Revere P. Kinkel

In vivo imaging of cortical pathology in multiple sclerosis using ultra-high field MRI

Objective: We used ultra-high field MRI to visualize cortical lesion types described by neuropathology in 16 patients with multiple sclerosis (MS) compared with 8 age-matched controls; to characterize the contrast properties of cortical lesions including T2*, T2, T1, and phase images; and to investigate the relationship between cortical lesion types and clinical data. Methods: We collected, on a 7-T scanner, 2-dimensional fast low-angle shot (FLASH)-T2*-weighted spoiled gradient-echo, T2-weighted turbo spin-echo (TSE) images (0.33 × 033 × 1 mm3), and a 3-dimensional magnetization-prepared rapid gradient echo. Results: Overall, 199 cortical lesions were detected in patients on both FLASH-T2* and T2-TSE scans. Seven-tesla MRI allowed for characterization of cortical plaques into type I (leukocortical), type II (intracortical), and type III/IV (subpial extending partly or completely through the cortical width) lesions as described histopathologically. Types III and IV were the most frequent type of cortical plaques (50.2%), followed by type I (36.2%) and type II (13.6%) lesions. Each lesion type was more frequent in secondary progressive than in relapsing–remitting MS. This difference, however, was significant only for type III/IV lesions. T2*-weighted images showed the highest, while phase images showed the lowest, contrast-to-noise ratio for all cortical lesion types. In patients, the number of type III/IV lesions was associated with greater disability (p < 0.02 by Spearman test) and older age (p < 0.04 by Spearman test). Conclusions: Seven-tesla MRI detected different histologic cortical lesion types in our small multiple sclerosis (MS) sample, suggesting, if validated in a larger population, that it may prove a valuable tool to assess the contribution of cortical MS pathology to clinical disability.

Contribution of cortical lesion subtypes at 7T MRI to physical and cognitive performance in MS

Objectives: Evaluate cross-sectionally the contribution of focal cortical lesion (CL) subtypes at ultra-high-field MRI and traditional MRI metrics of brain damage to neurologic disability and cognitive performance in a heterogeneous multiple sclerosis (MS) cohort. Methods: Thirty-four patients with early or established disease including clinically isolated syndrome, relapsing-remitting MS, and secondary progressive MS were scanned on a human 7-tesla (7T) (Siemens) scanner to acquire fast low-angle shot (FLASH) T2*-weighted images for characterization of white matter and deep gray matter lesion volume, and CL types. Patients also underwent anatomical 3T MRI for cortical thickness estimation, and neuropsychological testing within 1 week of the 7T scan. Twenty-seven patient scans were acceptable for further analysis. Neurologic disability was measured using the Expanded Disability Status Scale. Results: Type III-IV CLs had the strongest relationship to physical disability (ρ = 0.670, p < 0.0001). White matter lesion volume and type I CLs are each significantly associated with 6 of 11 neuropsychological test variables. Type III-IV CLs significantly correlate with 4 of 11 neuropsychological test variables whereas type II CLs, deep gray matter lesion volume, and cortical thickness metrics are less frequently associated with cognitive performance. Conclusions: Leukocortical (type I) and subpial (III-IV) CLs identified on 7T FLASH-T2* sequences are potential cortical biomarkers of cognitive and neurologic status in MS.

In vivo evidence of disseminated subpial T2* signal changes in multiple sclerosis at 7 T: A surface-based analysis

Cortical subpial demyelination is frequent in multiple sclerosis (MS) and is closely associated with disease progression and poor neurological outcome. Although cortical lesions have been difficult to detect using conventional MRI, preliminary data using T2*-weighted imaging at ultra-high field 7T MRI showed improved sensitivity for detecting and categorizing different histological types of cortical MS lesions. In this study we combined high-resolution 7T MRI with a surface-based analysis technique to quantify and map subpial T2*-weighted signal changes in seventeen patients with MS. We applied a robust method to register 7T data with the reconstructed cortical surface of each individual and used a general linear model to assess in vivo an increase in subpial T2*-weighted signal in patients versus age-matched controls, and to investigate the spatial distribution of cortical subpial changes across the cortical ribbon. We also assessed the relationship between subpial T2* signal changes at 7T, Expanded Disability Status Scale (EDSS) score and white matter lesion load (WMLL). Patients with MS showed significant T2*-weighted signal increase in the frontal lobes (parsopercularis, precentral gyrus, middle and superior frontal gyrus, orbitofrontal cortex), anterior cingulate, temporal (superior, middle and inferior temporal gyri), and parietal cortices (superior and inferior parietal cortex, precuneus), but also in occipital regions of the left hemisphere. We found significant correlations between subpial T2*-weighted signal and EDSS score in the precentral gyrus (ρ=0.56, P=0.02) and between T2*-weighted signal and WMLL in the lateral orbitofrontal, superior parietal, cuneus, precentral and superior frontal regions. Our data support the presence of disseminated subpial increases in T2* signal in subjects with MS, which may reflect the diffuse subpial pathology described in neuropathology.

