Abnormal corpus callosum: a sensitive and specific indicator of multiple sclerosis

Ursolic Acid Enhances Myelin Repair in Adult Mice Brains and Stimulates Exhausted Oligodendrocyte Progenitors to Remyelinate

In multiple sclerosis patients, long-term inflammation makes the oligodendrocyte progenitor cells (OPCs) exhausted; therefore, a new therapy that makes them responsive to insults to participate in remyelination is highly in demand. Here, we investigated the effect of ursolic acid (UA) on myelin repair after mid-term and long-term demyelination periods induced by 6 or 12 weeks of cuprizone treatment followed by 2 weeks of recovery with or without UA. Immunohistochemistry studies and myelin genes expression assessment were used to evaluate the myelination status of mouse corpora callosa and the cellular mechanisms of myelin repair. Results showed that UA significantly promoted recovery from myelin loss after discontinuing 6 or 12 weeks of cuprizone feeding, as measured by luxol fast blue (LFB), fluoroMyelin (FM), anti-myelin basic protein (MBP) staining, and oligodendrocyte progenitor cell counts. It led to reduced inflammation and gliosis as evaluated by glial fibrillary acidic protein (GFAP), Iba1, or other marker gene transcripts. Following long-term demyelination, gliosis and TNF-α were observed as potential players in lesion pathology, which were restored by UA. An increased IL-10 may contribute to UA anti-inflammatory effect and making responsive the exhausted OPCs. UA increased the number of new oligodendrocyte lineage cells and myelination. Our findings indicated that UA can enhance myelin repair after cuprizone challenge through the prevention of gliosis and increasing the newly generated myelin.

Aging astrocytes metabolically support aging axon function by proficiently regulating astrocyte-neuron lactate shuttle

The astrocyte-neuron lactate shuttle (ANLS) is an essential metabolic support system that uptakes glucose, stores it as glycogen in astrocytes, and provides glycogen-derived lactate for axonal function. Aging intrinsically increases the vulnerability of white matter (WM) to injury. Therefore, we investigated the regulation of this shuttle to understand vascular-glial metabolic coupling to support axonal function during aging in two different WM tracts. Aging astrocytes displayed larger cell bodies and thicker horizontal processes in contrast to thinner vertically oriented processes of young astrocytes. Aging axons recovered less following aglycemia in mouse optic nerves (MONs) compared to young axons, although providing lactate during aglycemia equally supported young and aging axonal function. Incubating MONs in high glucose to upregulate glycogen stores in astrocytes delayed loss of function during aglycemia and improved recovery in both young and aging axons. Providing lactate during recovery from aglycemia unmasked a metabolic switch from glucose to lactate in aging axons. Young and aging corpus callosum consisting of a mixture of myelinated and unmyelinated axons sustained their function fully when lactate was available during aglycemia and surprisingly showed a greater resilience to aglycemia compared to fully myelinated axons of optic nerve. We conclude that lactate is a universal substrate for axons independent of their myelination content and age.

Single-cell profiling reveals periventricular CD56bright NK cell accumulation in multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease characterised by immune cell infiltration resulting in lesions that preferentially affect periventricular areas of the brain. Despite research efforts to define the role of various immune cells in MS pathogenesis, the focus has been on a few immune cell populations while full-spectrum analysis, encompassing others such as natural killer (NK) cells, has not been performed. Here, we used single-cell mass cytometry (CyTOF) to profile the immune landscape of brain periventricular areas – septum and choroid plexus – and of the circulation from donors with MS, dementia and controls without neurological disease. Using a 37-marker panel, we revealed the infiltration of T cells and antibody-secreting cells in periventricular brain regions and identified a novel NK cell signature specific to MS. CD56^bright NK cells were accumulated in the septum of MS donors and displayed an activated and migratory phenotype, similar to that of CD56^bright NK cells in the circulation. We validated this signature by multiplex immunohistochemistry and found that the number of NK cells with high expression of granzyme K, typical of the CD56^bright subset, was increased in both periventricular lesions and the choroid plexus of donors with MS. Together, our multi-tissue single-cell data shows that CD56^bright NK cells accumulate in the periventricular brain regions of MS patients, bringing NK cells back to the spotlight of MS pathology.

Neuroradiological differentiation of white matter lesions in patients with multiple sclerosis and Fabry disease

Objective

White matter lesions (WML) in multiple sclerosis (MS) differ from vascular WML caused by Fabry disease (FD). However, in atypical cases the discrimination can be difficult and may vary between individual raters. The aim of this study was to evaluate interrater reliability of WML differentiation between MS and FD patients.

Materials and methods

Brain MRI scans of 21 patients with genetically confirmed FD were compared to 21 matched patients with MS. Pseudonymized axial FLAIR sequences were assessed by 6 blinded raters and attributed to either the MS or the FD group to investigate interrater reliability. Additionally, localization of WML was compared between the two groups.

Results

The median age of patients was 46 years (IQR 35–58). Interrater reliability was moderate with a Fleiss' Kappa of 0.45 (95%CI 0.3–0.59). Overall, 85% of all ratings in the MS group and 75% in the FD group were correct. However, only 38% of patients with MS and 33% of patients with FD were correctly identified by all 6 raters. WML involving the corpus callosum (p < 0.001) as well as juxtacortical (p < 0.001) and infratentorial lesions (p = 0.03) were more frequently observed in MS patients.

