Clinically isolated syndromes suggestive of multiple sclerosis, part 2: non-conventional MRI, recovery processes, and management

Vitamin D did not reduce multiple sclerosis disease activity after a clinically isolated syndrome

Low serum levels of 25-hydroxyvitamin D [25(OH)D] and low sunlight exposure are known risk factors for the development of multiple sclerosis. Add-on vitamin D supplementation trials in established multiple sclerosis have been inconclusive. The effects of vitamin D supplementation to prevent multiple sclerosis is unknown. We aimed to test the hypothesis that oral vitamin D3 supplementation in high-risk clinically isolated syndrome (abnormal MRI, at least three T2 brain and/or spinal cord lesions), delays time to conversion to definite multiple sclerosis, that the therapeutic effect is dose-dependent, and that all doses are safe and well tolerated. We conducted a double-blind trial in Australia and New Zealand. Eligible participants were randomized 1:1:1:1 to placebo, 1000, 5000 or 10 000 international units (IU) of oral vitamin D3 daily within each study centre (n = 23) and followed for up to 48 weeks. Between 2013 and 2021, we enrolled 204 participants. Brain MRI scans were performed at baseline, 24 and 48 weeks. The main study outcome was conversion to clinically definite multiple sclerosis based on the 2010 McDonald criteria defined as either a clinical relapse or new brain MRI T2 lesion development. We included 199 cases in the intention-to-treat analysis based on assigned dose. Of these, 116 converted to multiple sclerosis by 48 weeks (58%). Compared to placebo, the hazard ratios (95% confidence interval) for conversion were 1000 IU 0.87 (0.50, 1.50); 5000 IU 1.37 (0.82, 2.29); and 10 000 IU 1.28 (0.76, 2.14). In an adjusted model including age, sex, latitude, study centre and baseline symptom number, clinically isolated syndrome onset site, presence of infratentorial lesions and use of steroids, the hazard ratios (versus placebo) were 1000 IU 0.80 (0.45, 1.44); 5000 IU 1.36 (0.78, 2.38); and 10 000 IU 1.07 (0.62, 1.85). Vitamin D3 supplementation was safe and well tolerated. We did not demonstrate reduction in multiple sclerosis disease activity by vitamin D3 supplementation after a high-risk clinically isolated syndrome.

Unraveling the complex relationship: Multiple sclerosis, urinary tract infections, and infertility

BACKGROUND

Multiple sclerosis (MS) is an immune system disorder that affects the central nervous system (CNS) and progressively damages nerve fibers and protective myelin. People with MS often experience a wide range of complications, including lower urinary tract dysfunction, urinary tract infections (UTIs) and sexual dysfunction. MS is common in young people and can lead to sexual dysfunction (SD) and infertility, which becomes more pronounced as the disease progresses.

RESULTS

Over the past two decades, significant advances have been made in the management of MS, which may slow the progression of the disease and alter its course. However, UTI and SD remain significant challenges for these patients. Awareness of the underlying complications of MS, such as UTIs and infertility, is crucial for prevention, early detection and appropriate treatment, as there is a causal relationship between UTIs and the use of corticosteroids during an attack.

CONCLUSION

This article provides an overview of potential microbial pathogens that contribute to the development of MS, as well as an assessment of people with MS who report UTIs and infertility.

Clinically isolated syndrome: Diagnosis and risk of developing clinically definite multiple sclerosis

INTRODUCTION

In most cases, multiple sclerosis (MS) initially presents as clinically isolated syndrome (CIS). Differentiating CIS from other acute or subacute neurological diseases and estimating the risk of progression to clinically definite MS is essential since presenting a second episode in a short time is associated with poorer long-term prognosis.

DEVELOPMENT

We conducted a literature review to evaluate the usefulness of different variables in improving diagnostic accuracy and predicting progression from CIS to MS, including magnetic resonance imaging (MRI) and such biofluid markers as oligoclonal IgG and IgM bands, lipid-specific oligoclonal IgM bands in the CSF, CSF kappa free light-chain (KFLC) index, neurofilament light chain (NfL) in the CSF and serum, and chitinase 3-like protein 1 (CHI3L1) in the CSF and serum.

CONCLUSIONS

Codetection of oligoclonal IgG bands and MRI lesions reduces diagnostic delays and suggests a high risk of CIS progression to MS. A KFLC index > 10.6 and CSF NfL concentrations > 1150 ng/L indicate that CIS is more likely to progress to MS within one year (40%-50%); 90% of patients with CIS and serum CHI3L1 levels > 33 ng/mL and 100% of those with lipid-specific oligoclonal IgM bands present MS within one year of CIS onset.

Evaluating Magnetic Resonance Diffusion Properties Together with Brain Volumetry May Predict Progression to Multiple Sclerosis

RATIONALE AND OBJECTIVES

Although the gold standard in predicting future progression from clinically isolated syndrome (CIS) to clinically definite multiple sclerosis (CDMS) consists in the McDonald criteria, efforts are being made to employ various advanced MRI techniques for predicting clinical progression. This study's main aim was to evaluate the predictive power of diffusion tensor imaging (DTI) of the brain and brain volumetry to distinguish between patients having CIS with future progression to CDMS from those without progression during the following 2 years and to compare those parameters with conventional MRI evaluation.

MATERIALS AND METHODS

All participants underwent an MRI scan of the brain. DTI and volumetric data were processed and various parameters were compared between the study groups.

RESULTS

We found significant differences between the subgroups of patients differing by future progression to CDMS in most of those DTI and volumetric parameters measured. Fractional anisotropy of water diffusion proved to be the strongest predictor of clinical conversion among all parameters evaluated, demonstrating also higher specificity compared to evaluation of conventional MRI images according to McDonald criteria.

CONCLUSION

Conclusion: Our results provide evidence that the evaluation of DTI parameters together with brain volumetry in patients with early-stage CIS may be useful in predicting conversion to CDMS within the following 2 years of the disease course.

