christopher C Hemond
- Laboratory for Neuroimaging Research, Partners Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases, Departments of Neurology and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Rohit Bakshi
- Laboratory for Neuroimaging Research, Partners Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases, Departments of Neurology and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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21
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Trattnig S, Springer E, Bogner W, Hangel G, Strasser B, Dymerska B, Cardoso PL, Robinson SD. Key clinical benefits of neuroimaging at 7T. Neuroimage 2018; 168:477-489. [PMID: 27851995 PMCID: PMC5832016 DOI: 10.1016/j.neuroimage.2016.11.031] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/06/2016] [Accepted: 11/12/2016] [Indexed: 01/15/2023] Open
Abstract
The growing interest in ultra-high field MRI, with more than 35.000 MR examinations already performed at 7T, is related to improved clinical results with regard to morphological as well as functional and metabolic capabilities. Since the signal-to-noise ratio increases with the field strength of the MR scanner, the most evident application at 7T is to gain higher spatial resolution in the brain compared to 3T. Of specific clinical interest for neuro applications is the cerebral cortex at 7T, for the detection of changes in cortical structure, like the visualization of cortical microinfarcts and cortical plaques in Multiple Sclerosis. In imaging of the hippocampus, even subfields of the internal hippocampal anatomy and pathology may be visualized with excellent spatial resolution. Using Susceptibility Weighted Imaging, the plaque-vessel relationship and iron accumulations in Multiple Sclerosis can be visualized, which may provide a prognostic factor of disease. Vascular imaging is a highly promising field for 7T which is dealt with in a separate dedicated article in this special issue. The static and dynamic blood oxygenation level-dependent contrast also increases with the field strength, which significantly improves the accuracy of pre-surgical evaluation of vital brain areas before tumor removal. Improvement in acquisition and hardware technology have also resulted in an increasing number of MR spectroscopic imaging studies in patients at 7T. More recent parallel imaging and short-TR acquisition approaches have overcome the limitations of scan time and spatial resolution, thereby allowing imaging matrix sizes of up to 128×128. The benefits of these acquisition approaches for investigation of brain tumors and Multiple Sclerosis have been shown recently. Together, these possibilities demonstrate the feasibility and advantages of conducting routine diagnostic imaging and clinical research at 7T.
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Affiliation(s)
- Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MRI, Vienna, Austria.
| | - Elisabeth Springer
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MRI, Vienna, Austria.
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Gilbert Hangel
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Bernhard Strasser
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Barbara Dymerska
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Pedro Lima Cardoso
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Simon Daniel Robinson
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
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22
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Eisele P, Szabo K, Ebert A, Brueck W, Platten M, Gass A. Spatiotemporal evolution of venous narrowing in acute MS lesions. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2018; 5:e440. [PMID: 29359176 PMCID: PMC5773855 DOI: 10.1212/nxi.0000000000000440] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/06/2017] [Indexed: 01/14/2023]
Abstract
Objective To investigate the spatiotemporal evolution of venous narrowing in newly developing MS lesions in a longitudinal MRI study including susceptibility-weighted images (SWIs). Methods We retrospectively investigated serial MR examinations of 18 patients with MS acquired on a 3T MRI system including SWI for acute contrast-enhancing lesions with at least 1 MRI examination before contrast enhancement. The mean diameter of veins at the time point of contrast enhancement was compared with the mean diameter of veins before and after contrast enhancement. Results A total of 40 acute contrast-enhancing lesions with a corresponding intralesional central vein were included in the study. The mean diameter of intralesional veins at the time of contrast enhancement (0.80 ± 0.12 mm) was smaller than that at before (1.16 ± 0.19 mm) and after contrast enhancement (1.07 ± 0.15 mm; p < 0.001 for all comparisons). Conclusions Our findings contribute to the increasing database of plaque development and evolution. The smaller diameter of intralesional veins on SWI at the time of blood-brain barrier breakdown may reflect morphologic changes because of perivascular inflammation and/or decreased levels of deoxygenated hemoglobin.