Conclusion

Interrater reliability regarding visual differentiation of WML in MS from vascular WML in FD on standard axial FLAIR images alone is only moderate, despite the distinctive features of lesions in each group.

Behavioural and histological changes in cuprizone-fed mice

Feeding cuprizone (CPZ) to mice causes demyelination and reactive gliosis in the central nervous system (CNS), hallmarks of some neurodegenerative diseases like multiple sclerosis. However, relatively little is known regarding the behavioural deficits associated with CPZ-feeding and much of what is known is contradictory. This study investigated whether 37 days oral feeding of 0.2% CPZ to young adult mice evoked sensorimotor behavioural changes. Behavioural tests included measurements of nociceptive withdrawal reflex responses and locomotor tests. Additionally, these were compared to histological analysis of the relevant CNS regions by analysis of neuronal and glial cell components. CPZ-fed mice exhibited more foot slips in walking ladder and beam tests compared to controls. In contrast, no changes in nociceptive thresholds to thermal or mechanical stimuli occurred between groups. Histological analysis showed demyelination throughout the CNS, which was most prominent in white matter tracts in the cerebrum but was also elevated in areas such as the hippocampus, basal ganglia and diencephalon. Profound demyelination and gliosis was seen in the deep cerebellar nuclei and brain stem regions associated with the vestibular system. However, in the spinal cord changes were minimal. No loss of oligodendrocytes, neurons or motoneurons occurred but a significant increase in astrocyte staining ensued throughout the white matter of the spinal cord. The results suggest that CPZ differentially affects oligodendrocytes throughout the CNS and induces subtle motor changes such as ataxia. This is associated with deficits in CNS regions associated with motor and balance functions such as the cerebellum and brain stem.

Multiple Sclerosis in the Emirati Population: Onset Disease Characterization by MR Imaging

Background and Objectives

Multiple Sclerosis (MS) epidemiology is on the path of globalization mainly due to changing environmental factors. The prevalence of MS is on the rise in the Middle East and Persian Gulf region. Our observations has led us to hypothesize a heavy MRI lesion load at the onset of disease in a relatively younger native population. We aimed to estimate and characterize the onset disease on MRI using McDonald's criteria while applying its terms of “Dissemination in Space (DIS) and Dissemination in Time (DIT)”.

Materials and Methods

Retrospective review of onset MRI studies of 181 Emirati (native) individuals. Basic demographics were captured. Only 47 patients with Clinically Definite MS (CDMS) were included who had onset diagnostic MRI available. Lesion load was quantified using the specific zones of involvement designated for DIS: (1) Periventricular (PVZ) (I), (2) Juxta-cortical (II) (3) Infra-tentorial (III) and, (4) Spinal cord (IV). PVZ was sub-classified and lesions were quantified. A single enhancing lesion was required for DIT.

Results

Average age of onset was about 26 years with female dominance of about 2 : 1. About 50% had all 4 zones and about 85% had at least 3 zones involved at the onset. Involvement of only 1 zone was rare. Dissemination in time (DIT) in brain and/or cord was present in approximately 50%. Each of the 4 zones were involved in at least 70% of cases. PVZ was not spared in any case with at least 3 lesions present in approx. 95% and ≥12 lesions in approx. half of the patients. Spinal cord specifically cervical cord was involved in up to 80% with typical patchy lesions.

Conclusion

Onset disease characterization using MRI in a young Emirati cohort showed a heavy lesion load in the brain and spinal cord at the onset, signifying cumulative disease before presentation. Disseminated disease also facilitated early diagnosis of MS. The findings have significant potential ramifications for local environmental and cultural factors, as well as disease course and disability progression.

The Relationship between Corpus Callosum Morphometric Measurements and Age/Gender Characteristics: A Comprehensive MR Imaging Study

Objective

The objective of the study was to examine a possible relationship between morphometric corpus callosum (CC) measurements, age, and gender characteristics using MR images.

Materials and Methods

The medical data and MR examinations of 436 consecutive subjects were retrospectively reviewed. The CC thickness from five different sites, and additionally splenium length, height, and total length of the CC, and the splenium index (SI) were measured with a mid-sagittal T1-weighted sequence. Those measurements were compared with age and gender characteristics.

Results

A weak but statistically significant negative correlation was found between age and thicknesses of genu and all body portions of CC (P = ≤0.001 for all, r = -0.32 for genu, r = -0.317 for B1, r = -0.328 for B2, r = -0.328 for B2, and r = -0.194 for B3 and B4). There was a weak but statistically significant positive correlation between age and the lengths of CC and splenium (P ≤ 0.022 for both, r = 0.112 for CC length and r = 0.11 for splenium length). The second part of the body (B2) was thicker in females (P = 0.014). On the other hand, the CC and splenium lengths were greater in males compared to females (P = 0.029 for both).

Conclusion

We designed a comprehensive MRI study to investigate a possible relationship between normal morphometric CC measurements in 436 healthy subjects. We preferred splenium length and SI as the main splenium measurements instead of direct splenium thickness, due to discrepancies regarding splenium measurement methods in the medical literature. There was a wide spectrum of results, and we compared those results with existing medical literature.