Cerebellar and/or Brainstem Lesions Indicate Poor Prognosis in Multiple Sclerosis: A Systematic Review

Multiple sclerosis is a serious neurological disease that affects millions of people worldwide. Cerebellar and brainstem symptoms are common in the course of multiple sclerosis, but their prognostic value is unclear. This systematic review aimed to determine the relationship between the location of lesions in the cerebellum and/or brainstem and the prognosis in multiple sclerosis. In this systematic review, we searched and comprehensively read articles related to this research topic in Chinese and English electronic databases (PubMed, Embase, Cochrane Library, CNKI, and CBM) using search terms “multiple sclerosis,” “cerebellum,” “brainstem,” “prognosis,” and others. Cerebellar and brainstem clinically isolated syndromes and clinically definite multiple sclerosis were important predictors of transformation (hazard ratio, 2.58; 95% confidence interval, 1.58–4.22). Cerebellar and/or brainstem lesions indicate a poor overall prognosis in multiple sclerosis, but because of inconsistency, more clinical data are needed.

Development of a Prognostic Model for Predicting Multiple Sclerosis After Optic Neuritis: A Secondary Analysis of Data From the Optic Neuritis Treatment Trial

BACKGROUND

Optic neuritis can be the initial manifestation of multiple sclerosis (MS). The purpose of this study was to develop a prognostic model for predicting the risk of MS development among patients with optic neuritis.

METHODS

The data from 388 patients with optic neuritis were retrieved from the Optic Neuritis Treatment Trial (ONTT). Cox proportional hazards regression analysis was used to develop a prognostic model. The performance of the model was assessed by using Harrell's C-index and calibration curves. The rates of MS development were estimated using the Kaplan-Meier method.

RESULTS

Among the enrolled subjects, a total of 154 (39.7%) patients developed clinically definite MS during a median follow-up period of 15.8 years (interquartile range, 7.2-16.9 years). The factors associated with the development of MS were the presence of brain lesions as on baseline MRI, previous nonspecific neurologic symptoms, commencing low-dose corticosteroids treatment, ocular pain, and absence of optic disc/peripapillary hemorrhage. After incorporating these 5 factors into the prognostic model, a C-index of 0.72 (95% confidence interval [CI], 0.69-0.76) and good calibration curves were obtained. The C-index of the model was significantly higher than the C-indexes of any single factor (P < 0.001 in all cases). The model was able to stratify the ONTT patient cohort into 3 risk groups with significantly different intergroup rates of developing MS (rates for developing MS within a 15-year period: high-risk group, 75.7% [95% CI, 65.6%-82.9%], intermediate-risk group, 44.7% [95% CI, 31.4%-55.4%]; and low-risk group, 20.8% [95% CI, 14.2%-26.8%]; log-rank P < 0.001).

CONCLUSIONS

This prognostic model had a better prediction ability when compared with the standard practice that relies solely on using brain lesions on MRI. It can, therefore, help guide decision-making to initiate earlier disease-modifying therapy for patients with optic neuritis at risk of developing MS.

Clinically isolated syndrome: diagnosis and risk of developing clinically definite multiple sclerosis

INTRODUCTION

In most cases, multiple sclerosis (MS) initially presents as clinically isolated syndrome (CIS). Differentiating CIS from other acute or subacute neurological diseases and estimating the risk of progression to clinically definite MS is essential since presenting a second episode in a short time is associated with poorer long-term prognosis.

DEVELOPMENT

We conducted a literature review to evaluate the usefulness of different variables in improving diagnostic accuracy and predicting progression from CIS to MS, including magnetic resonance imaging (MRI) and such biofluid markers as oligoclonal IgG and IgM bands, lipid-specific oligoclonal IgM bands in the CSF, CSF kappa free light-chain (KFLC) index, neurofilament light chain (NfL) in the CSF and serum, and chitinase 3-like protein 1 (CHI3L1) in the CSF and serum.

CONCLUSIONS

Codetection of oligoclonal IgG bands and MRI lesions reduces diagnostic delays and suggests a high risk of CIS progression to MS. A KFLC index > 10.6 and CSF NfL concentrations > 1150 ng/L indicate that CIS is more likely to progress to MS within one year (40-50%); 90% of patients with CIS and serum CHI3L1 levels > 33 ng/mL and 100% of those with lipid-specific oligoclonal IgM bands present MS within one year of CIS onset.

Functional Assessment of Outer and Middle Macular Layers in Multiple Sclerosis

The involvement of macular preganglionic elements’ function, during the neurodegenerative process of multiple sclerosis (MS), is controversial. In this case-control observational and retrospective study, we assessed multifocal electroretinogram (mfERG) responses from 41 healthy Controls, 41 relapsing-remitting MS patients without optic neuritis (ON) (MS-noON Group) and 47 MS patients with ON: 27 with full recovery of high-contrast best corrected visual acuity (BCVA) (MS-ON-G Group) and 20 with poor recovery (between 0.2 and 1 LogMAR) of BCVA, (MS-ON-P Group). In the latter Group, Sd-OCT macular volumes and thicknesses of whole and inner and outer retina were measured. MfERG N1 and P1 implicit times (ITs), and N1-P1 response amplitude densities (RADs), were measured from concentric rings (R) with increasing foveal eccentricity: 0–5° (R1), 5–10° (R2), 10–15° (R3), 15–20° (R4), 20–25° (R5), and from retinal sectors (superior, nasal, inferior and temporal) between 0–15° and 0–25°. In the MS-ON-P Group, mean mfERG RADs detected from R1 (0–5°) and from the central nasal sector (0–15°) were significantly reduced (p < 0.01) with respect to those of the Control, MS-noON and MS-ON-G Groups. No other significant differences between Groups for any mfERG parameters were found. All Sd-OCT measurements, apart from the inner retina macular volume in the central 1 mm, were significantly reduced in MS-ON-P patients compared to Controls. The functional impairment in the MS-ON-P Group was associated but not correlated with structural changes of the outer and inner retinal layers in corresponding retinal Areas and Sectors. Our results suggest that in MS, exclusively after ON with poor recovery of BCVA, the neurodegenerative process can induce dysfunctional mechanisms involving photoreceptors and bipolar cells of the fovea and of the more central nasal macular area.