Steroid-responsive neurologic relapses in a child with a proteolipid protein-1 mutation

A 10-year-old boy developed corticosteroid-responsive relapsing neurologic signs, including nystagmus and ataxia. MRI revealed multifocal T2 white matter hyperintensities; several were gadolinium-enhancing. CSF contained oligoclonal bands. Although the patient met criteria for multiple sclerosis (MS), the proteolipid protein-1 gene (PLP1) contained a mutation in exon 3B (c.409C>T), predicting a tryptophan-for-arginine substitution. This case raises questions about the role of inflammation in PLP1-related disorders and, conversely, PLP1 mutations in MS.

Beyond focal cortical lesions in MS: An in vivo quantitative and spatial imaging study at 7T

Objectives: Using quantitative T2* 7-tesla (7T) MRI as a marker of demyelination and iron loss, we investigated, in patients with relapsing-remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS), spatial and tissue intrinsic characteristics of cortical lesion(s) (CL) types, and structural integrity of perilesional normal-appearing cortical gray matter (NACGM) as a function of distance from lesions. Methods: Patients with MS (18 RRMS, 11 SPMS), showing at least 2 CL, underwent 7T T2* imaging to obtain (1) magnitude images for segmenting focal intracortical lesion(s) (ICL) and leukocortical lesion(s) (LCL), and (2) cortical T2* maps. Anatomical scans were collected at 3T for cortical surface reconstruction using FreeSurfer. Seventeen age-matched healthy participants served as controls. Results: ICL were predominantly located in sulci of frontal, parietal, and cingulate cortex; LCL distribution was more random. In MS, T2* was higher in both ICL and LCL, indicating myelin and iron loss, than in NACGM (p < 0.00003) irrespective of CL subtype and MS phenotype. T2* was increased in perilesional cortex, tapering away from CL toward NACGM, the wider changes being for LCL in SPMS. NACGM T2* was higher in SPMS relative to RRMS (p = 0.006) and healthy cortex (p = 0.02). Conclusions: CL had the same degree of demyelination and iron loss regardless of lesion subtype and disease stage. Cortical damage expanded beyond visible CL, close to lesions in RRMS, and more diffusely in SPMS. Evaluation of NACGM integrity, beyond focal CL, could represent a surrogate marker of MS progression.

Gender effects on intramuscular interferon beta-1a in relapsing-remitting multiple sclerosis: analysis of 1406 patients

Background: We aimed to evaluate effects of gender on efficacy and safety of intramuscular (IM) interferon beta (IFNβ)-1a in patients with relapsing–remitting MS (RRMS) or clinically isolated syndromes (CIS) characteristic of early MS. Methods: Pooled data from 1406 (1027 women; 379 men) patients enrolled in five clinical studies of IM IFNβ-1a were analyzed. One analysis examined data for all patients treated with IM IFNβ-1a from all studies. Separate analyses were conducted of pooled IM IFNβ-1a-treated groups from all studies and pooled IFNβ-1a-treated and placebo-treated patients from the placebo-controlled studies. Outcome measures included time to first relapse, annualized relapse rate, time to disability progression, number of gadolinium-enhanced lesions, adverse events, laboratory evaluations, and neutralizing antibodies. Results: All efficacy assessments indicated similar treatment effects of IM IFNβ-1a in men and women with no significant treatment-by-gender interactions. Women reported more headaches, urinary tract infections, and depression in the analysis; however, these were also common in women who received placebo. Men reported more frequent flu-like symptoms in the placebo-controlled studies only. There were no other differences in the safety profile of IM IFNβ-1a between men and women. Conclusions: We conclude that no significant gender-related differences were found in the efficacy and safety of IM IFNβ-1a in patients with RRMS or CIS.

The association between intra- and juxta-cortical pathology and cognitive impairment in multiple sclerosis by quantitative T2* mapping at 7 T MRI

Using quantitative T2* at 7 Tesla (T) magnetic resonance imaging, we investigated whether impairment in selective cognitive functions in multiple sclerosis (MS) can be explained by pathology in specific areas and/or layers of the cortex. Thirty-one MS patients underwent neuropsychological evaluation, acquisition of 7 T multi-echo T2* gradient-echo sequences, and 3 T anatomical images for cortical surfaces reconstruction. Seventeen age-matched healthy subjects served as controls. Cortical T2* maps were sampled at various depths throughout the cortex and juxtacortex. Relation between T2*, neuropsychological scores and a cognitive index (CI), calculated from a principal component analysis on the whole battery, was tested by a general linear model. Cognitive impairment correlated with T2* increase, independently from white matter lesions and cortical thickness, in cortical areas highly relevant for cognition belonging to the default-mode network (p < 0.05 corrected). Dysfunction in different cognitive functions correlated with longer T2* in selective cortical regions, most of which showed longer T2* relative to controls. For most tests, this association was strongest in deeper cortical layers. Executive dysfunction, however, was mainly related with pathology in juxtameningeal cortex. T2* explained up to 20% of the variance of the CI, independently of conventional imaging metrics (adjusted-R2: 52–67%, p < 5.10− 4). Location of pathology across the cortical width and mantle showed selective correlation with impairment in differing cognitive domains. These findings may guide studies at lower field strength designed to develop surrogate markers of cognitive impairment in MS.

