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Purpose: We investigated the correlation, reproducibility, and effect of white matter fiber orientation for three myelin‐sensitive MRI techniques: magnetization transfer ratio (MTR), inhomogeneous magnetization transfer ratio (ihMTR), and gradient and spin echo–derived myelin water fraction (MWF). Methods: We measured the three metrics in 17 white and three deep grey matter regions in 17 healthy adults at 3 T. Results: We found a strong correlation between ihMTR and MTR (r = 0.70, p < 0.001) and ihMTR and MWF (r = 0.79, p < 0.001), and a weaker correlation between MTR and MWF (r = 0.54, p < 0.001). The dynamic range in white matter was greatest for MWF (2.0%–27.5%), followed by MTR (14.4%–23.2%) and then ihMTR (1.2%–5.4%). The average scan–rescan coefficient of variation for white matter regions was 0.6% MTR, 0.3% ihMTR, and 0.7% MWF in metric units; however, when adjusted by the dynamic range, these became 6.3%, 6.1% and 2.8%, respectively. All three metrics varied with fiber direction: MWF and ihMTR were lower in white matter fibers perpendicular to B0 by 6% and 1%, respectively, compared with those parallel, whereas MTR was lower by 0.5% at about 40°, with the highest values at 90°. However, separating the apparent orientation dependence by white matter region revealed large dissimilarities in the trends, suggesting that real differences in myelination between regions are confounding the apparent orientation dependence measured using this method. Conclusion: The strong correlation between ihMTR and MWF suggests that these techniques are measuring the same myelination; however, the larger dynamic range of MWF may provide more power to detect small differences in myelin. [ABSTRACT FROM AUTHOR]

Objective: The study objective was to investigate the predictive value of functional connectivity changes induced by acute repetitive transcranial magnetic stimulation (rTMS) for clinical response in treatment-resistant depression.Methods: Cross-sectional changes in functional connectivity induced by a single concurrent rTMS-fMRI session were assessed in 38 outpatients with treatment-resistant depression (26 of them female; mean age, 41.87 years) who subsequently underwent a 4-week course of rTMS. rTMS was delivered at 1 Hz over the right dorsolateral prefrontal cortex. Acute rTMS-induced functional connectivity changes were computed and subjected to connectome-based predictive modeling to test their association with changes in score on the Montgomery-Åsberg Depression Rating Scale (MADRS) after rTMS treatment.Results: TMS-fMRI induced widespread, acute, and transient alterations in functional connectivity. The rTMS-induced connectivity changes predicted about 30% of the variance of improvement in the MADRS score. The most robust predictive associations involved connections between prefrontal regions and motor, parietal, and insular cortices and between bilateral regions of the thalamus.Conclusions: Acute rTMS-induced connectivity changes in patients with treatment-resistant depression may index macro-level neuroplasticity, relevant to interindividual variability in rTMS treatment response. Large-scale network phenomena occurring during rTMS might be used to inform prospective clinical trials. [ABSTRACT FROM AUTHOR]

Purpose: To combine metabolite cycling with J‐difference editing (MC MEGA) to allow for prospective frequency correction at each transient without additional acquisitions and compare it to water‐suppressed MEGA‐PRESS (WS MEGA) editing with intermittent prospective frequency correction. Methods: Macromolecule‐suppressed gamma aminobutyric acid (GABA)‐edited experiments were performed in a phantom and in the occipital lobe (OCC) (n = 12) and medial prefrontal cortex (mPFC) (n = 8) of the human brain. Water frequency consistency and average offset over acquisition time were compared. GABA multiplet patterns, signal intensities, and choline subtraction artifacts were evaluated. In vivo GABA concentrations were compared and related to frequency offset in the OCC. Results: MC MEGA was more stable with 21% and 32% smaller water frequency SDs in the OCC and mPFC, respectively. MC MEGA also had 39% and 40% smaller average frequency offsets in the OCC and mPFC, respectively. Phantom GABA multiplet patterns and signal intensities were similar. In vivo GABA concentrations were smaller in MC MEGA than in WS MEGA, with median (interquartile range) of 2.52 (0.27) and 2.29 (0.19) institutional units (i.u.), respectively in the OCC scans without prior DTI, and 0.99 (0.3) and 1.72 (0.5), respectively in the mPFC. OCC WS MEGA GABA concentrations, but not MC MEGA GABA concentrations were moderately correlated with frequency offset. mPFC WS MEGA spectra contained significantly more subtraction artifacts than MC MEGA spectra. Conclusion: MC MEGA is feasible and allows for prospective frequency correction at every transient. MC MEGA GABA concentrations were not biased by frequency offsets and contained less subtraction artifacts compared to WS MEGA. [ABSTRACT FROM AUTHOR]