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Affiliation(s)
- Philipp Eisele
- Department of Neurology (P.E., K.S., A.E., M.P., A.G.), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim; and Institute for Neuropathology (W.B.), Universitätsmedizin Göttingen, Germany
| | - Kristina Szabo
- Department of Neurology (P.E., K.S., A.E., M.P., A.G.), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim; and Institute for Neuropathology (W.B.), Universitätsmedizin Göttingen, Germany
| | - Anne Ebert
- Department of Neurology (P.E., K.S., A.E., M.P., A.G.), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim; and Institute for Neuropathology (W.B.), Universitätsmedizin Göttingen, Germany
| | - Wolfgang Brueck
- Department of Neurology (P.E., K.S., A.E., M.P., A.G.), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim; and Institute for Neuropathology (W.B.), Universitätsmedizin Göttingen, Germany
| | - Michael Platten
- Department of Neurology (P.E., K.S., A.E., M.P., A.G.), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim; and Institute for Neuropathology (W.B.), Universitätsmedizin Göttingen, Germany
| | - Achim Gass
- Department of Neurology (P.E., K.S., A.E., M.P., A.G.), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim; and Institute for Neuropathology (W.B.), Universitätsmedizin Göttingen, Germany
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Abstract
PURPOSE OF REVIEW Gadolinium-enhancement depicts blood-brain barrier disruption associated with new inflammatory MRI lesions in multiple sclerosis (MS) and is widely used for diagnosis and therapeutic monitoring. However, earlier and more specific markers of inflammation are urgently needed. RECENT FINDINGS Susceptibility-weighted images demonstrate the importance of the central vein in the formation of MS lesions. Perfusion weighted imaging techniques can show focal and diffuse low-grade inflammatory changes not visible on conventional MRI. Leptomeningeal enhancement could be part of the aetiology of subpial cortical MS lesions. Ultrasmall superparamagnetic particles of iron oxide can identify neuroinflammatory changes in addition to gadolinium enhancement and as such identify different types and phases of MS lesions. 18kD-translocator protein PET tracers identify activated microglia and an increase in TSPO uptake in both MS lesions and normal appearing brain tissue is related to disease severity and progression. A range of novel tracers for microglia activation is under development as well as radioligands that can label therapeutic drugs. SUMMARY Novel MRI and PET techniques improve in-vivo visualization and quantification of the pleomorphic aspects of neuroinflammation, providing us with a unique insight in its pathogenesis, clinical relevance, and therapy responsiveness in MS.
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Springer E, Dymerska B, Cardoso PL, Robinson SD, Weisstanner C, Wiest R, Schmitt B, Trattnig S. Comparison of Routine Brain Imaging at 3 T and 7 T. Invest Radiol 2017; 51:469-82. [PMID: 26863580 DOI: 10.1097/rli.0000000000000256] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of this study was to compare quantitative and semiquantitative parameters (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], image quality, diagnostic confidence) from a standard brain magnetic resonance imaging examination encompassing common neurological disorders such as demyelinating disease, gliomas, cerebrovascular disease, and epilepsy, with comparable sequence protocols and acquisition times at 3 T and at 7 T. MATERIALS AND METHODS Ten healthy volunteers and 4 subgroups of 40 patients in total underwent comparable magnetic resonance protocols with standard diffusion-weighted imaging, 2D and 3D turbo spin echo, 2D and 3D gradient echo and susceptibility-weighted imaging of the brain (10 sequences) at 3 T and 7 T. The subgroups comprised patients with either lesional (n = 5) or nonlesional (n = 4) epilepsy, intracerebral tumors (n = 11), demyelinating disease (n = 11) (relapsing-remitting multiple sclerosis [MS, n = 9], secondary progressive MS [n = 1], demyelinating disease not further specified [n = 1]), or chronic cerebrovascular disorders [n = 9]). For quantitative analysis, SNR and CNR were determined. For a semiquantitative assessment of the diagnostic confidence, a 10-point scale diagnostic confidence score (DCS) was applied. Two experienced radiologists with additional qualification in neuroradiology independently assessed, blinded to the field strength, 3 pathology-specific imaging criteria in each