Phase II Randomized Controlled Trial of Constraint-Induced Movement Therapy in Multiple Sclerosis. Part 2: Effect on White Matter Integrity

BACKGROUND

Constraint-induced movement therapy (CIMT) is a method of physical rehabilitation that has demonstrated clinical efficacy in patients with chronic stroke, cerebral palsy, and multiple sclerosis (MS).

OBJECTIVE

This pilot randomized controlled trial tested whether CIMT can also induce increases in white matter integrity in patients with MS.

METHODS

Twenty adults with chronic hemiparetic MS were randomized to receive either CIMT or complementary and alternative medicine (CAM) treatment (reported in the first article of this pair). Structural white matter change was assessed by tract-based spatial statistics (TBSS); measures included fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD).

RESULTS

CIMT and CAM groups did not differ in pretreatment disability or expectancy to benefit. As noted in the companion paper, the motor activity log (MAL) improved more after CIMT than CAM ( P < .001); the within-group effect size for CIMT was 3.7 (large d' = 0.57), while for CAM it was just 0.7. Improvements in white matter integrity followed CIMT and were observed in the contralateral corpus callosum (FA, P < .05), ipsilateral superior occipital gyrus (AD, P < .05), ipsilateral superior temporal gyrus (FA, P < .05), and contralateral corticospinal tract (MD and RD, P < .05).

CONCLUSION

CIMT produced a very large improvement in real-world limb use and induced white matter changes in patients with hemiparetic MS when compared with CAM. The findings suggest in preliminary fashion that the adverse changes in white matter integrity induced by MS might be reversed by CIMT.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT01081275).

Misdiagnosis of multiple sclerosis: Impact of the 2017 McDonald criteria on clinical practice

Misdiagnosis of multiple sclerosis (MS) (the incorrect assignment of a diagnosis of MS) remains a problem in contemporary clinical practice. Studies indicate that misdiagnosed patients are often exposed to prolonged unnecessary health care risks and morbidity. The recently published 2017 revision of the McDonald criteria for the diagnosis of MS provides an opportunity to consider the effect of these revisions on the problem of MS misdiagnosis. The 2017 McDonald criteria include several new recommendations to reduce potential for misdiagnoses. The criteria should be used for the types of patients in which validation studies were performed, specifically those patients who present with typical demyelinating syndromes. MRI lesion characteristics were defined for which McDonald criteria would be expected to perform with accuracy. However, 2017 revisions, which now include assessment for cortical lesions, and the inclusion of symptomatic lesions and positive oligoclonal bands for the fulfillment of diagnostic criteria, may have the potential to lead to misdiagnosis of MS if not applied appropriately. While the 2017 McDonald criteria integrate issues relating to MS misdiagnosis and incorporate specific recommendations for its prevention more prominently than prior criteria, the interpretation of clinical and radiologic assessments upon which these criteria depend will continue to allow misdiagnoses. In patients with atypical clinical presentations, the revised McDonald criteria may not be readily applied. In those situations, further evaluation or monitoring rather than immediate diagnosis of MS is prudent.

Combined structural and functional patterns discriminating upper limb motor disability in multiple sclerosis using multivariate approaches

A structural or functional pattern of neuroplasticity that could systematically discriminate between people with impaired and preserved motor performance could help us to understand the brain networks contributing to preservation or compensation of behavior in multiple sclerosis (MS). This study aimed to (1) investigate whether a machine learning-based technique could accurately classify MS participants into groups defined by upper extremity function (i.e. motor function preserved (MP) vs. motor function impaired (MI)) based on their regional grey matter measures (GMM, cortical thickness and deep grey matter volume) and inter-regional functional connection (FC), (2) investigate which features (GMM, FC, or GMM + FC) could classify groups more accurately, and (3) identify the multivariate patterns of GMM and FCs that are most discriminative between MP and MI participants, and between each of these groups and the healthy controls (HCs). With 26 MP, 25 MI, and 21 HCs (age and sex matched) underwent T1-weighted and resting-state functional MRI at 3 T, we applied support vector machine (SVM) based classification to learn discriminant functions indicating regions in which GMM or between which FCs were most discriminative between groups. This study demonstrates that there exist structural and FC patterns sufficient for correct classification of upper limb motor ability of people with MS. The classifier with GMM + FC features yielded the highest accuracy of 85.61 % (p < 0.001) to distinguish between the MS groups using leave-one-out cross-validation. It suggests that a machine-learning approach combining structural and functional features is useful for identifying the specific neural substrates that are necessary and sufficient to preserve motor function among people with MS.

A Rational Design of a Selective Inhibitor for Kv1.1 Channels Prevalent in Demyelinated Nerves That Improves Their Impaired Axonal Conduction

K⁺ channels containing Kv1.1 α subunits, which become prevalent at internodes in demyelinated axons, may underlie their dysfunctional conduction akin to muscle weakness in multiple sclerosis. Small inhibitors were sought with selectivity for the culpable hyper-polarizing K⁺ currents. Modeling of interactions with the extracellular pore in a Kv1.1-deduced structure identified diaryldi(2-pyrrolyl)methane as a suitable scaffold with optimized alkyl ammonium side chains. The resultant synthesized candidate [2,2'-((5,5'(di-p-topyldiaryldi(2-pyrrolyl)methane)bis(2,2'carbonyl)bis(azanediyl)) diethaneamine·2HCl] (8) selectively blocked Kv1.1 channels (IC₅₀ ≈ 15 μM) recombinantly expressed in mammalian cells, induced a positive shift in the voltage dependency of K⁺ current activation, and slowed its kinetics. It preferentially inhibited channels containing two or more Kv1.1 subunits regardless of their positioning in concatenated tetramers. In slices of corpus callosum from mice subjected to a demyelination protocol, this novel inhibitor improved neuronal conduction, highlighting its potential for alleviating symptoms in multiple sclerosis.