Is the Relationship between Cortical and White Matter Pathologic Changes in Multiple Sclerosis Spatially Specific? A Multimodal 7-T and 3-T MR Imaging Study with Surface and Tract-based Analysis

PURPOSE To investigate in vivo the spatial specificity of the interdependence between intracortical and white matter (WM) pathologic changes as function of cortical depth and distance from the cortex in multiple sclerosis (MS), and their independent contribution to physical and cognitive disability. MATERIALS AND METHODS This study was institutional review board-approved and participants gave written informed consent. In 34 MS patients and 17 age-matched control participants, 7-T quantitative T2* maps, 3-T T1-weighted anatomic images for cortical surface reconstruction, and 3-T diffusion tensor images (DTI) were obtained. Cortical quantitative T2* maps were sampled at 25%, 50%, 75% depth from pial surface. Tracts of interest were reconstructed by using probabilistic tractography. The relationship between DTI metrics voxelwise of the tracts and cortical integrity in the projection cortex was tested by using multilinear regression models. RESULTS In MS, DTI abnormal findings along tracts correlated with quantitative T2* changes (suggestive of iron and myelin loss) at each depth of the cortical projection area (P < .01, corrected). This association, however, was not spatially specific because abnormal findings in WM tracts also related to cortical pathologic changes outside of the projection cortex of the tract (P < .001). Expanded Disability Status Scale pyramidal score was predicted by axial diffusivity along the corticospinal tract (β = 4.6 × 10(3); P < .001), Symbol Digit Modalities Test score by radial diffusivity along the cingulum (β = -4.3 × 10(4); P < .01), and T2* in the cingulum cortical projection at 25% depth (β = -1.7; P < .05). CONCLUSION Intracortical and WM injury are concomitant pathologic processes in MS, which are not uniquely distributed according to a tract-cortex-specific pattern; their association may reflect a common stage-dependent mechanism.

Ten-year follow-up of the ‘minimal MRI lesion’ subgroup from the original CHAMPS Multiple Sclerosis Prevention Trial

Background: Patients with clinically isolated syndrome (CIS) and characteristic magnetic resonance imaging (MRI) lesions are at high risk for multiple sclerosis (MS). However, patients with a minimal MRI lesion burden (a low T2-hyperintense [low T2] lesion count) may have borderline formal diagnostic criteria, presenting a clinical management challenge. Objective: Compare the 10-year disease progression of patients with low and higher T2 lesion counts treated over most intervals. Methods: CIS patients from the original CHAMPS MS trial were retrospectively assigned to low-T2 (first quartile; 2–8 lesions) or higher-T2 (second through fourth quartiles; ≥ 9 lesions) groups using baseline T2 lesion counts. The 5- and 10-year open-label extension of CHAMPS (CHAMPIONS) evaluated conversion to clinically definite MS (CDMS), MRI activity, relapses, and disability. Results: The vast majority of patients showed new disease activity by MRI and/or clinical criteria at 10 years (low-T2 86%; higher-T2 98%). Fewer low-T2 than higher-T2 patients developed CDMS (40% vs. 63%; p = 0.013); low-T2 patients also had fewer new brain lesions, less brain volume loss, and less disability progression. Conclusion: CIS patients with low T2 lesion counts show continued disease activity. However, all assessments of disease progression over 10 years indicated a significantly less severe disease course for low-T2 patients.

Early MRI activity predicts treatment nonresponse with intramuscular interferon beta-1a in clinically isolated syndrome.

OBJECTIVE Determine whether MRI activity 6 months after treatment initiation in the Controlled High-Risk Subjects Avonex® Multiple Sclerosis Prevention Study (CHAMPS) predicted progression to clinically definite multiple sclerosis (CDMS) over the subsequent 30 months in intramuscular interferon beta-1a (IM IFNβ-1a)-treated patients vs placebo-treated patients. METHODS CHAMPS patients were randomized to once-weekly IM IFNβ-1a 30 μg or placebo for up to 36 months. MRI was performed every 6 months until CDMS confirmation. Patient groups were defined based on new T2 and/or Gd+ lesions at 6 months. RESULTS Thirteen IM IFNβ-1a patients (6.7%) and 24 placebo patients (12.6%) developed CDMS prior to month 6 and did not undergo the 6-month MRI. At 6 months, 29.7% of IM IFNβ-1a-treated patients vs 40.9% of placebo-treated patients were defined as having high MRI activity levels (≥2 new T2 and/or ≥2 Gd+ lesions). In this subgroup, estimated cumulative probabilities of CDMS were similar between groups (HR=0.88 [0.44-1.77], p=0.7227). A significant treatment response was seen for patients with <2 new T2 and <2 Gd+ lesions at 6 months (HR=0.39 [0.19-0.82], p=0.0120). CONCLUSION MRI scans 6 months after IM IFNβ-1a initiation in CIS patients predict early treatment non-response. Standardized scanning and monitoring may facilitate early disease management.