Predictors of multiple sclerosis progression: A systematic review of conventional magnetic resonance imaging studies

INTRODUCTION

Multiple Sclerosis (MS) is a chronic neurodegenerative disorder that affects the central nervous system (CNS) and results in progressive clinical disability and cognitive decline. Currently, there are no specific imaging parameters available for the prediction of longitudinal disability in MS patients. Magnetic resonance imaging (MRI) has linked imaging anomalies to clinical and cognitive deficits in MS. In this study, we aimed to evaluate the effectiveness of MRI in predicting disability, clinical progression, and cognitive decline in MS.

METHODS

In this study, according to PRISMA guidelines, we comprehensively searched the Web of Science, PubMed, and Embase databases to identify pertinent articles that employed conventional MRI in the context of Relapsing-Remitting and progressive forms of MS. Following a rigorous screening process, studies that met the predefined inclusion criteria were selected for data extraction and evaluated for potential sources of bias.

RESULTS

A total of 3028 records were retrieved from database searching. After a rigorous screening, 53 records met the criteria and were included in this study. Lesions and alterations in CNS structures like white matter, gray matter, corpus callosum, thalamus, and spinal cord, may be used to anticipate disability progression. Several prognostic factors associated with the progression of MS, including presence of cortical lesions, changes in gray matter volume, whole brain atrophy, the corpus callosum index, alterations in thalamic volume, and lesions or alterations in cross-sectional area of the spinal cord. For cognitive impairment in MS patients, reliable predictors include cortical gray matter volume, brain atrophy, lesion characteristics (T2-lesion load, temporal, frontal, and cerebellar lesions), white matter lesion volume, thalamic volume, and corpus callosum density.

CONCLUSION

This study indicates that MRI can be used to predict the cognitive decline, disability progression, and disease progression in MS patients over time.

Two Classes of T1 Hypointense Lesions in Multiple Sclerosis With Different Clinical Relevance

Background: Hypointense lesions on T1-weighted images have important clinical relevance in multiple sclerosis patients. Traditionally, spin-echo (SE) sequences are used to assess these lesions (termed black holes), but Fast Spoiled Gradient-Echo (FSPGR) sequences provide an excellent alternative.

Objective: To determine whether the contrast difference between T1 hypointense lesions and the surrounding normal white matter is similar on the two sequences, whether different lesion types could be identified, and whether the clinical relevance of these lesions types are different.

Methods: Seventy-nine multiple sclerosis patients' lesions were manually segmented, then registered to T1 sequences. Median intensity values of lesions were identified on all sequences, then K-means clustering was applied to assess whether distinct clusters of lesions can be defined based on intensity values on SE, FSPGR, and FLAIR sequences. The standardized intensity of the lesions in each cluster was compared to the intensity of the normal appearing white matter in order to see if lesions stand out from the white matter on a given sequence.

Results: 100% of lesions on FSPGR images and 69% on SE sequence in cluster #1 exceeded a standardized lesion distance of Z = 2.3 (p < 0.05). In cluster #2, 78.7% of lesions on FSPGR and only 17.7% of lesions on SE sequence were above this cutoff value, meaning that these lesions were not easily seen on SE images. Lesion count in the second cluster (lesions less identifiable on SE) significantly correlated with the Expanded Disability Status Scale (EDSS) (R: 0.30, p ≤ 0.006) and with disease duration (R: 0.33, p ≤ 0.002).

Conclusion: We showed that black holes can be separated into two distinct clusters based on their intensity values on various sequences, only one of which is related to clinical parameters. This emphasizes the joint role of FSPGR and SE sequences in the monitoring of MS patients and provides insight into the role of black holes in MS.

Efficacy of cladribine tablets in high disease activity patients with relapsing multiple sclerosis: post hoc analysis of subgroups with and without prior disease-modifying drug treatment

BACKGROUND

Relapsing-remitting multiple sclerosis (RRMS) patients with high disease activity (HDA) experience more severe disease than those without HDA. This analysis describes the efficacy of cladribine tablets 3.5 mg/kg in HDA patient subgroups that were either treated with disease-modifying drugs (DMDs) prior to study entry or were treatment naïve.