The Corpus Callosum and Forensic Issues-An Overview

The corpus callosum is a large central white matter tract that connects the right and left cerebral hemispheres. It permits placental mammals to have a more sophisticated interhemispheric integration of sensory cortices and allows communication between cortical and subcortical neurons. Search of the literature and the pathology archives at The University of Adelaide was undertaken to identify lesions and injuries within the corpus callosum that may have forensic significance. These include developmental/congenital lesions with agenesis/dysgenesis, vascular malformations, and lipomas; inherited syndromes such as neurofibromatosis; and acquired lesions involving trauma, neoplasia, demyelination, vascular conditions, infections, fat embolism, aging/dementia, and the effects of toxins. The finding of lesions within the corpus callosum should initiate careful examination of the adjacent brain and other organ systems for related phenomena as this may shed some light on the nature of the underlying condition, and also help to determine whether there are any forensic implications.

MRI/MRS of corpus callosum in patients with clinically isolated syndrome suggestive of multiple sclerosis

A trophy of corpus callosum (C C) related to axonal loss has previously been observed in patients at the early stage of clinically definite multiple sclerosis (CDMS). Atrophy increases with the progression of the disease. Nevertheless, no data concerning the onset of atrophy of C C are currently available. The purpose of this study is to determine if damage in callosal tissue was present at the earliest stage of MS, in a subgroup of patients presenting with a clinically isolated syndrome suggestive of MS (C ISSMS), fulfilling the dissemination in space criteria according to McDonald. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) techniques were applied to measure C C volume, magnetization transfer ratio (MTR), mean diffusivity (MD), N-acetyl aspartate/choline-containing compounds (NAA/C ho) ratio, N-acetyl aspartate/total creatine (NA A/C r) ratio and C ho/C r ratio inside the C C of 46 C ISSMS patients and 24 sexand age-matched controls. No atrophy of C C was observed in the C ISSMS group. C C of patients was character ized by decreased MTR and increased MD. No change in the NA A/C r ratio was observed while the NA A/C ho ratio decreased and C ho/C r ratio increased in the splenium and the central anterio r part of C C. These abnormalities were present in patients with, but also without, macroscopic lesions inside the C C. O ur results indicate that diffuse structural and metabolic changes, which may be interpreted as representing predominantly myelin patho logy, occur in the C C at the earliest stage of MS before any atrophy is detected.

Magnetic resonance imaging of optic nerve

Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI), plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies.

Systematic imaging review: Multiple Sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory disease of the central nervous system characterised by immune-mediated demyelination, and is a leading cause of neurological disability worldwide. It has a wide spectrum of clinical presentations which overlap with other neurological conditions many times. Further, the radiological array of findings in MS can also be confused for multiple other conditions, leading to the need to look for the more typical findings, and interpret these in close conjunction with the clinical picture including temporal evolution. This review aims to revisit the MRI findings in MS, including recent innovations in imaging, and to help distinguish MS from its mimics.

Gadolinium-Enhancing Lesions Lead to Decreases in White Matter Tract Fractional Anisotropy in Multiple Sclerosis

PURPOSE

Although MRI identification of new lesions forms the basis for monitoring disease progression in multiple sclerosis patients, how lesion activity relates to longitudinal white matter changes in the brain is unknown. We hypothesized that patients with gadolinium-enhancing lesions would show greater longitudinal decline in fractional anisotropy in major tracts compared to those with stable disease.

METHODS

Thirty patients with relapsing-remitting multiple sclerosis were included in this study-13 had enhancing lesions at baseline and 17 did not. Each patient underwent at least two 3 Tesla contrast-enhanced MRI scans with a DTI sequence with a median interval of 2.1 years between scans. The forceps major and minor of the corpus callosum and the bilateral corticospinal tracts were selected as the major white matter tracts of interest. These tracts were reconstructed using region-of-interest placement on standard anatomical landmarks and a fiber assignment by continuous tracking algorithm using TrackVis (version 0.5.2.2) software. Mixed-effects regression models were used to determine the association between enhancing lesions and subsequent longitudinal change in fractional anisotropy.

RESULTS

In patients with enhancing lesions, there was greater decline in fractional anisotropy compared to those with stable disease in the forceps major (P = .026), right corticospinal tract (P = .032), and marginally in the left corticospinal tract (P = .050), but not the forceps minor (P = .11).

CONCLUSION

Fractional anisotropy of major white matter tracts declined more rapidly in patients with enhancing lesions, suggesting greater diffuse white matter injury with active inflammatory disease. DTI may provide a means of monitoring white matter injury following relapses.