Morphological Outer Retina Findings in Multiple Sclerosis Patients With or Without Optic Neuritis

Purpose: To investigate on the morphology of the macular inner (IR) and outer (OR) layers in multiple sclerosis (MS) patients with and without history of optic neuritis (ON), followed by good or poor recovery of best corrected visual acuity (BCVA). Methods: Thirty-five normal control subjects and 93 relapsing remitting MS patients were enrolled. Of this, 40 MS patients without ON (MS-noON, 40 eyes), 27 with history of ON and good BCVA recovery (MS-ON-G, 27 eyes), and 26 with history of ON and poor BCVA recovery (MS-ON-P, 26 eyes) were studied. Controls and MS patients underwent an extensive ophthalmological examination including spectral-domain optical coherence tomography evaluating in 3 localized macular areas (0-1 mm, Area 1; 1-3 mm, Area 2; 3- 6 mm, Area 3), volumes (MV), and thicknesses (MT) of the whole retina (WR), further segmented in IR and OR. The differences of MV and MT between the groups were tested by ANOVA. In the MS-ON-P group, the correlations between MV and MT and BCVA were evaluated by Pearson's test. Results: When compared to controls, the MS-noON group showed not significantly (p > 0.01) different MVs, whereas MTs were significantly (p < 0.01) reduced in the evaluation of WR and IR. In the MS-ON-G group, a significant (p < 0.01) reduction of WR and IR MVs and MTs was found in Areas 2 and 3; OR MVs and MTs were similar (p > 0.01) to controls. In the MS-ON-P group a significant (p < 0.01) reduction of WR, IR, and OR MVs and MTs was detected in all areas; the BCVA reduction was significantly (p < 0.01) correlated with WR and IR MVs and MTs. Conclusions: In MS without history of ON or when ON is followed by a good BCVA recovery, the neurodegenerative process is limited to IR macular layers; in the presence of ON, with a poor BCVA recovery, a morphological impairment of both IR and OR macular layers occurs.

An Overview of the Intrinsic Role of Citrullination in Autoimmune Disorders

A protein undergoes many types of posttranslation modification. Citrullination is one of these modifications, where an arginine amino acid is converted to a citrulline amino acid. This process depends on catalytic enzymes such as peptidylarginine deiminase enzymes (PADs). This modification leads to a charge shift, which affects the protein structure, protein-protein interactions, and hydrogen bond formation, and it may cause protein denaturation. The irreversible citrullination reaction is not limited to a specific protein, cell, or tissue. It can target a wide range of proteins in the cell membrane, cytoplasm, nucleus, and mitochondria. Citrullination is a normal reaction during cell death. Apoptosis is normally accompanied with a clearance process via scavenger cells. A defect in the clearance system either in terms of efficiency or capacity may occur due to massive cell death, which may result in the accumulation and leakage of PAD enzymes and the citrullinated peptide from the necrotized cell which could be recognized by the immune system, where the immunological tolerance will be avoided and the autoimmune disorders will be subsequently triggered. The induction of autoimmune responses, autoantibody production, and cytokines involved in the major autoimmune diseases will be discussed.

Practice guideline recommendations summary: Disease-modifying therapies for adults with multiple sclerosis: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

OBJECTIVE

To develop recommendations for disease-modifying therapy (DMT) for multiple sclerosis (MS).

METHODS

A multidisciplinary panel developed DMT recommendations, integrating findings from a systematic review; followed an Institute of Medicine-compliant process to ensure transparency and patient engagement; and developed modified Delphi consensus-based recommendations concerning starting, switching, and stopping DMTs pertinent to people with relapsing-remitting MS, secondary progressive MS, primary progressive MS, and clinically isolated syndromes of demyelination. Recommendations were supported by structured rationales, integrating evidence from one or more sources: systematic review, related evidence (evidence not from the systematic review), principles of care, and inference from evidence.

RESULTS

Thirty recommendations were developed: 17 on starting DMTs, including recommendations on who should start them; 10 on switching DMTs if breakthrough disease develops; and 3 on stopping DMTs. Recommendations encompassed patient engagement strategies and individualization of treatment, including adherence monitoring and disease comorbidity assessment. The panel also discussed DMT risks, including counseling about progressive multifocal leukoencephalopathy risk in people with MS using natalizumab, fingolimod, rituximab, ocrelizumab, and dimethyl fumarate; and made suggestions for future research to evaluate relative merits of early treatment with higher potency DMTs vs standard stepped-care protocols, DMT comparative effectiveness, optimal switching strategies, long-term effects of DMT use, definitions of highly active MS, and effects of treatment on patient-specified priority outcomes. This guideline reflects the complexity of decision-making for starting, switching, or stopping MS DMTs. The field of MS treatment is rapidly changing; the Academy of Neurology development process includes planning for future updates.

Classification of Multiple Sclerosis Clinical Profiles via Graph Convolutional Neural Networks

Recent advances in image acquisition and processing techniques, along with the success of novel deep learning architectures, have given the opportunity to develop innovative algorithms capable to provide a better characterization of neurological related diseases. In this work, we introduce a neural network based approach to classify Multiple Sclerosis (MS) patients into four clinical profiles. Starting from their structural connectivity information, obtained by diffusion tensor imaging and represented as a graph, we evaluate the classification performances using unweighted and weighted connectivity matrices. Furthermore, we investigate the role of graph-based features for a better characterization and classification of the pathology. Ninety MS patients (12 clinically isolated syndrome, 30 relapsing-remitting, 28 secondary-progressive, and 20 primary-progressive) along with 24 healthy controls, were considered in this study. This work shows the great performances achieved by neural networks methods in the classification of the clinical profiles. Furthermore, it shows local graph metrics do not improve the classification results suggesting that the latent features created by the neural network in its layers have a much important informative content. Finally, we observe that graph weights representation of brain connections preserve important information to discriminate between clinical forms.

Optical coherence tomography as a means to characterize visual pathway involvement in multiple sclerosis

PURPOSE OF REVIEW

Optical coherence tomography (OCT) is a noninvasive in-vivo imaging tool that enables the quantification of the various retinal layer thicknesses. Given the frequent involvement of the visual pathway in multiple sclerosis, OCT has become an important tool in clinical practice, research and clinical trials. In this review, the role of OCT as a means to investigate visual pathway damage in multiple sclerosis is discussed.

RECENT FINDINGS

Evidence from recent OCT studies suggests that the peripapillary retinal nerve fibre layer (pRNFL) appears to be an ideal marker of axonal integrity, whereas the macular ganglion cell and inner plexiform layer (GCIP) thickness enables early detection of neuronal degeneration in multiple sclerosis. The thickness of the macular inner nuclear layer (INL) has been suggested as a biomarker for inflammatory disease activity and treatment response in multiple sclerosis. OCT parameters may also be used as an outcome measure in clinical trials evaluating the neuroprotective or regenerative potential of new treatments.