Purpose: Myelin water imaging (MWI) provides a valuable biomarker for myelin, but clinical application has been restricted by long acquisition times. Accelerating the standard multi‐echo T2 acquisition with gradient echoes (GRASE) or by 2D multi‐slice data collection results in image blurring, contrast changes, and other issues. Compressed sensing (CS) can vastly accelerate conventional MRI. In this work, we assessed the use of CS for in vivo human MWI, using a 3D multi spin‐echo sequence. Methods: We implemented multi‐echo T2 relaxation imaging with compressed sensing (METRICS) and METRICS with partial Fourier acceleration (METRICS‐PF). Scan‐rescan data were acquired from 12 healthy controls for assessment of repeatability. MWI data were acquired for METRICS in 9 m:58 s and for METRICS‐PF in 7 m:25 s, both with 1.5 × 2 × 3 mm3 voxels, 56 echoes, 7 ms ΔTE, and 240 × 240 × 170 mm3 FOV. METRICS was compared with a novel multi‐echo spin‐echo gold‐standard (MSE‐GS) MWI acquisition, acquired for a single additional subject in 2 h:2 m:40 s. Results: METRICS/METRICS‐PF myelin water fraction had mean: repeatability coefficient 1.5/1.1, coefficient of variation 6.2/4.5%, and intra‐class correlation coefficient 0.79/0.84. Repeatability metrics comparing METRICS with METRICS‐PF were similar, and both sequences agreed with reference values from literature. METRICS images and quantitative maps showed excellent qualitative agreement with those of MSE‐GS. Conclusion: METRICS and METRICS‐PF provided highly repeatable MWI data without the inherent disadvantages of GRASE or 2D multi‐slice acquisition. CS acceleration allows MWI data to be acquired rapidly with larger FOV, higher estimated SNR, more isotropic voxels and more echoes than with previous techniques. The approach introduced here generalizes to any multi‐component T2 mapping application. [ABSTRACT FROM AUTHOR]

Background and Purpose: Acquiring and interpreting quantitative myelin-specific MRI data at an individual level is challenging because of technical difficulties and natural myelin variation in the population. To overcome these challenges, we used multiecho T2 myelin water imaging (MWI) to create T2 metric healthy population atlases that depict the mean and variation of myelin water fraction (MWF), and intra- and extracellular water mobility as described by geometric mean T2 (IEGMT2 ).Methods: Cervical cord MWI was performed at 3T on 20 healthy individuals (10M/10F, mean age: 36 years) and 3 relapsing remitting multiple sclerosis (RRMS) participants (1M/2F, age: 39/42/37 years). Anatomical data were collected for the purpose of image segmentation and registration. Atlases were created by coregistering and averaging T2 metrics from all controls. Voxel-wise z-score maps from 3 RRMS participants were produced to demonstrate the preliminary utility of the MWF and IEGMT2 atlases.Results: The average MWF atlas provides a representation of myelin in the spinal cord consistent with well-known spinal cord anatomical characteristics. The IEGMT2 atlas also depicted structural variations in the spinal cord. Z-score analysis illustrated distinct abnormalities in MWF and IEGMT2 in the 3 RRMS cases.Conclusions: Our findings highlight the potential for using a quantitative T2 relaxation metric atlas to visualize and detect pathology in spinal cord. Our MWF and IEGMT2 atlases (URL: https://sourceforge.net/projects/mwi-spinal-cord-atlases/) can serve as normative references in the cervical spinal cord for other studies. [ABSTRACT FROM AUTHOR]