of the 4 disease groups and rated their diagnostic confidence. The overall image quality was semiquantitatively assessed using a 4-point scale taking into account whether diagnostic decision making was hampered by artifacts or not. RESULTS Without correction for spatial resolution, SNR was higher at 3 T except in the T2 SPACE 3D, DWI single shot, and DIR SPACE 3D sequences. The SNR corrected by the ratio of 3 T/7 T voxel sizes was higher at 7 T than at 3 T in 10 of 11 sequences (all except for T1 MP2RAGE 3D).In CNR, there was a wide variation between sequences and patient cohorts, but average CNR values were broadly similar at 3 T and 7 T.DCS values for all 4 pathologic entities were higher at 7 T than at 3 T. The DCS was significantly higher at 7 T for diagnosis and exclusion of cortical lesions in vascular disease. A tendency to higher DCS at 7 T for cortical lesions in MS was observed, and for the depiction of a central vein and iron deposits within MS lesions. Despite motion artifacts, DCS values were higher at 7 T for the diagnosis and exclusion of hippocampal sclerosis in mesial temporal lobe epilepsy (improved detection of the hippocampal subunits). Interrater agreement was 69.7% at 3 T and 93.3% at 7 T. There was no significant difference in the overall image quality score between 3 T and 7 T taking into account whether diagnostic decision making was hampered by artifacts or not. CONCLUSIONS Ultra-high-field magnetic resonance imaging at 7 T compared with 3 T yielded an improved diagnostic confidence in the most frequently encountered neurologic disorders. Higher spatial resolution and contrast were identified as the main contributory factors.
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Affiliation(s)
- Elisabeth Springer
- From the *High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria; †Support Center of Advanced Neuroimaging, University Institute for Diagnostic and Interventional Neuroradiology, University Hospital Bern and Inselspital, University of Bern, Bern, Switzerland; ‡Siemens Healthcare Pty Ltd Australia, Imaging and Therapy Systems, Magnetic Resonance, Macquarie Park, New South Wales, Australia; §Siemens Healthcare, Erlangen, Germany; and ∥CD Laboratory for Molecular Clinical MR Imaging, Vienna, Austria
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Understanding a role for hypoxia in lesion formation and location in the deep and periventricular white matter in small vessel disease and multiple sclerosis. Clin Sci (Lond) 2017; 131:2503-2524. [PMID: 29026001 DOI: 10.1042/cs20170981] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 08/01/2017] [Accepted: 08/15/2017] [Indexed: 12/28/2022]
Abstract
The deep and periventricular white matter is preferentially affected in several neurological disorders, including cerebral small vessel disease (SVD) and multiple sclerosis (MS), suggesting that common pathogenic mechanisms may be involved in this injury. Here we consider the potential pathogenic role of tissue hypoxia in lesion development, arising partly from the vascular anatomy of the affected white matter. Specifically, these regions are supplied by a sparse vasculature fed by long, narrow end arteries/arterioles that are vulnerable to oxygen desaturation if perfusion is reduced (as in SVD, MS and diabetes) or if the surrounding tissue is hypoxic (as in MS, at least). The oxygen crisis is exacerbated by a local preponderance of veins, as these can become highly desaturated 'sinks' for oxygen that deplete it from surrounding tissues. Additional haemodynamic deficiencies, including sluggish flow and impaired vasomotor reactivity and vessel compliance, further exacerbate oxygen insufficiency. The cells most vulnerable to hypoxic damage, including oligodendrocytes, die first, resulting in demyelination. Indeed, in preclinical models, demyelination is prevented if adequate oxygenation is maintained by raising inspired oxygen concentrations. In agreement with this interpretation, there is a predilection of lesions for the anterior and occipital horns of the lateral ventricles, namely regions located at arterial watersheds, or border zones, known to be especially susceptible to hypoperfusion and hypoxia. Finally, mitochondrial dysfunction due to genetic causes, as occurs in leucodystrophies or due to free radical damage, as occurs in MS, will compound any energy insufficiency resulting from hypoxia. Viewing lesion formation from the standpoint of tissue oxygenation not only reveals that lesion distribution is partly predictable, but may also inform new therapeutic strategies.