SUMMARY

OCT provides insights into multiple sclerosis beyond the visual pathway. It is capable of quantifying the major pathological hallmarks of the disease, specifically inflammation and neuroaxonal degeneration. OCT, therefore, has the potential to become another mainstay in the monitoring of multiple sclerosis patients.

A computer-aided diagnosis of multiple sclerosis based on mfVEP recordings

Introduction

The aim of this study is to develop a computer-aided diagnosis system to identify subjects at differing stages of development of multiple sclerosis (MS) using multifocal visual-evoked potentials (mfVEPs). Using an automatic classifier, diagnosis is performed first on the eyes and then on the subjects.

Patients

MfVEP signals were obtained from patients with Radiologically Isolated Syndrome (RIS) (n = 30 eyes), patients with Clinically Isolated Syndrome (CIS) (n = 62 eyes), patients with definite MS (n = 56 eyes) and 22 control subjects (n = 44 eyes). The CIS and MS groups were divided into two subgroups: those with eyes affected by optic neuritis (ON) and those without (non-ON).

Methods

For individual eye diagnosis, a feature vector was formed with information about the intensity, latency and singular values of the mfVEP signals. A flat multiclass classifier (FMC) and a hierarchical classifier (HC) were tested and both were implemented using the k-Nearest Neighbour (k-NN) algorithm. The output of the best eye classifier was used to classify the subjects. In the event of divergence, the eye with the best mfVEP recording was selected.

Results

In the eye classifier, the HC performed better than the FMC (accuracy = 0.74 and extended Matthew Correlation Coefficient (MCC) = 0.68). In the subject classification, accuracy = 0.95 and MCC = 0.93, confirming that it may be a promising tool for MS diagnosis.

Conclusion

In addition to amplitude (axonal loss) and latency (demyelination), it has shown that the singular values of the mfVEP signals provide discriminatory information that may be used to identify subjects with differing degrees of the disease.

Impact of the McDonald Criteria 2017 on Early Diagnosis of Relapsing-Remitting Multiple Sclerosis

Multiple sclerosis is a chronic immune mediated demyelinating disease leading to neurological disabilities that need to be diagnosed and treated early. Guidelines on multiple sclerosis diagnosis and monitoring experienced comprehensive changes over the last decades. The first McDonald criteria published in 2001 emphasized the importance of MR imaging but also recognized the role of cerebrospinal fluid diagnostics. The demonstration of an intrathecal immunoglobulin G synthesis is a well-established additional component and has a long tradition in the diagnosis of relapsing-remitting multiple sclerosis. However, the role of cerebrospinal fluid for diagnostic purposes was rather diminished in each revision of the McDonald criteria. In the latest revision of the McDonald criteria of 2017, the detection of an intrathecal immunoglobulin G synthesis as oligoclonal bands experienced a revival. Patients with the first clinical event suggesting multiple sclerosis who fulfill the criteria for dissemination in space can be diagnosed with relapsing-remitting multiple sclerosis when oligoclonal bands in cerebrospinal fluid are detected. The diagnostic sensitivity of these novel criteria with a focus on dissemination in time and oligoclonal bands as a substitute for dissemination in time was published in different cohorts in the last year and is of special interest in this review. Recently published data show that by applying the 2017 McDonald criteria, multiple sclerosis can be diagnosed more frequently at the time of first clinical event as compared to the 2010 McDonald criteria. The main effect was due to the implementation of oligoclonal bands as a substitute for dissemination in time. However, careful differential diagnosis is essential in patients with atypical clinical manifestations to avoid misdiagnoses.

Signaling pathways and therapeutic perspectives related to environmental factors associated with multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated demyelinating disorder of unknown etiology. Both genetic-susceptibility and environment exposures, including vitamin D deficiency, Epstein-Barr viral and Herpesvirus (HHV-6) infections are strongly implicated in the activation of T cells and MS-pathogenesis. Despite precise knowledge of how these factors could be operating alone or in combination to facilitate and aggravate the disease progression, it is clear that prolonged induction of inflammatory molecules and recruitment of other immune cells by the activated T cells results in demyelination and axonal damage. It is imperative to understand the risk factors associated with MS progression and how these factors contribute to disease pathology. Understanding of the underlying mechanisms of what factors triggers activation of T cells to attack myelin antigen are important to strategize therapeutics and therapies against MS. Current review provides a detailed literature to understand the role of both pathogenic and non-pathogenic factors on the impact of MS.

Multi-component relaxation in clinically isolated syndrome: Lesion myelination may predict multiple sclerosis conversion

We performed a longitudinal case-control study on patients with clinically isolated syndrome (CIS) with the aid of quantitative whole-brain myelin imaging. The aim was (1) to parse early myelin decay and to break down its distribution pattern, and (2) to identify an imaging biomarker of the conversion into clinically definite Multiple Sclerosis (MS) based on in vivo measurable changes of myelination.

Imaging and clinical data were collected immediately after the onset of first neurological symptoms and follow-up explorations were performed after 3, 6, and, 12 months. The multi-component Driven Equilibrium Single Pulse Observation of T1/T2 (mcDESPOT) was applied to obtain the volume fraction of myelin water (MWF) in different white matter (WM) regions at every time-point. This measure was subjected to further voxel-based analysis with the aid of a comparison of the normal distribution of myelination measures with an age and sex matched healthy control group. Both global and focal relative myelination content measures were retrieved.

We found that (1) CIS patients at the first clinical episode suggestive of MS can be discriminated from healthy control WM conditions (p < 0.001) and therewith reproduced our earlier findings in late CIS, (2) that deficient myelination in the CIS group increased in T2 lesion depending on the presence of gadolinium enhancement (p < 0.05), and (3) that independently the CIS T2 lesion relative myelin content provided a risk estimate of the conversion to clinically definite MS (Odds Ratio 2.52).

We initially hypothesized that normal appearing WM myelin loss may determine the severity of early disease and the subsequent risk of clinically definite MS development. However, in contrast we found that WM lesion myelin loss was pivotal for MS conversion. Regional myelination measures may thus play an important role in future clinical risk stratification.

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The multicomponent relaxation method mcDESPOT allowed 3D resolved data acquisition appropriate for group comparison and voxel-wise analysis.