Proteomics of a conundrum: Thoughts on addressing the aetiology versus progression of multiple sclerosis

Currently in the field of multiple sclerosis (MS) research there is an ongoing debate concerning the cause of the disease. MS is widely considered to begin with an autoimmune dysregulation. The disease does have a prominent autoimmune component however this may be representative of a secondary effect. There is growing evidence that the disease may be initiated by an underlying degeneration of oligodendrocytes. In our viewpoint, we discuss the potential differences between the aetiology and progression of MS. For the most part, proteomic analysis has focused on the autoimmune component of the disease. We suggest that proteomic analysis should be applied to investigating oligodendrocyte degeneration. We discuss the potential of the cuprizone animal model of demyelination and its usefulness in understanding oligodendrocyte degeneration. Immune suppressive therapies are effective at reducing clinical symptoms and improving quality of life. However, a cure is still lacking and as such the disease does still progress. We suggest that if the initiating cause is poorly understood, then curing MS is unlikely.

Fabry disease mimicking multiple sclerosis: Lessons from two case reports

Fabry disease is an X-linked lysosomal storage disorder that can mimic multiple sclerosis. We present two cases of heterozygous adult women where clinical and radiological features initially suggested a diagnosis of multiple sclerosis. This led us to review the early clinical course and neurological features of Fabry disease and highlight the importance of assessing non-neurologic (systemic) symptoms when considering a diagnosis of multiple sclerosis and the need for specialist interpretation of neuroradiological findings.

Magnetic Resonance Imaging of Asians with Multiple Sclerosis was Similar to that of the West

Magnetic resonance imaging (MRI) of the brain is the most important paraclinical diagnostic test in multiple sclerosis (MS). The appearance of MRI in Asians with MS is not well defined. We retrospectively surveyed the first brain and spinal cord MRI in patients diagnosed to have MS, according to Poser's criteria in seven regions throughout Asia to define the MRI changes among Asians with MS. There were 101 patients with first brain, and 86 with first spinal cord MRI, 66 of whom had both. The brain MRI showed a mean of 17 lesions per patient in T2 weighted images, mostly asymptomatic. Almost all the lesions were in the white matter, particularly in the juxtacortical, deep and periventricular white matter. A third of the lesions were greater than 5 mm, 14% enhanced with gadolinium. There were more supratentorial than infratentorial lesions at a ratio of 7.5: 1. Ninety five percent of the spinal cord lesions were in cervical and thoracic regions, 34% enhanced with gadolinium. The lesions extended over a mean of 3.6 +/- 3.3 vertebral bodies in length. Fifty (50%) of the brain and 54 (63%) of the spinal MRI patients had the optic-spinal form of MS. The MRI of the optic-spinal and classical groups of patients were similar in appearance and distribution, except that the optic-spinal MS patients have fewer brain but longer and more severe spinal cord lesions. In conclusion, the brain and spinal cord MRI of Asian patients with MS was similar to that of the West, although, in this study, Asian MS patients had larger spinal cord lesions.

The relationship between regional microstructural abnormalities of the corpus callosum and physical and cognitive disability in relapsing-remitting multiple sclerosis

Significant corpus callosum (CC) involvement has been found in relapsing–remitting multiple sclerosis (RRMS), even if conventional magnetic resonance imaging measures have shown poor correlation with clinical disability measures. In this work, we tested the potential of multimodal imaging of the entire CC to explain physical and cognitive disability in 47 patients with RRMS. Values of thickness, fractional anisotropy (FA) and mean diffusivity (MD) were extracted from 50 regions of interest (ROIs) sampled along the bundle. The relationships between clinical, neuropsychological and imaging variables were assessed by using Spearman's correlation. Multiple linear regression analysis was employed in order to identify the relative importance of imaging metrics in modeling different clinical variables. Regional fiber composition of the CC differentially explained the response variables (Expanded Disability Status Scale [EDSS], cognitive impairment). Increases in EDSS were explained by reductions in CC thickness and MD. Cognitive impairment was mainly explained by FA reductions in the genu and splenium. Regional CC imaging properties differentially explained disability within RRMS patients revealing strong, distinct patterns of correlation with clinical and cognitive status of patients affected by this specific clinical phenotype.

•

We assess corpus callosum damage in relapsing–remitting multiple sclerosis.

•

We used no a priori subdivisions to model the bundle in a continuous fashion.

•

Imaging–clinical relationship was explored by correlation and regression analyses.

•

Damage of large, heavily myelinated axons was mainly linked to physical disability.

•

Damage of small-diameter axons was mainly linked to cognitive impairment.

Establishment and characterization of an optimized mouse model of multiple sclerosis-induced neuropathic pain using behavioral, pharmacologic, histologic and immunohistochemical methods