Background and Purpose: Myelin water imaging (MWI) is a magnetic resonance imaging technique that quantifies myelin in-vivo. Although MWI has been extensively applied to study myelin-related diseases in groups, clinical use in individual patients is challenging mainly due to population heterogeneity. The purpose of this study was twofold: (1) create a normative brain myelin water atlas depicting the population mean and regional variability of myelin content; and (2) apply the myelin atlas to assess the degree of demyelination in individuals with multiple sclerosis (MS).Methods: 3T MWI was performed on 50 healthy adults (25 M/25 F, mean age 25 years [range 17-42 years]). The myelin water atlas was created by averaging coregistered myelin water fraction (MWF) maps from all healthy individuals. To illustrate the preliminary utility of the atlas, white matter (WM) regional MWF variations were evaluated and voxel-wise z-score maps (z < -1.96) from the MWI of three MS participants were produced to assess individually the degree of demyelination.Results: The myelin water atlas demonstrated significant MWF variation across control WM. No significant MWF differences were found between male and female healthy participants. MS z-score maps revealed diffuse regions of demyelination in the two participants with Expanded Disability Status Scale (EDSS) = 2.0 but not in the participant with EDSS = 0.Conclusions: The myelin water atlas can be used as a reference (URL: https://sourceforge.net/projects/myelin-water-atlas/) to demonstrate areas of demyelination in individual MS participants. Future studies will expand the atlas age range, account for education, and other variables that may affect myelination. [ABSTRACT FROM AUTHOR]

Background: Magnetic resonance spectroscopy quantitatively monitors biomarkers of neuron-myelin coupling (N-acetylaspartate (NAA)), and inflammation (total creatine (tCr), total choline (tCho), myo-inositol (mI)) in the brain. Objective: This study aims to investigate how ocrelizumab and interferon beta-1a differentially affects imaging biomarkers of neuronal-myelin coupling and inflammation in patients with relapsing multiple sclerosis (MS). Methods: Forty patients with relapsing MS randomized to either treatment were scanned at 3T at baseline and weeks 24, 48, and 96 follow-up. Twenty-four healthy controls were scanned at weeks 0, 48, and 96. NAA, tCr, tCho, mI, and NAA/tCr were measured in a single large supra-ventricular voxel. Results: There was a time × treatment interaction in NAA/tCr (p = 0.04), primarily driven by opposing tCr trends between treatment groups after 48 weeks of treatment. Patients treated with ocrelizumab showed a possible decline in mI after week 48 week, and stable tCr and tCho levels. Conversely, the interferon beta-1a treated group showed possible increases in mI, tCr, and tCho over 96 weeks. Conclusions: Results from this exploratory study suggest that over 2 years, ocrelizumab reduces gliosis compared with interferon beta-1a, demonstrated by declining ml, and stable tCr and tCho. Ocrelizumab may improve the physiologic milieu by decreasing neurotoxic factors that are generated by inflammatory processes. [ABSTRACT FROM AUTHOR]

Background and Purpose: Previous magnetic resonance spectroscopy (MRS) studies have concluded that hippocampal and parahippocampal metabolite concentrations remain stable during healthy adult aging. However, these studies used short repetition times (TR ≤ 2 seconds), which lead to incomplete longitudinal magnetization recovery, and thus, heavily T1 -weighted measurements. It is important to accurately characterize brain metabolites changes with age to enable appropriate interpretations of MRS findings in the context of neurodegenerative diseases. Our goal was to assess hippocampal brain metabolite concentrations in a large cohort of diversely aged healthy volunteers using a longer TR of 4 seconds.Methods: Left hippocampal MR spectra were collected from 38 healthy volunteers at 3T. Absolute metabolite concentrations were determined for total N-acetyl-aspartate (tNAA), total creatine (tCr), total choline (tCho), glutamate and glutamine (Glx), and myoinositol (mI). Individual partial correlations between each metabolite with age were assessed using demographic information and voxel compartmentation as confounders.Results: Hippocampal tNAA, tCr, tCho, and mI all increased with age (NAA: R2 = .17, P = .041; tCr: R2 = .45, P = .0002; tCho: R2 = .37, P = .001; mI: R2 = .44, P = .0003). There were no relationships between age and signal to noise ratio, linewidth, or scan date, indicating the correlations were not confounded by spectral quality. Furthermore, we did not observe a trend with age in the voxel tissue compartmentations.Conclusions: We observed increases in hippocampal/parahippocampal metabolite concentrations with age, a finding that is in contrast to previous literature. Our findings illustrate the importance of using a sufficiently long TR in MRS to avoid T1 -relaxation effects influencing the measurement of absolute metabolite concentrations. [ABSTRACT FROM AUTHOR]