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Myelin imaging in early clinically isolated syndrome revealed initial imaging widespread myelin loss even in normal appearing brain tissue.

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In clinically isolated syndrome the myelin measures varied depending on the presence of Gadolinium enhancement.

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Short-term risk of clinically isolated syndrome to convert to multiple sclerosis was determined by myelin measures within white matter lesions.

Non-lesional cerebellar damage in patients with clinically isolated syndrome: DTI measures predict early conversion into clinically definite multiple sclerosis

Background

Today, no specific test for the diagnosis of multiple sclerosis (MS) is available due to the lack of characteristic symptoms at beginning. This circumstance also complicates estimation of disease progression. Recent findings provided evidence for early, non-lesional cerebellar damage in patients with (clinically definite) relapsing-remitting MS.

Objective

To investigate if microstructural cerebellar alterations can also serve as early structural biomarker for disease progression and conversion from clinically isolated syndrome (CIS) to MS.

Methods

46 patients diagnosed with CIS and 26 age-matched healthy controls were admitted to high-resolution MRI including diffusion tensor imaging (DTI) to examine atrophy and microstructural integrity of the cerebellum. Microstructural integrity of cerebellar white matter was assessed by fractional anisotropy (FA) as derived from DTI.

Results

Although all 46 patients of our CIS cohort showed no cerebellar lesions in structural MRI (T1w, T2w, FLAIR), their mean cerebellar FA was already reduced compared to healthy controls. Significant FA reduction at follow-up DTI 6 months after baseline examination was observed. In 16 patients that converted to MS, we found a correlation between initial cerebellar FA and conversion latency (R = 0.71, p < 0.002). Initial cerebellar FA under FA_crit = 0.352 predicted conversion into relapsing-remitting MS within 24 months (FA_crit: mean cerebellar FA of patients with early MS, determined in another study).

Conclusion

DTI seems to reflect early tissue injury in beginning MS, when atrophy and lesions are not yet detectable. Decreased cerebellar FA in patients with CIS might indicate an active and unstable disease stage, resulting in a shorter conversion time into MS.

Prediction of Conversion from Clinically Isolated Syndrome to Multiple Sclerosis According to Baseline Characteristics: A Prospective Study

Objective

Clinically isolated syndrome (CIS) is a clinical state that proceeds with inflammation and demyelination, suggestive of multiple sclerosis (MS) in the central nervous system in the absence of other alternative diagnoses. The purpose of this study was to determine in a prospective cohort, the predictor factors in conversion from CIS to MS on the basis of clinical, magnetic resonance (MR) imaging and cerebrospinal fluid (CSF) findings.

Methods

Forty-one CIS patients were included in this study and followed up for at least two years.

Results

Clinically, polysymptomatic or sensorial involvement, good prognostic factors and complete response to pulse therapy were found to be of prognostic value in conversion to MS. A greater presence of oligoclonal bands in CSF was identified in the converted group (92.8%). In terms of localization, presence of callosal lesion (71.4%), periventricular lesion (97.1%), Gd-enhanced lesion (48.6%), black hole (54.2%) and brainstem lesion (57.1%) was statistically significant in terms of conversion to MS.

Conclusion

A carefully performed neurological assessment of symptoms and signs, and evaluation of lesions on MR combined with CSF findings are important for identifying the risk of conversion to MS. This information may be useful when considering treatment in CIS patients instead of waiting for conversion to MS.

Down-regulation of interleukin 7 receptor (IL-7R) contributes to central nervous system demyelination

Interleukin 7 receptor (IL-7R) has been associated with the pathogenesis of multiple sclerosis (MS), though the mechanisms are not clear. Because myelin expression is highly conserved between zebrafish and mammals, zebrafish have become an ideal model for studying demyelination. We used a transgenic (Tg; mbp:nfsB-egfp) zebrafish line in which oligodendrocytes expressed green fluorescent protein (GFP) from the larval stage to adulthood. Exposing adult transgenic zebrafish to metronidazole induced demyelination that resembled the morphological changes associated with the early stages of MS. The metronidazole-induced demyelination was confirmed by magnetic resonance imaging (MRI) for the first time. Microarray analysis revealed down-regulation of IL-7R during demyelination. Targeted knockdown of IL-7R demonstrated that IL-7R is essential for myelination in embryonic and larval zebrafish. Moreover, IL-7R down-regulation induced signaling via the JAK/STAT pathway leading to apoptosis in oligodendrocytes. These findings contribute to our understanding of the role of IL-7R in demyelination, and provide a rationale for the development of IL-7R-based therapies for MS and other demyelinating diseases.

Decrease of blood anti-α1,3 Galactose Abs levels in multiple sclerosis (MS) and clinically isolated syndrome (CIS) patients

The etiology of multiple sclerosis (MS) remains elusive. Among the possible causes, the increase of anti-Neu5Gc antibodies during EBV primo-infection of Infectious mononucleosis (IMN) may damage the integrity of the blood-brain barrier facilitating the transfer of EBV-infected B cells and anti-EBV T cell clones in the brain. We investigated the change in titers of anti-Neu5Gc and anti-α1,3 Galactose antibodies in 49 IMN, in 76 MS, and 73 clinically isolated syndrome (CIS) patients, as well as age/gender-matched healthy individuals. Anti-Gal and anti-Neu5Gc are significantly increased during IMN (p=0.02 and p<1.10^-4 respectively), but not in acute CMV primo-infection. We show that, whereas there was no change in anti-Neu5Gc in MS/CIS, the two populations exhibit a significant decrease in anti-Gal (combined p=2.7.10^-3), in contrast with patients with non-MS/CIS central nervous system pathologies. Since anti-Gal result from an immunization against α1,3 Gal, lacking in humans but produced in the gut, our data suggest that CIS and MS patients have an altered microbiota or an altered response to this microbiotic epitope.

Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function that results from immune-mediated inflammation, demyelination, and subsequent axonal damage.

Clinically, most MS patients experience recurrent episodes (relapses) of neurological impairment, but in most cases (60–80%) the course of the disease eventually becomes chronic and progressive, leading to cumulative motor, sensory, and visual disability, and cognitive deficits.

The course of the disease is largely unpredictable and its clinical presentation is variable, but its predilection for certain parts of the CNS, which includes the optic nerves, the brain stem, cerebellum, and cervical spinal cord, provides a characteristic constellation of signs and symptoms. Several variants of MS have been nowadays defined with variable immunopathogenesis, course and prognosis. Many new treatments targeting the immune system have shown efficacy in preventing the relapses of MS and have been introduced to its management during the last decade.