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) that causes debilitating central neuropathic pain in many patients. Although mouse models of experimental autoimmune encephalomyelitis (EAE) have provided insight on the pathobiology of MS-induced neuropathic pain, concurrent severe motor impairments confound quantitative assessment of pain behaviors over the disease course. To address this issue, we have established and characterized an optimized EAE-mouse model of MS-induced neuropathic pain. Briefly, C57BL/6 mice were immunized with MOG35-55 (200μg) and adjuvants comprising Quil A (45μg) and pertussis toxin (2×250ng). The traditionally used Freund's Complete Adjuvant (FCA) was replaced with Quil A, as FCA itself induces CNS neuroinflammation. Herein, EAE-mice exhibited a mild relapsing-remitting clinical disease course with temporal development of mechanical allodynia in the bilateral hindpaws. Mechanical allodynia was fully developed by 28-30days post-immunization (p.i.) and was maintained until study completion (52-60days p.i.), in the absence of confounding motor deficits. Single bolus doses of amitriptyline (1-7mg/kg), gabapentin (10-50mg/kg) and morphine (0.1-2mg/kg) evoked dose-dependent analgesia in the bilateral hindpaws of EAE-mice; the corresponding ED50s were 1.5, 20 and 1mg/kg respectively. At day 39 p.i. in EAE-mice exhibiting mechanical allodynia in the hindpaws, there was marked demyelination and gliosis in the brain and lumbar spinal cord, mirroring these pathobiologic hallmark features of MS in humans. Our optimized EAE-mouse model of MS-associated neuropathic pain will be invaluable for future investigation of the pathobiology of MS-induced neuropathic pain and for efficacy profiling of novel molecules as potential new analgesics for improved relief of this condition.

Diagnosis and differential diagnosis of multiple sclerosis

PURPOSE OF REVIEW

When a patient presents with symptoms or imaging suggestive of multiple sclerosis (MS), making the correct diagnosis may at times be straightforward but in many cases is quite challenging. Symptoms may be difficult for patients to characterize and for clinicians to interpret; findings on examination may be subtle; imaging is not always specific; and the differential diagnosis of possible demyelinating disease is quite broad. Making a correct diagnosis of MS early in the disease course is likely to become even more important over time as new disease-modifying therapies, particularly those with potential neuroprotective benefits, are introduced. This article reviews the current diagnostic criteria for MS and illustrates their application as well as reviews the differential diagnosis for patients presenting with symptoms or imaging suggestive of demyelinating disease.

RECENT FINDINGS

The diagnostic criteria for MS were revised by the International Panel on Diagnosis of Multiple Sclerosis in 2010.

SUMMARY

The diagnostic criteria for MS have been revised several times over the years, most recently giving rise to the McDonald 2010 criteria. The diagnosis of MS begins with a patient who presents with symptoms typical for the disease, termed the "clinically isolated syndrome," which most commonly affects the optic nerves, brainstem, or spinal cord. If the patient's symptoms and imaging are typical for MS, the clinician can then apply the appropriate diagnostic criteria. If atypical clinical or imaging findings are present, alternative etiologies must be pursued as appropriate.

MRI mimics of multiple sclerosis

Diagnosis of multiple sclerosis (MS) is based on the demonstration of dissemination of lesions in space (DIS) and in time (DIT), as well as on the exclusion of an alternative neurologic disorder. As a paraclinical tool brain and/or spinal cord magnetic resonance imaging (MRI), showing typical lesion morphology, characteristic distribution of lesions, or involvement or specific anatomic structures, can support the diagnosis of MS. But from an imaging perspective a considerable amount of inherited and acquired disorders may manifest with radiologic evidence of DIT, DIS, or both. Hypoxic-ischemic vasculopathy, specially small-vessel disease, inflammatory disorders, vasculitis, and non-MS idiopathic inflammatory disorders, as well as some toxic, metabolic, and infectious disorders, may present mimicking MS on MR examinations and should be included in the differential diagnosis of MS-like lesions. Careful evaluation of associated findings on MRI, the so-called MRI red flags, such as the presence of infarcts, microbleeds, meningeal enhancement, and calcifications among others, are very helpful in suggesting a diagnosis other than MS. Complement MRI findings to patient's history, demographics, and serologic findings are crucial to achieve the correct diagnosis. We will review the most frequent radiologic appearance and differential features from the most frequent MS mimickers.

MRI evaluation of pathologies affecting the corpus callosum: A pictorial essay

The corpus callosum is a midline cerebral structure and has a unique embryological development pattern. In this article, we describe the pathophysiology and present imaging findings of various typical/atypical conditions affecting the corpus callosum. Since many of these pathologies have characteristic appearances on magnetic resonance imaging (MRI) and their therapeutic approaches are poles apart, ranging from medical to surgical, the neuroradiologist should be well aware of them.

Updates on clinically isolated syndrome and diagnostic criteria for multiple sclerosis

Clinically isolated syndrome (CIS) is a central nervous system demyelinating event isolated in time that is compatible with the possible future development of multiple sclerosis (MS). Early risk stratification for conversion to MS helps with treatment decisions. Magnetic resonance imaging (MRI) is currently the most useful tool to evaluate risk. Cerebrospinal fluid studies and evoked potentials may also be used to assess the likelihood of MS. Four clinical trials evaluating the benefits of either interferon β (IFN-β) or glatiramer acetate (GA) within the first 3 months after a high-risk CIS demonstrate decreased rates of conversion to clinically definite MS (CDMS) and a lesser degree of MRI progression with early treatment. In the 3-, 5-, and 10-year extension studies of 2 formulations of IFN-β, the decreased conversion rate to CDMS remained meaningful when comparing early treatment of CIS to treatment delayed by a median of 2 to 3 years. Diagnostic criteria have been developed based on the clinical and MRI follow-up of large cohorts with CIS and provide guidance on how to utilize clinical activity in combination with radiographic information to diagnose MS. The most recent 2010 McDonald criteria simplify requirements for dissemination in time and space and allow for diagnosis of MS from a baseline brain MRI if there are both silent gadolinium-enhancing lesions and nonenhancing lesions on the same imaging study. The diagnostic criteria for MS require special consideration in children at risk for acute disseminated encephalomyelitis (ADEM), in older adults who may have small vessel ischemic disease, and in ethnic groups that more commonly develop neuromyelitis optica (NMO).