METHODS

Post hoc analysis of the 96 week Cladribine Tablets Treating Multiple Sclerosis Orally (CLARITY) study compared cladribine tablets 3.5 mg/kg to placebo in subgroups of patients meeting the high relapse activity plus disease activity on treatment definition of HDA. Patients were categorized into either prior DMD treatment or DMD treatment-naïve subgroups. Endpoints included annualized relapse rate (ARR), time to first relapse, time to disability progression and magnetic resonance imaging (MRI) outcomes. No inferential statistical analyses were conducted between subgroups.

RESULTS

The DMD-naïve cohort (n = 187) was larger than the prior-DMD cohort (n = 102). In both the DMD-naïve and prior-DMD cohorts, cladribine tablets were associated with a reduction in ARR (rate ratio [RR]: 0.26; 95% confidence interval [CI]: 0.16-0.42; p < .0001 and RR: 0.55; 95% CI: 0.32-0.95; p = .0324, respectively). In both subgroups, cladribine tablets increased the time to relapse versus placebo (hazard ratio [HR]: 0.36; 95% CI: 0.21-0.62; p = .0002 for DMD-naïve cohort and HR: 0.50; 95% CI: 0.24-1.02; p = .0557 for prior-DMD cohort). Significant differences were observed for all assessed disability and MRI outcomes independently of previous treatment.

CONCLUSION

Post hoc evidence suggests consistent treatment benefits of cladribine tablets 3.5 mg/kg during the 96 week CLARITY study among HDA-RRMS patients who were either previously treated with DMDs or were treatment naïve.

Systematic review of prediction models in relapsing remitting multiple sclerosis

The natural history of relapsing remitting multiple sclerosis (RRMS) is variable and prediction of individual prognosis challenging. The inability to reliably predict prognosis at diagnosis has important implications for informed decision making especially in relation to disease modifying therapies. We conducted a systematic review in order to collate, describe and assess the methodological quality of published prediction models in RRMS. We searched Medline, Embase and Web of Science. Two reviewers independently screened abstracts and full text for eligibility and assessed risk of bias. Studies reporting development or validation of prediction models for RRMS in adults were included. Data collection was guided by the checklist for critical appraisal and data extraction for systematic reviews (CHARMS) and applicability and methodological quality assessment by the prediction model risk of bias assessment tool (PROBAST). 30 studies were included in the review. Applicability was assessed as high risk of concern in 27 studies. Risk of bias was assessed as high for all studies. The single most frequently included predictor was baseline EDSS (n = 11). T2 Lesion volume or number and brain atrophy were each retained in seven studies. Five studies included external validation and none included impact analysis. Although a number of prediction models for RRMS have been reported, most are at high risk of bias and lack external validation and impact analysis, restricting their application to routine clinical practice.

Natural Variation of Vitamin D and Neurofilament Light Chain in Relapsing-Remitting Multiple Sclerosis

Background: High serum levels of 25-hydroxyvitamin D (25(OH)D) have been found among patients with a favorable disease course in relapsing-remitting MS (RRMS), indicating that this may limit clinical deterioration. Clinical deterioration in RRMS correlates with increasing serum levels of neurofilament light chain (NfL).

Objectives: To examine the association between physiological variations in serum 25(OH)D and NfL levels in RRMS patients before and during disease modifying therapy (DMT).

Material and Methods: Serum 25(OH)D and NfL concentrations were measured in 85 newly diagnosed RRMS patients enrolled in a 24-month randomized double-blinded placebo-controlled trial of ω-3 fatty acid supplementation without vitamin D. Patients were without DMT until interferon β-1a (IFN-β) initiation at study month 6. Longitudinal serum measurements and brain magnetic resonance imaging (MRI) were obtained. Associations between 25(OH)D and NfL levels were analyzed with linear regression models for the whole study period and the periods before and during IFN-β treatment. Analyses with adjustment for inflammatory MRI disease activity were also performed.

Results: No significant associations were found between variations in 25(OH)D and NfL levels during the whole study period (p = 0.95), or the periods without (p = 0.78) or with (p = 0.33) IFN-β therapy. Patients with inflammatory MRI disease activity had significantly higher serum NfL levels than patients without inflammatory MRI disease activity [mean (SD) difference 12.6 (2.0) pg/mL, p < 0.01]. Adjustment for this did not change the relationship between 25(OH)D and NfL concentrations.

Conclusion: Natural variations in serum 25(OH)D values do not seem to be associated with alterations in serum NfL concentrations in RRMS patients.