Radiation necrosis mostly occurs in and near the radiation field. We used magnetic resonance imaging to study radiation‐induced necrosis of atypical onset, severity, and extent following stereotactic radiosurgery for a symptomatic arteriovenous malformation. Susceptibility‐sensitive imaging, T1‐relaxation, myelin water imaging, and magnetic resonance spectroscopy were acquired three times up to 52 months postradiosurgery. Increasing water content outside the radiation field, contralateral neuronal loss, and gliosis were detected over time. Our findings suggest that radiation‐induced vasculopathic changes spread more diffusely than previously described. An autoimmune response to brain antigens could underlie white matter changes outside the initial radiation field. [ABSTRACT FROM AUTHOR]

Background: We previously reported that patients with early-stage bipolar disorder, but not healthy comparison controls, had body mass index (BMI)-related volume reductions in limbic brain areas, suggesting that the structural brain changes characteristic of bipolar disorder were more pronounced with increased weight.Aims: To determine whether the most consistently reported neurochemical abnormality in bipolar disorder, increased glutamate/glutamine (Glx), was also more prominent with higher BMI.Method: We used single-voxel proton magnetic resonance spectroscopy to measure hippocampal Glx in 51 patients with first-episode mania (mean BMI = 24.1) and 28 healthy controls (mean BMI = 23.3).Results: In patients, but not healthy controls, linear regression demonstrated that higher BMI predicted greater Glx. Factorial ANCOVA showed a significant BMI × diagnosis interaction, confirming a distinct effect of weight on Glx in patients.Conclusions: Together with our volumetric studies, these results suggest that higher BMI is associated with more pronounced structural and neurochemical limbic brain changes in bipolar disorder, even in early-stage patients with low obesity rates. [ABSTRACT FROM AUTHOR]

Abstract: Multiecho T2 relaxation measurements offer specific information about myelin content through the myelin water fraction (MWF), as well as about the water environments through the intra- and extra-cellular (IE), and global, geometric mean T2 (GMT2) times. While these measurements have yielded new insights into brain development and pathologies, they have yet to be thoroughly investigated in the spinal cord. The goals of this study were: (1) to apply a new 3D multiecho T2 relaxation measurement in the cervical spine with sufficient axial resolution to distinguish grey and white matter; (2) to perform a pilot reliability assessment of the resulting MWF and GMT2 measures in a target population; and (3) to detect differences in these measures between a younger cohort (20–30years of age) and an older cohort (50–75years of age) of healthy adults. The results demonstrated that the MWF in younger healthy adults follows the known pattern of lower myelin content in grey matter (mean (95% confidence interval)) (0.049 (0.030–0.067)) as compared to white matter (0.296 (0.275–0.317), p<0.001). The reliability coefficients were 0.65 and 0.82 for the MWF in the dorsal (DC) and lateral column (LC) white matter, respectively; 0.79 and 0.52 for the IE GMT2; and 0.74 and 0.73 for the global GMT2. Significantly lower MWF were found in the older adults than in the younger adults (DC p=0.014; LC p=0.012), as well as lower IE GMT2 times (DC p=0.008; LC p=0.042), however, the global GMT2 times did not show any differences. These changes in MWF and IE GMT2 times, but not in global GMT2 times, indicate that multiecho T2 relaxation measures are sensitive to changes in myelin integrity and cell morphology that may not be apparent on conventional T2 weighted images. [ABSTRACT FROM AUTHOR]