Impairment of Smooth Pursuit as a Marker of Early Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) is a diffuse disease that disrupts wide-ranging cerebral networks. The control of saccades and smooth pursuit are similarly dependent upon widespread networks, with the assessment of pursuit offering an opportunity to examine feedback regulation. We sought to characterize pursuit deficits in MS and to examine their relationship with disease duration.

METHODS

Twenty healthy controls, 20 patients with a clinically isolated syndrome (CIS), and 40 patients with clinically definite MS (CDMS) participated. Thirty-six trials of Rashbass' step-ramp paradigm of smooth pursuit, evenly split by velocity (8.65°, 17.1°, and 25.9°/s) and ramp direction (left/right), were performed. Four parameters were measured: latency of pursuit onset, closed-loop pursuit gain, number of saccades, and summed saccade amplitudes during pursuit. For CDMS patients, these were correlated with disease duration and Expanded Disability Status Scale (EDSS) score.

RESULTS

Closed-loop pursuit gain was significantly lower in CIS than controls at all speeds. CDMS gain was lower than controls at medium pursuit velocity. CDMS patients also displayed longer pursuit latency than controls at all velocities. All patients accumulated increased summed saccade amplitudes at slow and medium pursuit speeds, and infrequent high-amplitude saccades at the fast speed. No pursuit variable significantly correlated with EDSS or disease duration in CDMS patients.

CONCLUSION

Smooth pursuit is significantly compromised in MS from onset. Low pursuit gain and increased saccadic amplitudes may be robust markers of disseminated pathology in CIS and in more advanced MS. Pursuit may be useful in measuring early disease.

A prospective cohort study of vitamin D in optic neuritis recovery

Background:

Vitamin D sufficiency is associated with better inflammatory outcomes in multiple sclerosis (MS). We hypothesize that it is also associated with better long-term neurodegenerative measures.

Objectives:

To show that vitamin D sufficient patients (25-hydroxy vitamin D (25(OH)D) > 80 nmol/L) have better optical coherence tomography (OCT) neuroaxonal measures of ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) thickness after optic neuritis.

Methods:

In this prospective cohort study, acute optic neuritis patients underwent OCT and serum 25(OH)D assessments at baseline and at month 6, with comparisons between vitamin D sufficient and insufficient patients, and men and women. Potential confounding variables were evaluated.

Results:

Of 49 enrolled, 36 had complete, analyzable data. At baseline, vitamin D insufficiency was associated with greater RNFL thickness (134.3 vs. 95.2 µm; p = 0.003) in affected eyes. At month 6, insufficient patients had greater GCL thinning (GCL inter-eye difference: 14.2 vs. 4.0 µm, p = 0.008). Men had greater RNFL and GCL thinning than women (GCL: 61.2 vs. 69.6 µm, p = 0.036).

Conclusion:

Acutely, in optic neuritis, RNFL thickness is increased with vitamin D insufficiency. Chronically, neuronal, and possibly axonal loss are associated with vitamin D insufficiency and male gender, suggesting vitamin D and female gender may confer neuroprotection in optic neuritis, and possibly, central nervous system (CNS) inflammatory disease.

Structural Brain Network Characteristics Can Differentiate CIS from Early RRMS

Focal demyelinated lesions, diffuse white matter (WM) damage, and gray matter (GM) atrophy influence directly the disease progression in patients with multiple sclerosis. The aim of this study was to identify specific characteristics of GM and WM structural networks in subjects with clinically isolated syndrome (CIS) in comparison to patients with early relapsing-remitting multiple sclerosis (RRMS). Twenty patients with CIS, 33 with RRMS, and 40 healthy subjects were investigated using 3 T-MRI. Diffusion tensor imaging was applied, together with probabilistic tractography and fractional anisotropy (FA) maps for WM and cortical thickness correlation analysis for GM, to determine the structural connectivity patterns. A network topology analysis with the aid of graph theoretical approaches was used to characterize the network at different community levels (modularity, clustering coefficient, global, and local efficiencies). Finally, we applied support vector machines (SVM) to automatically discriminate the two groups. In comparison to CIS subjects, patients with RRMS were found to have increased modular connectivity and higher local clustering, highlighting increased local processing in both GM and WM. Both groups presented increased modularity and clustering coefficients in comparison to healthy controls. SVM algorithms achieved 97% accuracy using the clustering coefficient as classifier derived from GM and 65% using WM from probabilistic tractography and 67% from modularity of FA maps to differentiate between CIS and RRMS patients. We demonstrate a clear increase of modular and local connectivity in patients with early RRMS in comparison to CIS and healthy subjects. Based only on a single anatomic scan and without a priori information, we developed an automated and investigator-independent paradigm that can accurately discriminate between patients with these clinically similar disease entities, and could thus complement the current dissemination-in-time criteria for clinical diagnosis.

Whole brain functional connectivity in clinically isolated syndrome without conventional brain MRI lesions

OBJECTIVE

To investigate brain functional connectivity (FC) alterations in patients with clinically isolated syndromes (CIS) presenting without conventional brain MRI lesions, and to identify the FC differences between the CIS patients who converted to multiple sclerosis (MS) and those not converted during a 5-year follow-up.

METHODS

We recruited 20 CIS patients without conventional brain lesions, 28 patients with MS and 28 healthy controls (HC). Normalized voxel-based functional connectivity strength (nFCS) was determined using resting-state fMRI (R-fMRI) and compared among groups. Furthermore, 5-years clinical follow-up of the CIS patients was performed to examine the differences in nFCS between converters and non-converters.

RESULTS

Compared to HC, CIS patients showed significantly decreased nFCS in the visual areas and increased nFCS in several brain regions predominately in the temporal lobes. MS patients revealed more widespread higher nFCS especially in deep grey matter (DGM), compared to CIS and HC. In the four CIS patients converting to MS, significantly higher nFCS was found in right anterior cingulate gyrus (ACC) and fusiform gyrus (FG), compared to non-converted patients.

CONCLUSION

We demonstrated both functional impairment and compensation in CIS by R-fMRI. nFCS alteration in ACC and FG seems to occur in CIS patients at risk of developing MS.