Early perfusion changes in multiple sclerosis patients as assessed by MRI using arterial spin labeling

Background

Gadolinium-perfusion magnetic resonance (MR) identifies gray matter abnormalities in early multiple sclerosis (MS), even in the absence of structural differences. These perfusion changes could be related to the cognitive disability of these patients, especially in the working memory. Arterial spin labeling (ASL) is a relatively recent perfusion technique that does not require intravenous contrast, making the technique especially attractive for clinical research.

Purpose

To verify the perfusion alterations in early MS, even in the absence of cerebral volume changes. To introduce the ASL sequence as a suitable non-invasive method in the monitoring of these patients.

Material and Methods

Nineteen healthy controls and 28 patients were included. The neuropsychological test EDSS and SDMT were evaluated. Cerebral blood flow and bolus arrival time were collected from the ASL study. Cerebral volume and cortical thickness were obtained from the volumetric T1 sequence. Spearman's correlation analyzed the correlation between EDSS and SDMT tests and perfusion data. Differences were considered significant at a level of P < 0.05.

Results

Reduction of the cerebral blood flow and an increase in the bolus arrival time were found in patients compared to controls. A negative correlation between EDSS and thalamus transit time, and between EDSS and cerebral blood flow in the frontal cortex, was found.

Conclusion

ASL perfusion might detect changes in MS patients even in absent structural volumetric changes. More longitudinal studies are needed, but perfusion parameters could be biomarkers for monitoring these patients.

Predictors of Lesion Cavitation After Recent Small Subcortical Stroke

Morphologic evolution of recent small subcortical infarcts (RSSI) ranges from lesion disappearance to lacune formation and the reasons for this variability are still poorly understood. We hypothesized that diffusion tensor imaging (DTI) and blood-brain-barrier (BBB) abnormalities early on can predict tissue damage 1 year after an RSSI. We studied prospectively recruited patients with a symptomatic MRI-defined RSSI who underwent baseline and two pre-specified MRI examinations at 1-3-month and 1-year post-stroke. We defined the extent of long-term tissue destruction, termed cavitation index, as the ratio of the 1-year T1-weighted cavity volume to the baseline RSSI volume on FLAIR. We calculated fractional anisotropy and mean diffusivity (MD) of the RSSI and normal-appearing white matter, and BBB leakage in different tissues on dynamic contrast-enhanced MRI. Amongst 60 patients, at 1-year post-stroke, 44 patients showed some degree of RSSI cavitation on FLAIR, increasing to 50 on T2- and 56 on T1-weighted high-resolution scans, with a median cavitation index of 7% (range, 1-36%). Demographic, clinical, and cerebral small vessel disease features were not associated with the cavitation index. While lower baseline MD of the RSSI (r_s = - 0.371; p = 0.004) and more contrast leakage into CSF (r_s = 0.347; p = 0.007) were associated with the cavitation index in univariable analysis, only BBB leakage in CSF remained independently associated with cavitation (beta = 0.315, p = 0.046). Increased BBB leakage into CSF may indicate worse endothelial dysfunction and increased risk of tissue destruction post RSSI. Although cavitation was common, it only affected a small proportion of the original RSSI.

Diffusion tensor imaging and disability progression in multiple sclerosis: A 4-year follow-up study

OBJECTIVES

Diffusion tensor imaging (DTI) is sensitive technique to detect widespread changes in water diffusivity in the normal-appearing white matter (NAWM) that appears unaffected in conventional magnetic resonance imaging. We aimed to investigate the prognostic value and stability of DTI indices in the NAWM of the brain in an assessment of disability progression in patients with a relapsing-onset multiple sclerosis (MS).

METHODS

Forty-six MS patients were studied for DTI indices (fractional anisotropy (FA), mean diffusivity (MD), radial (RD), and axial (AD) diffusivity) in the NAWM of the corpus callosum (CC) and the internal capsule at baseline and at 1 year after. DTI analysis for 10 healthy controls was also performed at baseline. Simultaneously, focal brain lesion volume and atrophy measurements were done at baseline for MS patients. Associations between DTI indices, volumetric measurements, and disability progression over 4 years were studied by multivariate logistic regression analysis.

RESULTS

At baseline, most DTI metrics differed significantly between MS patients and healthy controls. There was tendency for associations between baseline DTI indices in the CC and disability progression (p < 0.05). Changes in DTI indices over 1 year were observed only in the CC (p < 0.008), and those changes were not found to predict clinical worsening over 4 years. Clear-cut association with disability progression was not detected for baseline volumetric measurements.