Introduction: Clinical trials that involve participants from multiple sites necessitate standardized and reliable quantitative MRI outcomes to detect significant group differences over time. Metabolite concentrations measured by proton MRS (1H‐MRS) provide valuable information about in vivo metabolism of the central nervous system, but can vary based on the acquisition and quantitation methods used by different MR sites. Therefore, we investigated the intra‐ and inter‐site reproducibility of metabolite concentrations measured by 1H‐MRS on MRI scanners from a single manufacturer across six sites. Methods: Five healthy controls were scanned twice within 24 h at six participating 3 T MR sites with large single‐voxel PRESS (TE/TR/NSA = 36 ms/4000 ms/56) and anatomical images for voxel positioning and correction of partial volume relaxation. Absolute metabolite concentrations were calculated relative to the T1 and T2 relaxation corrected signal from water. Intra‐ and inter‐site reproducibility was assessed using Bland–Altman plots and intra‐ and inter‐site coefficient of variation (CoV) as well as intra‐ and inter‐site intra‐class correlation coefficient. Results: The median intra‐site CoVs for the five major metabolite concentrations ([NAA], [tCr], [Glu], [tCho] and [Ins]) were between 2.5 and 5.3%. Inter‐site CoVs were also low, with the median CoVs for all metabolites between 3.7 and 6.4%. Metabolite concentrations were robust to small inconsistencies in voxel placement and site was not the driving factor in the variance of the measurement of any metabolite concentration. Between‐subject differences accounted for the majority of the concentration variability for creatine, choline and myo‐inositol (42–65% of the variance). Conclusion: A large single‐voxel 1H‐MRS acquisition from a single manufacturer's MRI scanner is highly reproducible and reliable for multi‐site clinical trials. [ABSTRACT FROM AUTHOR]

Background Progressive solitary sclerosis is a unifocal demyelinating disease recently proposed as a possible multiple sclerosis variant. Objective To compare myelin content and brain metabolite ratio qualitatively in the normal-appearing white matter of progressive solitary sclerosis cases compared to multiple sclerosis and healthy control participants. Methods Case report. Results Progressive solitary sclerosis cases showed abnormal myelin in normal-appearing white matter tracts and global normal-appearing white matter as well as lower N-acetyl-aspartate to total creatine ratio compared to multiple sclerosis and healthy control groups. Conclusion Despite a single demyelinating lesion along the corticospinal tract in progressive solitary sclerosis, we showed evidence of more extensive abnormality within the normal-appearing white matter. [ABSTRACT FROM AUTHOR]

Regional variations in glutamate levels across the cingulate cortex, decreasing rostral to caudal, have been observed previously in healthy volunteers with proton magnetic resonance spectroscopy ( 1 H-MRS) at 7 T. This study sought to explore cingulate cortex glutamate trends further by investigating whether a similar gradient could be detected at 3 T, the effect of sex, as well as whether individual variations gave rise to more than one regional glutamate pattern. 1 H-MRS at 3 T [Phillips Elition; semi-localization by adiabatic selective refocusing, echo time (TE)/repetition time (TR) = 32/5,000] was acquired in four cingulate regions: the anterior, midanterior, midposterior, and posterior cortices, in 50 healthy participants (26 F) scanned at a fixed time of day and with controlled food intake. K -means clustering was used to characterize the presence of distinct regional patterns, which were then compared between sex and clusters. In addition, cortical thickness was compared between clusters and in relation to glutamate. Aligned with 7 T findings, we demonstrated that average glutamate levels decreased rostral to caudal in the healthy cingulate cortex. No effect of sex was found, suggesting similar resting glutamate levels in both sexes. Interestingly, the majority of participants were characterized by glutamate levels that did not significantly change across the cingulate (65%). Different regional patterns in cortical thickness between clusters offer further evidence into these distinct glutamate variations and suggest that both a neuroanatomical and a functional role may lead to these findings. This study provides a much-needed foundation for further research to determine the implications of neurotransmission patterns in health and disease. NEW & NOTEWORTHY In a large, sex-balanced sample of healthy individuals, we demonstrate that average regional differences (rostral to caudal) in cingulate cortex glutamate exist, using optimized experimental conditions and 3 T magnetic resonance spectroscopy techniques. Results align with observations from 7 T. A novel clustering approach was introduced to determine the number of patterns for glutamate in the healthy adult brain for the first time. These findings demonstrate that regional differences are detectable at 3 T when present and suggest the occurrence of multiple glutamate metabolism patterns in the cingulate.