KEY POINTS

• Both functional impairment and compensation occur in CIS without conventional brain lesions. • MS patients revealed more widespread higher nFCS especially in deep grey matter. • nFCS alteration may help stratifying CIS at risk of developing MS.

Clinically Isolated Syndromes: Clinical Characteristics, Differential Diagnosis, and Management

Clinically isolated syndrome (CIS) is a term that describes the first clinical onset of potential multiple sclerosis (MS). The term CIS is typically applied to young adults with episodes of acute or subacute onset, which reaches a peak quite rapidly within 2-3 weeks. In 85% of young adults who develop MS, onset occurs with an acute, CIS of the optic nerves, brainstem, or spinal cord. When clinically silent brain lesions are seen on MRI, the likelihood of developing MS is high. Because no single clinical feature or diagnostic test is sufficient for the diagnosis of CIS, diagnostic criteria have included a combination of both clinical and paraclinical studies. Diagnostic criteria from the International Panel of McDonald and colleagues incorporate MRI evidence of dissemination in time and space to allow a diagnosis of definite MS in patients with CIS. As CIS is typically the earliest clinical expression of MS, research on patients with CIS may provide new insights into early pathological changes and pathogenetic mechanisms that might affect the course of the disorder. With recent improvements in diagnosis and the advent of disease-modifying treatments for MS, there has been growing interest and research in patients with CIS.

CSF Proteomics Identifies Specific and Shared Pathways for Multiple Sclerosis Clinical Subtypes

Multiple sclerosis (MS) is an immune-mediated, neuro-inflammatory, demyelinating and neurodegenerative disease of the central nervous system (CNS) with a heterogeneous clinical presentation and course. There is a remarkable phenotypic heterogeneity in MS, and the molecular mechanisms underlying it remain unknown. We aimed to investigate further the etiopathogenesis related molecular pathways in subclinical types of MS using proteomic and bioinformatics approaches in cerebrospinal fluids of patients with clinically isolated syndrome, relapsing remitting MS and progressive MS (n=179). Comparison of disease groups with controls revealed a total of 151 proteins that are differentially expressed in clinically different MS subtypes. KEGG analysis using PANOGA tool revealed the disease related pathways including aldosterone-regulated sodium reabsorption (p=8.02x10^-5) which is important in the immune cell migration, renin-angiotensin (p=6.88x10^-5) system that induces Th17 dependent immunity, notch signaling (p=1.83x10^-10) pathway indicating the activated remyelination and vitamin digestion and absorption pathways (p=1.73x10^-5). An emerging theme from our studies is that whilst all MS clinical forms share common biological pathways, there are also clinical subtypes specific and pathophysiology related pathways which may have further therapeutic implications.

The role of immune cells, glia and neurons in white and gray matter pathology in multiple sclerosis

Multiple sclerosis is one of the most common causes of chronic neurological disability beginning in early to middle adult life. Multiple sclerosis is idiopathic in nature, yet increasing correlative evidence supports a strong association between one's genetic predisposition, the environment and the immune system. Symptoms of multiple sclerosis have primarily been shown to result from a disruption in the integrity of myelinated tracts within the white matter of the central nervous system. However, recent research has also highlighted the hitherto underappreciated involvement of gray matter in multiple sclerosis disease pathophysiology, which may be especially relevant when considering the accumulation of irreversible damage and progressive disability. This review aims at providing a comprehensive overview of the interplay between inflammation, glial/neuronal damage and regeneration throughout the course of multiple sclerosis via the analysis of both white and gray matter lesional pathology. Further, we describe the common pathological mechanisms underlying both relapsing and progressive forms of multiple sclerosis, and analyze how current (as well as future) treatments may interact and/or interfere with its pathology. Understanding the putative mechanisms that drive disease pathogenesis will be key in helping to develop effective therapeutic strategies to prevent, mitigate, and treat the diverse morbidities associated with multiple sclerosis.

Predictive value of imaging markers at multiple sclerosis disease onset based on gadolinium- and USPIO-enhanced MRI and machine learning

OBJECTIVES

A novel characterization of Clinically Isolated Syndrome (CIS) patients according to lesion patterns is proposed. More specifically, patients are classified according to the nature of inflammatory lesions patterns. It is expected that this characterization can infer new prospective figures from the earliest imaging signs of Multiple Sclerosis (MS), since it can provide a classification of different types of lesions across patients.

METHODS

The method is based on a two-tiered classification. Initially, the spatio-temporal lesion patterns are classified. The discovered lesion patterns are then used to characterize groups of patients. The patient groups are validated using statistical measures and by correlations at 24-month follow-up with hypointense lesion loads.

RESULTS

The methodology identified 3 statistically significantly different clusters of lesion patterns showing p-values smaller than 0.01. Moreover, these patterns defined at baseline correlated with chronic hypointense lesion volumes by follow-up with an R(2) score of 0.90.

CONCLUSIONS

The proposed methodology is capable of identifying three major different lesion patterns that are heterogeneously present in patients, allowing a patient classification using only two MRI scans. This finding may lead to more accurate prognosis and thus to more suitable treatments at early stage of MS.

The diagnosis of multiple sclerosis and the various related demyelinating syndromes: a critical review

Multiple sclerosis (MS), is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function, that results from immune-mediated inflammation, demyelination and subsequent axonal damage. MS is one of the most common causes of neurological disability in young adults. Several variants of MS (and CNS demyelinating syndromes in general) have been nowadays defined in an effort to increase the diagnostic accuracy, to identify the unique immunopathogenic profile and to tailor treatment in each individual patient. These include the initial events of demyelination defined as clinically or radiologically isolated syndromes (CIS and RIS respectively), acute disseminated encephalomyelitis (ADEM) and its variants (acute hemorrhagic leukoencephalitis-AHL, Marburg variant, and Balo's concentric sclerosis), Schilder's sclerosis, transverse myelitis, neuromyelitis optica (NMO and NMO spectrum of diseases), recurrent isolated optic neuritis and tumefactive demyelination. The differentiation between them is not only a terminological matter but has important implications on their management. For instance, certain patients with MS and prominent immunopathogenetic involvement of B cells and autoantibodies, or with the neuromyelitic variants of demyelination, may not only not respond well but even deteriorate under some of the first-line treatments for MS. The unique clinical and neuroradiological features, along with the immunological biomarkers help to distinguish these cases from classical MS. The use of such immunological and imaging biomarkers, will not only improve the accuracy of diagnosis but also contribute to the identification of the patients with CIS or RIS who, are at greater risk for disability progression (worse prognosis) or, on the contrary, will have a more benign course. This review summarizes in a critical way, the diagnostic criteria (historical and updated) and the definitions/characteristics of MS of the various variants/subtypes of CNS demyelinating syndromes.