CONCLUSION

Aberrant diffusivity measures in the NAWM of the CC may provide additional information for individual disability progression over 4 years in MS with the relapsing-onset disease. CC may be a good target for DTI measurements in monitoring disease activity in MS, and more studies are needed to assess the related prognostic potential.

Multiple Sclerosis: Improved Detection of Active Cerebral Lesions With 3-Dimensional T1 Black-Blood Magnetic Resonance Imaging Compared With Conventional 3-Dimensional T1 GRE Imaging

OBJECTIVES

The aim of this study was to assess the diagnostic accuracy of a modified high-resolution whole-brain three-dimensional T1-weighted black-blood sequence (T1-weighted modified volumetric isotropic turbo spin echo acquisition [T1-mVISTA]) in comparison to a standard three-dimensional T1-weighted magnetization-prepared rapid gradient echo (MP-RAGE) sequence for detection of contrast-enhancing cerebral lesions in patients with relapsing-remitting multiple sclerosis (MS).

MATERIALS AND METHODS

After institutional review board approval and informed consent, 22 patients (8 men; aged 31.0 ± 9.2 years) with relapsing-remitting MS were included in this monocentric prospective cohort study.Contrast-enhanced T1-mVISTA and MP-RAGE, both with 0.8 mm resolution, were performed in all patients. In a substudy of 12 patients, T1-mVISTA was compared with a T1-mVISTA with 1.0 mm resolution (T1-mVISTA_1.0). Reference lesions were defined by an experienced neuroradiologist using all available sequences and served as the criterion standard. T1-mVISTA, T1-mVISTA_1.0, and MP-RAGE sequences were read in random order 4 weeks apart. Image quality, visual contrast enhancement, contrast-to-noise-ratio (CNR), diagnostic confidence, and lesion size were assessed and compared by Wilcoxon and Mann-Whitney U tests.

RESULTS

Eleven of 22 patients displayed contrast-enhancing lesions. Visual contrast enhancement, CNR, and diagnostic confidence of contrast-enhancing MS lesions were significantly increased in T1-mVISTA compared with MP-RAGE (P < 0.001). Significantly more contrast-enhancing lesions were detected with T1-mVISTA than with MP-RAGE (71 vs 39, respectively; P < 0.001). With MP-RAGE, 25.6% of lesions were missed in the initial reading, whereas only 4.2% of lesions were missed with T1-mVISTA. Increase of the voxel volume from 0.8 mm to 1.0 mm isotropic in T1-mVISTA_1.0 did not affect the detectability of lesions, whereas scan time was decreased from 4:43 to 1:55 minutes.

CONCLUSIONS

Three-dimensional T1-mVISTA improves the detection rates of contrast-enhancing cerebral MS lesions compared with conventional 3D MP-RAGE sequences by increasing CNR of lesions and might, therefore, be useful in patient management.

Onset of secondary progressive multiple sclerosis is not influenced by current relapsing multiple sclerosis therapies

BACKGROUND

Disease-modifying therapies are thought to reduce the conversion rate to secondary progressive multiple sclerosis.

OBJECTIVE

To explore the rate, chronology, and contributing factors of conversion to the progressive phase in treated relapsing-remitting multiple sclerosis patients.

METHODS

Our study included 204 patients treated for relapsing-remitting multiple sclerosis between 1995 and 2002, prospectively followed to date. Kaplan-Meier analysis was applied to estimate the time until secondary progressive multiple sclerosis conversion, and multivariate survival analysis with a Cox regression model was used to analyse prognostic factors.

RESULTS

Relapsing-remitting multiple sclerosis patients were continuously treated for 13 years (SD 4.5); 36.3% converted to secondary progressive multiple sclerosis at a mean age of 42.6 years (SD 10.6), a mean time of 8.2 years (SD 5.2) and an estimated mean time of 17.2 years (range 17.1-18.1). A multifocal relapse, age older than 34 years at disease onset and treatment failure independently predicted conversion to secondary progressive multiple sclerosis but did not influence the time to reach an Expanded Disability Status Scale of 6.0.

CONCLUSIONS

The favourable influence of disease-modifying therapies on long-term disability in relapsing-remitting multiple sclerosis is well established. However, the time to progression onset and the subsequent clinical course in treated patients seem similar to those previously reported in natural history studies. More studies are needed to clarify the effect of disease-modifying therapies once the progressive phase has been reached.