Neuroradiological evaluation of demyelinating disease

Central nervous system inflammatory demyelinating disease can affect patients across the life span. Consensus definitions and criteria of all of the different acquired demyelinating diseases that fall on this spectrum have magnetic resonance imaging criteria. The advances of both neuroimaging techniques and important discoveries in immunology have produced an improved understanding of these conditions and classification. Neuroimaging plays a central role in the accurate diagnosis, prognosis, disease monitoring and research efforts that are being undertaken in this disease. This review focuses on the imaging spectrum of acquired demyelinating disease.

Superficial brain stimulation in multiple sclerosis

Central motor conduction time (CMCT) is the most frequently studied measure derived from transcranial magnetic stimulation (TMS) in multiple sclerosis (MS); it is abnormal in 57-93% of patients. Addition of the triple stimulation technique and combining motor with other evoked potentials (EPs) increases sensitivity. Cross-sectional correlations of TMS measures with clinical assessments of motor dysfunction or global disability are high. Longitudinally, CMCT is sensitive to both worsening and improvement of motor function, showing its potential to detect therapeutic responses. Moreover, combined multimodal EPs are valid quantitative predictors of the clinical course over periods ranging from 2 to 14 years. Measures of transcallosal connectivity (ipsilateral silent period and interhemispheric inhibition) are altered even in early MS, and yield complementary information on subclinical changes. Pathological brain plasticity in MS has been demonstrated by paired associative stimulation studies revealing a compensatory role of the ipsilateral motor and premotor areas. Central motor fatigue is associated with reduced motor EP amplitudes and increased cortical silent periods in normal controls, whereas patients with MS suffering from subjective fatigue show various abnormalities in cortical modulation of the motor system.

Diffuse and heterogeneous T2-hyperintense lesions in the splenium are characteristic of neuromyelitis optica

Background:

Callosal lesions in multiple sclerosis (MS) are usually focal, involving the inferior aspect of the corpus callosum on brain magnetic resonance imaging (MRI), but little is known about callosal lesions in neuromyelitis optica (NMO).

Objective:

To clarify MRI abnormalities in callosal lesions of NMO.

Methods:

Japanese patients with NMO ( n=28) or MS ( n=22) were assessed. The distributions and appearances of callosal lesions were evaluated on a brain mid-sagittal T2-weighted image (T2WI) or a fluid-attenuated inversion recovery image with a 1.5T MRI scanner. Logistic regression analysis identified which characteristics of the callosal lesions were useful for discriminating NMO from MS.

Results:

Callosal lesions were present in 79% of NMO and 82% of MS patients. Callosal abnormalities of NMO, including splenial lesions (57% in NMO versus 27% in MS, odds ratio (OR)=4.23, p=0.04), diffusely spreading lesions from the lower to upper edges of the corpus callosum (71% versus 23%, OR=7.18, p=0.0024), and heterogeneous T2 hyperintense lesions (71% versus 9%, OR=44.3, p=0.0006), were feasible for discriminating NMO from MS.

Conclusion:

Diffuse and heterogeneous T2 hyperintense splenial lesions were characteristic of NMO. These findings could help distinguish NMO from MS on MRI.

Classifying minimally disabled multiple sclerosis patients from resting state functional connectivity

Multiple sclerosis (MS), a variable and diffuse disease affecting white and gray matter, is known to cause functional connectivity anomalies in patients. However, related studies published to-date are post hoc; our hypothesis was that such alterations could discriminate between patients and healthy controls in a predictive setting, laying the groundwork for imaging-based prognosis. Using functional magnetic resonance imaging resting state data of 22 minimally disabled MS patients and 14 controls, we developed a predictive model of connectivity alterations in MS: a whole-brain connectivity matrix was built for each subject from the slow oscillations (<0.11 Hz) of region-averaged time series, and a pattern recognition technique was used to learn a discriminant function indicating which particular functional connections are most affected by disease. Classification performance using strict cross-validation yielded a sensitivity of 82% (above chance at p<0.005) and specificity of 86% (p<0.01) to distinguish between MS patients and controls. The most discriminative connectivity changes were found in subcortical and temporal regions, and contralateral connections were more discriminative than ipsilateral connections. The pattern of decreased discriminative connections can be summarized post hoc in an index that correlates positively (ρ=0.61) with white matter lesion load, possibly indicating functional reorganisation to cope with increasing lesion load. These results are consistent with a subtle but widespread impact of lesions in white matter and in gray matter structures serving as high-level integrative hubs. These findings suggest that predictive models of resting state fMRI can reveal specific anomalies due to MS with high sensitivity and specificity, potentially leading to new non-invasive markers.