Purpose: Myelin water imaging (MWI) provides a valuable biomarker for myelin, but clinical application has been restricted by long acquisition times. Accelerating the standard multi-echo T 2 acquisition with gradient echoes (GRASE) or by 2D multi-slice data collection results in image blurring, contrast changes, and other issues. Compressed sensing (CS) can vastly accelerate conventional MRI. In this work, we assessed the use of CS for in vivo human MWI, using a 3D multi spin-echo sequence., Methods: We implemented multi-echo T 2 relaxation imaging with compressed sensing (METRICS) and METRICS with partial Fourier acceleration (METRICS-PF). Scan-rescan data were acquired from 12 healthy controls for assessment of repeatability. MWI data were acquired for METRICS in 9 m:58 s and for METRICS-PF in 7 m:25 s, both with 1.5 × 2 × 3 mm 3 voxels, 56 echoes, 7 ms ΔTE, and 240 × 240 × 170 mm 3 FOV. METRICS was compared with a novel multi-echo spin-echo gold-standard (MSE-GS) MWI acquisition, acquired for a single additional subject in 2 h:2 m:40 s., Results: METRICS/METRICS-PF myelin water fraction had mean: repeatability coefficient 1.5/1.1, coefficient of variation 6.2/4.5%, and intra-class correlation coefficient 0.79/0.84. Repeatability metrics comparing METRICS with METRICS-PF were similar, and both sequences agreed with reference values from literature. METRICS images and quantitative maps showed excellent qualitative agreement with those of MSE-GS., Conclusion: METRICS and METRICS-PF provided highly repeatable MWI data without the inherent disadvantages of GRASE or 2D multi-slice acquisition. CS acceleration allows MWI data to be acquired rapidly with larger FOV, higher estimated SNR, more isotropic voxels and more echoes than with previous techniques. The approach introduced here generalizes to any multi-component T 2 mapping application., (© 2020 International Society for Magnetic Resonance in Medicine.)

Background and Purpose: Acquiring and interpreting quantitative myelin-specific MRI data at an individual level is challenging because of technical difficulties and natural myelin variation in the population. To overcome these challenges, we used multiecho T 2 myelin water imaging (MWI) to create T 2 metric healthy population atlases that depict the mean and variation of myelin water fraction (MWF), and intra- and extracellular water mobility as described by geometric mean T 2 (IEGMT 2 )., Methods: Cervical cord MWI was performed at 3T on 20 healthy individuals (10M/10F, mean age: 36 years) and 3 relapsing remitting multiple sclerosis (RRMS) participants (1M/2F, age: 39/42/37 years). Anatomical data were collected for the purpose of image segmentation and registration. Atlases were created by coregistering and averaging T 2 metrics from all controls. Voxel-wise z-score maps from 3 RRMS participants were produced to demonstrate the preliminary utility of the MWF and IEGMT 2 atlases., Results: The average MWF atlas provides a representation of myelin in the spinal cord consistent with well-known spinal cord anatomical characteristics. The IEGMT 2 atlas also depicted structural variations in the spinal cord. Z-score analysis illustrated distinct abnormalities in MWF and IEGMT 2 in the 3 RRMS cases., Conclusions: Our findings highlight the potential for using a quantitative T 2 relaxation metric atlas to visualize and detect pathology in spinal cord. Our MWF and IEGMT 2 atlases (URL: https://sourceforge.net/projects/mwi-spinal-cord-atlases/) can serve as normative references in the cervical spinal cord for other studies., (© 2019 by the American Society of Neuroimaging.)