A serial 10-year follow-up study of brain atrophy and disability progression in RRMS patients

BACKGROUND

We explored the evolution of brain atrophy in relation to development of confirmed disability progression (CDP) on serial 1.5T magnetic resonance imaging (MRI) scans over a 10-year period in 181 patients with early relapsing-remitting multiple sclerosis (RRMS).

METHODS

At 10-year follow-up, they were divided into those with (100) or without (76) CDP (confirmed after 48 weeks). Changes in whole brain (WB), cortical, gray matter (GM), white matter, and ventricular cerebrospinal fluid (vCSF) volumes were calculated on three-dimensional T1-weighted (3D-T1) scans between all available time points.

RESULTS

In multiple sclerosis (MS) patients with CDP compared to those without, the greatest effect size percentage volume change from baseline to follow-up was detected for WB (d = 0.55, -7.5% vs -5.2%, p < 0.001), followed by vCSF (d = 0.51, +41.1% vs +25.7%, p < 0.001), cortical (d = 0.49, -7.7% vs -6.2%, p = 0.001), and GM (d = 0.40, -7.1% vs -5.8%, p = 0.006) volumes. Mixed-effects model analysis, adjusted for age, sex, and treatment change, showed significant interactions between CDP status and percentage changes for WB and vCSF (p < 0.001), cortical (p = 0.02), and GM (p = 0.04) volumes.

CONCLUSIONS

WB and cortical atrophy, and enlargement of vCSF spaces are associated with development of CDP on serial yearly MRI assessments over a period of 10 years.

MRI criteria for the diagnosis of multiple sclerosis: MAGNIMS consensus guidelines

In patients presenting with a clinically isolated syndrome, MRI can support and substitute clinical information in the diagnosis of multiple sclerosis by showing disease dissemination in space and time and by helping to exclude disorders that can mimic multiple sclerosis. MRI criteria were first included in the diagnostic work-up for multiple sclerosis in 2001, and since then several modifications to the criteria have been proposed in an attempt to simplify lesion-count models for showing disease dissemination in space, change the timing of MRI scanning to show dissemination in time, and increase the value of spinal cord imaging. Since the last update of these criteria, new data on the use of MRI to establish dissemination in space and time have become available, and MRI technology has improved. State-of-the-art MRI findings in these patients were discussed in a MAGNIMS workshop, the goal of which was to provide an evidence-based and expert-opinion consensus on proposed modifications to MRI criteria for the diagnosis of multiple sclerosis.

Brain atrophy and lesion load predict long term disability in multiple sclerosis

OBJECTIVE

To determine whether brain atrophy and lesion volumes predict subsequent 10 year clinical evolution in multiple sclerosis (MS).

DESIGN

From eight MAGNIMS (MAGNetic resonance Imaging in MS) centres, we retrospectively included 261 MS patients with MR imaging at baseline and after 1-2 years, and Expanded Disability Status Scale (EDSS) scoring at baseline and after 10 years. Annualised whole brain atrophy, central brain atrophy rates and T2 lesion volumes were calculated. Patients were categorised by baseline diagnosis as primary progressive MS (n=77), clinically isolated syndromes (n=18), relapsing-remitting MS (n=97) and secondary progressive MS (n=69). Relapse onset patients were classified as minimally impaired (EDSS=0-3.5, n=111) or moderately impaired (EDSS=4-6, n=55) according to their baseline disability (and regardless of disease type). Linear regression models tested whether whole brain and central atrophy, lesion volumes at baseline, follow-up and lesion volume change predicted 10 year EDSS and MS Severity Scale scores.

RESULTS

In the whole patient group, whole brain and central atrophy predicted EDSS at 10 years, corrected for imaging protocol, baseline EDSS and disease modifying treatment. The combined model with central atrophy and lesion volume change as MRI predictors predicted 10 year EDSS with R(2)=0.74 in the whole group and R(2)=0.72 in the relapse onset group. In subgroups, central atrophy was predictive in the minimally impaired relapse onset patients (R(2)=0.68), lesion volumes in moderately impaired relapse onset patients (R(2)=0.21) and whole brain atrophy in primary progressive MS (R(2)=0.34).

CONCLUSIONS

This large multicentre study points to the complementary predictive value of atrophy and lesion volumes for predicting long term disability in MS.