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Rogers DM, Peckham ME, Shah LM, Wiggins RH. Association of Developmental Venous Anomalies with Demyelinating Lesions in Patients with Multiple Sclerosis. AJNR Am J Neuroradiol 2017; 39:97-101. [PMID: 28912286 DOI: 10.3174/ajnr.a5374] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 07/12/2017] [Indexed: 11/07/2022]
Abstract
We present 5 cases of demyelination in patients diagnosed with multiple sclerosis that are closely associated with a developmental venous anomaly. Although the presence of a central vein is a known phenomenon with multiple sclerosis plaques, demyelination occurring around developmental venous anomalies is an underreported phenomenon. Tumefactive demyelination can cause a diagnostic dilemma because of its overlapping imaging findings with central nervous system neoplasm. The relationship of a tumefactive plaque with a central vein can be diagnostically useful, and we suggest that if such a lesion is closely associated with a developmental venous anomaly, an inflammatory or demyelinating etiology should be a leading consideration.
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Affiliation(s)
- D M Rogers
- From the Department of Radiology and Imaging Science, University of Utah Medical Center, Salt Lake City, Utah.
| | - M E Peckham
- From the Department of Radiology and Imaging Science, University of Utah Medical Center, Salt Lake City, Utah
| | - L M Shah
- From the Department of Radiology and Imaging Science, University of Utah Medical Center, Salt Lake City, Utah
| | - R H Wiggins
- From the Department of Radiology and Imaging Science, University of Utah Medical Center, Salt Lake City, Utah
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Abstract
Magnetic resonance imaging (MRI) plays a key role in the investigation of cerebrovascular diseases. Compared with computed tomography (CT) and digital subtraction angiography (DSA), its advantages in diagnosing cerebrovascular pathology include its superior tissue contrast, its ability to visualize blood vessels without the use of a contrast agent, and its use of magnetic fields and radiofrequency pulses instead of ionizing radiation. In recent years, ultrahigh field MRI at 7 tesla (7 T) has shown promise in the diagnosis of many cerebrovascular diseases. The increased signal-to-noise ratio (SNR; 2.3x and 4.7x increase compared with 3 and 1.5 T, respectively) and contrast-to-noise ratio (CNR) at this higher field strength can be exploited to obtain a higher spatial resolution and higher lesion conspicuousness, enabling assessment of smaller brain structures and lesions. Cerebrovascular diseases can be assessed at different tissue levels; for instance, changes of the arteries feeding the brain can be visualized to determine the cause of ischemic stroke, regional changes in brain perfusion can be mapped to predict outcome after revascularization, and tissue damage, including old and recent ischemic infarcts, can be evaluated as a marker of ischemic burden. For the purpose of this review, we will discriminate 3 levels of assessment of cerebrovascular diseases using MRI: Pipes, Perfusion, and Parenchyma (3 Ps). The term Pipes refers to the brain-feeding arteries from the heart and aortic arch, upwards to the carotid arteries, vertebral arteries, circle of Willis, and smaller intracranial arterial branches. Perfusion is the amount of blood arriving at the brain tissue level, and includes the vascular reserve and perfusion territories. Parenchyma refers to the acute and chronic burden of brain tissue damage, which includes larger infarcts, smaller microinfarcts, and small vessel disease manifestations such as white matter lesions, lacunar infarcts, and microbleeds. In this review, we will describe the key developments in the last decade of 7-T MRI of cerebrovascular diseases, subdivided for these 3 levels of assessment.