Radiation necrosis mostly occurs in and near the radiation field. We used magnetic resonance imaging to study radiation-induced necrosis of atypical onset, severity, and extent following stereotactic radiosurgery for a symptomatic arteriovenous malformation. Susceptibility-sensitive imaging, T 1 -relaxation, myelin water imaging, and magnetic resonance spectroscopy were acquired three times up to 52 months postradiosurgery. Increasing water content outside the radiation field, contralateral neuronal loss, and gliosis were detected over time. Our findings suggest that radiation-induced vasculopathic changes spread more diffusely than previously described. An autoimmune response to brain antigens could underlie white matter changes outside the initial radiation field., Competing Interests: Vanessa Wiggermann has nothing to disclose. Emmanuelle Lapointe has received consulting fees from Roche, Biogen, and EMD Serono and speaker fees from Genzyme and EMD Serono. Ludmila Litvin, Carina Graf, and Enedino Hernández‐Torres report no disclosures. Michael McKenzie is on the Steering Committee for a randomized trial in prostate cancer sponsored by Janssen R&D. He has received honoraria from Abbott, Bayer, Amgen, and Ferring as well as from Varian. Irene M Vavasour and Cornelia Laule have no disclosures. Erin L. Macmillan is supported by Philips Healthcare Canada. David Li has received research funding from the Canadian Institute of Health Research and Multiple Sclerosis Society of Canada. He is the Emeritus Director of the UBC MS/MRI Research Group, which has been contracted to perform central analysis of MRI scans for therapeutic trials with Novartis, Perceptives, Roche, and Sanofi‐Aventis. The UBC MS/MRI Research Group has also received grant support for investigator‐initiated independent studies from Genzyme, Merck‐Serono, Novartis, and Roche. He has acted as a consultant to Vertex Pharmaceuticals and served on the Data and Safety Advisory Board for Opexa Therapeutics and Scientific Advisory Boards for Adelphi Group, Celgene, Novartis, and Roche. He has also given lectures which have been supported by nonrestricted education grants from Biogen‐Idec, Novartis, Sanofi‐Genzyme, and Teva. Shannon Kolind has consulted for Acorda and Genzyme. She has received research support from Roche. She is grateful for support from the MS Society of Canada and the Milan & Maureen Ilich Foundation. Alexander Rauscher has received funding from NSERC and the National MS Society as well as speaker fees from Philips Medical. Anthony Traboulsee has received grant funding from the MS Society of Canada, Canadian Institute for Health Research, Roche, and Genzyme; he also received honoraria or travel grants from Teva Canada Innovation, Roche, Merck/EMD Serono, Genzyme, Chugai Pharmaceuticals.

Purpose: To assess the extent of demyelination in cervical spondylotic myelopathy (CSM) using myelin water imaging (MWI) and electrophysiologic techniques., Methods: Somatosensory evoked potentials (SSEPs) and MWI were acquired in 14 patients with CSM and 18 age-matched healthy controls. MWI was performed on a 3.0T whole body magnetic resonance scanner. Myelin water fraction (MWF) was extracted for the dorsal columns and whole cord. SSEPs and MWF were also compared with conventional MRI outcomes, including T2 signal intensity, compression ratio, maximum spinal cord compression (MSCC), and maximum canal compromise (MCC)., Results: Group analysis showed marked differences in T2 signal intensity, compression ratio, MSCC, and MCC between healthy controls and patients with CSM. There were no group differences in MWF and SSEP latencies. However, patients with CSM with pathologic SSEPs exhibited reduction in MWF ( p < 0.05). MWF was also correlated with SSEP latencies., Conclusion: Our findings provide evidence of decreased myelin content in the spinal cord associated with impaired spinal cord conduction in patients with CSM. While conventional MRI are of great value to define the extent of cord compression, they show a limited correlation with functional deficits (i.e., delayed SSEPs). MWI provides independent and complementary readouts to spinal cord compression, with a high specificity to detect impaired conduction., (© 2017 American Academy of Neurology.)