Regional MRI perfusion measures predict motor/executive function in patients with clinically isolated syndrome

Background. Patients with clinically isolated syndrome (CIS) demonstrate brain hemodynamic changes and also suffer from difficulties in processing speed, memory, and executive functions. Objective. To explore whether brain hemodynamic disturbances in CIS patients correlate with executive functions. Methods. Thirty CIS patients and forty-three healthy subjects, matched for age, gender, education level, and FSIQ, were administered tests of visuomotor learning and set shifting ability. Cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) values were estimated in normal-appearing white matter (NAWM) and normal-appearing deep gray Matter (NADGM) structures, using a perfusion MRI technique. Results. CIS patients showed significantly elevated reaction time (RT) on both tasks, while their CBV and MTT values were globally increased, probably due to inflammatory vasodilation. Significantly, positive correlation coefficients were found between error rates on the inhibition condition of the visuomotor learning task and CBV values in occipital, periventricular NAWM and both thalami. On the set shifting condition of the respective task significant, positive associations were found between error rates and CBV values in the semioval center and periventricular NAWM bilaterally. Conclusion. Impaired executive function in CIS patients correlated positively with elevated regional CBV values thought to reflect inflammatory processes.

A review of the anterior visual pathway model and the study of vitamin D in demyelinating disease

In recent years, theories about the anti-inflammatory properties of vitamin D in demyelinating disease have been well substantiated by human studies examining relapse reduction, MRI lesion activity and risk of MS conversion. However, the evidence that vitamin D may protect against neurodegeneration has not been established as of yet, and comes with the challenges of a manageable target over a manageable time period. Such challenges might be overcome by the anterior visual pathway (AVP) model of the central nervous system, which allows the non-invasive study (e.g. imaging, electrophysiology and clinical) of form and function within a much shorter time frame than pure clinical activity. This review outlines the state of current knowledge about vitamin D in demyelinating disease, and highlights the potential utility of using the AVP to study its neuroprotective effects.

The afferent visual pathway: designing a structural-functional paradigm of multiple sclerosis

Multiple sclerosis (MS) is a disease of the central nervous system (CNS) believed to arise from a dysfunctional immune-mediated response in a genetically susceptible host. The actual cause of MS is not known, and there is ongoing debate about whether this CNS disorder is predominantly an inflammatory versus a degenerative condition. The afferent visual pathway (AVP) is frequently involved in MS, such that one in every five individuals affected presents with acute optic neuritis (ON). As a functionally eloquent system, the AVP is amenable to interrogation with highly reliable and reproducible tests that can be used to define a structural-functional paradigm of CNS injury. The AVP has numerous unique advantages as a clinical model of MS. In this review, the parameters and merits of the AVP model are highlighted. Moreover, the roles the AVP model may play in elucidating mechanisms of brain injury and repair in MS are described.

Reports of patients and relatives from the CogniCIS study about cognition in clinically isolated syndrome: what are our patients telling us?

OBJECTIVE

To assess the Multiple Sclerosis Neuropsychological Questionnaire (MSNQ) in patients with clinically isolated syndrome (CIS).

METHODS

130 European CIS patients and 60 relatives completed the MSNQ.

RESULTS

The mean (SD) MSNQ score for CIS patients was 15.5 (10.8) and for their informants 11.3 (9.6). Neither the CIS patient nor relative MSNQ report scores correlated with any of the cognitive test scores in the Brief Repeatable Battery of Neuropsychological Tests, but they were significantly related to psychosocial scales including depression.

CONCLUSIONS

In CIS, patient and relative MSNQ scores are influenced by psychosocial variables rather than actual objective cognitive status. Formal cognitive test assessment is recommended for CIS patients.

Glatiramer acetate in treatment of multiple sclerosis: a toolbox of random co-polymers for targeting inflammatory mechanisms of both the innate and adaptive immune system?

Multiple sclerosis is a disease of the central nervous system, resulting in the demyelination of neurons, causing mild to severe symptoms. Several anti-inflammatory treatments now play a significant role in ameliorating the disease. Glatiramer acetate (GA) is a formulation of random polypeptide copolymers for the treatment of relapsing-remitting MS by limiting the frequency of attacks. While evidence suggests the influence of GA on inflammatory responses, the targeted molecular mechanisms remain poorly understood. Here, we review the multiple pharmacological modes-of-actions of glatiramer acetate in treatment of multiple sclerosis. We discuss in particular a newly discovered interaction between the leukocyte-expressed integrin α(M)β(2) (also called Mac-1, complement receptor 3, or CD11b/CD18) and perspectives on the GA co-polymers as an influence on the function of the innate immune system.

Quantitative T2' imaging in patients with clinically isolated syndrome

OBJECTIVE

The T2' imaging has been shown to be sensitive to oxygen saturation changes in normal appearing white and grey matter (NAWM, NAGM) in patients with relapsing-remitting multiple sclerosis (RRMS). We aimed to explore the presence and extent of T2' changes in patients with a clinically isolated syndrome (CIS) and a possible association of T2' with conventional magnetic resonance imaging and clinical outcomes.

MATERIAL AND METHODS

Quantitative T2- and T2*-weighted images were acquired in 32 treatment-naive patients with a CIS within 3 months of presentation and 15 age-matched healthy controls (HC). Quantitative T2' values were determined in six regions of interest (ROIs).

RESULTS

The T2' values in CIS did not differ significantly from those in HC. Among patients, T2' values correlated positively with the T2 lesion volume (T2LV, r = 0.34, P < 0.05). T2' values of the frontal NAWM correlated with the T2LV (r = 0.35, P < 0.05) and T2 lesion count (r = 0.4, P = 0.02).

CONCLUSION

As opposed to RRMS, patients with CIS did not show T2' alterations compared to HC. However, the association between the T2LV and higher T2' values suggests that T2' reflects disease evolution. In CIS metabolic changes might be masked by compensatory mechanisms and become overt when disease progresses as has been shown for RRMS patients.