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Dal-Bianco A, Grabner G, Kronnerwetter C, Weber M, Höftberger R, Berger T, Auff E, Leutmezer F, Trattnig S, Lassmann H, Bagnato F, Hametner S. Slow expansion of multiple sclerosis iron rim lesions: pathology and 7 T magnetic resonance imaging. Acta Neuropathol 2017; 133:25-42. [PMID: 27796537 PMCID: PMC5209400 DOI: 10.1007/s00401-016-1636-z] [Citation(s) in RCA: 271] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 12/14/2022]
Abstract
In multiple sclerosis (MS), iron accumulates inside activated microglia/macrophages at edges of some chronic demyelinated lesions, forming rims. In susceptibility-based magnetic resonance imaging at 7 T, iron-laden microglia/macrophages induce a rim of decreased signal at lesion edges and have been associated with slowly expanding lesions. We aimed to determine (1) what lesion types and stages are associated with iron accumulation at their edges, (2) what cells at the lesion edges accumulate iron and what is their activation status, (3) how reliably can iron accumulation at the lesion edge be detected by 7 T magnetic resonance imaging (MRI), and (4) if lesions with rims enlarge over time in vivo, when compared to lesions without rims. Double-hemispheric brain sections of 28 MS cases were stained for iron, myelin, and microglia/macrophages. Prior to histology, 4 of these 28 cases were imaged at 7 T using post-mortem susceptibility-weighted imaging. In vivo, seven MS patients underwent annual neurological examinations and 7 T MRI for 3.5 years, using a fluid attenuated inversion recovery/susceptibility-weighted imaging fusion sequence. Pathologically, we found iron rims around slowly expanding and some inactive lesions but hardly around remyelinated shadow plaques. Iron in rims was mainly present in microglia/macrophages with a pro-inflammatory activation status, but only very rarely in astrocytes. Histological validation of post-mortem susceptibility-weighted imaging revealed a quantitative threshold of iron-laden microglia when a rim was visible. Slowly expanding lesions significantly exceeded this threshold, when compared with inactive lesions (p = 0.003). We show for the first time that rim lesions significantly expanded in vivo after 3.5 years, compared to lesions without rims (p = 0.003). Thus, slow expansion of MS lesions with rims, which reflects chronic lesion activity, may, in the future, become an MRI marker for disease activity in MS.
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Sati P, Oh J, Constable RT, Evangelou N, Guttmann CRG, Henry RG, Klawiter EC, Mainero C, Massacesi L, McFarland H, Nelson F, Ontaneda D, Rauscher A, Rooney WD, Samaraweera APR, Shinohara RT, Sobel RA, Solomon AJ, Treaba CA, Wuerfel J, Zivadinov R, Sicotte NL, Pelletier D, Reich DS. The central vein sign and its clinical evaluation for the diagnosis of multiple sclerosis: a consensus statement from the North American Imaging in Multiple Sclerosis Cooperative. Nat Rev Neurol 2016; 12:714-722. [DOI: 10.1038/nrneurol.2016.166] [Citation(s) in RCA: 194] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Absinta M, Sati P, Schindler M, Leibovitch EC, Ohayon J, Wu T, Meani A, Filippi M, Jacobson S, Cortese ICM, Reich DS. Persistent 7-tesla phase rim predicts poor outcome in new multiple sclerosis patient lesions. J Clin Invest 2016; 126:2597-609. [PMID: 27270171 DOI: 10.1172/jci86198] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/12/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND In some active multiple sclerosis (MS) lesions, a strong immune reaction at the lesion edge may contain growth and thereby isolate the lesion from the surrounding parenchyma. Our previous studies suggest that this process involves opening of the blood-brain barrier in capillaries at the lesion edge, seen on MRI as centripetal contrast enhancement and a colocalized phase rim. We hypothesized that using these features to characterize early lesion evolution will allow in vivo tracking of tissue degeneration and/or repair, thus improving the evaluation of potential therapies for chronic active lesions. METHODS Centripetally and centrifugally enhancing lesions were studied in 17 patients with MS using 7-tesla MRI. High-resolution, susceptibility-weighted, T1-weighted (before/after gadolinium), and dynamic contrast-enhanced scans were acquired at baseline and months 1, 3, 6, and 12. For each lesion, time evolution of the phase rim, lesion volume, and T1 hypointensity were assessed. In autopsies of 3 progressive MS cases, the histopathology of the phase rim was determined. RESULTS In centripetal lesions, a phase rim colocalized with initial contrast enhancement. In 12 of 22, this phase rim persisted after enhancement resolved. Compared with centripetal lesions with transient rim, those with persistent rim had less volume shrinkage and became more T1 hypointense between months 3 and 12. No centrifugal lesions developed phase rims at any time point. Pathologically, persistent rims corresponded to an iron-laden inflammatory myeloid cell population at the edge of chronic demyelinated lesions. CONCLUSION In early lesion evolution, a persistent phase rim in lesions that shrink least and become more T1 hypointense over time suggests that the rim might mark failure of early lesion repair and/or irreversible tissue damage. In later stages of MS, phase rim lesions continue to smolder, exerting detrimental effects on affected brain tissue. TRIAL REGISTRATION NCT00001248. FUNDING The Intramural Research Program of NINDS supported this study.
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The effect of venous anatomy on the morphology of multiple sclerosis lesions: a susceptibility-weighted imaging study. Clin Radiol 2016; 71:418-26. [DOI: 10.1016/j.crad.2016.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/14/2015] [Accepted: 02/05/2016] [Indexed: 11/20/2022]
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Abstract
Over the past few decades, MRI-based visualization of demyelinated CNS lesions has become pivotal to the diagnosis and monitoring of multiple sclerosis (MS). In this Review, we outline current efforts to correlate imaging findings with the pathology of lesion development in MS, and the pitfalls that are being encountered in this research. Multimodal imaging at high and ultra-high magnetic field strengths is yielding biologically relevant insights into the pathophysiology of blood-brain barrier dynamics and both active and chronic inflammation, as well as mechanisms of lesion healing and remyelination. Here, we parallel the results in humans with advances in imaging of a primate model of MS - experimental autoimmune encephalomyelitis (EAE) in the common marmoset - in which demyelinated lesions resemble their human counterparts far more closely than do EAE lesions in the rodent. This approach holds promise for the identification of innovative biological markers, and for next-generation clinical trials that will focus more on tissue protection and repair.
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Spring cleaning: time to rethink imaging research lines in MS? J Neurol 2016; 263:1893-902. [PMID: 26886204 DOI: 10.1007/s00415-016-8060-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 02/03/2016] [Accepted: 02/03/2016] [Indexed: 12/15/2022]
Abstract
Together with recently advanced MRI technological capability, new needs and updated questions are emerging in imaging research in multiple sclerosis (MS), especially with respect to the identification of novel in vivo biomarkers of MS-relevant pathological processes. Expected benefits will involve approaches to diagnosis and clinical classification. In detail, three main points of discussion are addressed in this review: (1) new imaging biomarkers (centrifugal/centripetal lesion enhancement, central vein, paramagnetic rims at the lesion edge, subpial cortical demyelination); (2) thinking about high-resolution MR from a pathological perspective (from postmortem to in vivo staging); and (3) the clinical utility of quantitative MRI. In this context, research efforts should increasingly be focused on the direct in vivo visualization of "hidden" inflammation, beyond what can be detected with conventional gadolinium-based methods, as well as remyelination and repair, since these are likely to represent critical pathological processes and potential therapeutic targets. Concluding remarks concern the limitations, challenges, and ultimately clinical role of non-conventional MRI techniques.
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