Demyelination and remyelination in anatomically distinct regions of the corpus callosum following cuprizone intoxication

Multiple sclerosis is a chronic demyelinating disease of the central nervous system. Spontaneous remyelination during early disease stages is thought to preserve and partially restore function. However, this process ceases in later stages despite the presence of pre-oligodendrocytes. Cuprizone-induced demyelination is a useful model with which to study the remyelination process. Previous studies have demonstrated heterogeneities in demyelination in individual animals. Here we investigated regional differences in demyelination and remyelination within the corpus callosum. C57BL/6 mice were fed 0.2% cuprizone for 5 weeks to induce demyelination. Remyelination was examined 2-5 weeks after cuprizone withdrawal. Immunohistochemistry and electron microscopy were used to quantify regional differences in demyelination, gliosis, and remyelination. We found that, while demyelination was limited in the rostral region of corpus callosum, nearly complete demyelination occurred in the caudal callosum, beginning at approximately -0.5mm from bregma. Astrogliosis and microgliosis were correlated with demyelination and differed between the rostral and caudal callosal structures. Remyelination upon cessation of cuprizone ensued at different rates with splenium remyelinating faster than dorsal hippocampal commissure. Our data show anatomical differences of cuprizone-induced demyelination and remyelination in the corpus callosum and the importance of examining specific callosal regions in myelin repair studies using this model.

Corpus callosum microstructural changes correlate with cognitive dysfunction in early stages of relapsing-remitting multiple sclerosis: axial and radial diffusivities approach

The corpus callosum is the largest fiber bundle in the central nervous system and it takes part in several cognitive pathways. It can be affected by multiple sclerosis (MS) early in the disease. DTI is capable of infering the microstructural organization of the white matter. The vectorial analysis of the DTI offers the more specific indices of axial diffusivity (AD) and radial diffusivity (RD), which have shown to be useful to discriminate myelin damage from axon loss, respectively. This study presents DTI results (mean diffusivity (MD), fractional anisotropy (FA), RD, and AD) of 23 relapsing-remitting MS patients and its correlation with cognitive performance. There were 47.8% of cognitive impaired patients (MS CI). We found signs of demyelination, reflected by increased RD, and incipient axon loss, reflected by AD increase, which was slightly higher in the MS CI. The cognitive changes correlated with the DTI parameters, suggesting that loss of complexity in CC connections can impair neural conduction. Thus, cognitive impairment can be related to callosal disconnection, and DTI can be a promising tool to evaluate those changes.

Brain single photon emission computed tomography with Tc-99m MIBI or Tc-99m ECD in comparison to MRI in multiple sclerosis

PURPOSE

To evaluate whether or not brain single photon emission computed tomography (SPECT) with Tc-99m MIBI or Tc-99m ECD (ethyl cysteinate dimer) can detect any abnormality in patients with definite multiple sclerosis (MS). We then compared these values with the results of T1, T2, and fluid-attenuated inversion recovery in magnetic resonance imaging (MRI).

MATERIALS AND METHODS

A total of 16 patients with proved MS were enrolled in the study, and the MRI with and without gadolinium contrast and also brain SPECT with Tc-99m MIBI (8 cases) or Tc-99m ECD (8 other cases) were performed.

RESULTS

MRI studies was performed in 16 patients (13 women and 3 men, aged 16-38 years) and an average of 10.47, 3.7, 5.3, 1.7, and 0.9 lesions was found in respect in periventricular white matter, juxtacortical white matter, corpus callosum, cerebellar peduncles, and brainstem, whereas brain SPECT with Tc-99m MIBI or Tc-99m ECD detected no abnormality. In addition, 6 cases had some degree of contrast enhancement.

CONCLUSIONS

It seems that brain SPECT with Tc-99m MIBI or Tc-99m ECD would not improve this insufficiency. The small sizes of some plaques, particularly in chronic atrophic form of lesions, and the possibility of deeper anatomic positions of plaques can explain to some extent why the MS lesions were impossible to delineate on brain scan, although additional studies are needed.

Diffusion tensor group tractography of the corpus callosum in clinically isolated syndrome

BACKGROUND AND PURPOSE

Many studies have observed atrophy and abnormal diffusion within the CC in MS. However, few studies have addressed whether such abnormalities appear at the earliest stage of MS, especially in CIS. In this study, we aimed to investigate the CC integrity and patterns of CC abnormalities in CIS with diffusion tensor group tractography.

MATERIALS AND METHODS

First, probability maps of the entire CC and its subregions (genu, body, and splenium) were created from 19 healthy subjects. Then these probability maps were used to evaluate diffusion within the entire CC and its segments in 19 patients with CIS. Five indices, including the midsagittal CC area, FA, MD, λ(1), and λ(23), were used to characterize CC integrity.

RESULTS

Significant differences were found between patients with CIS and healthy controls in the entire CC and its segments. For the entire CC, patients with CIS had a significantly lower midsagittal CC area and FA, higher MD and λ(23), with a trend toward higher λ(1). These 4 diffusion measures were correlated with T2 lesion volume. Moreover, abnormal white matter integrity was present in subregions of the CC; there was a robust significant increase in λ(23) in the body and splenium and no difference in λ(1) in the genu.

CONCLUSIONS

Our results suggest that atrophy and abnormal diffusion inside the CC appear at the stage of CIS and the severity of damage in the genu is milder than that in the body and splenium.

[Corpus callosum. Landmark of the origin of cerebral diseases]

Diseases of the corpus callosum include developmental disorders, immunomodulated CNS diseases, vascular malformations, disturbances of metabolism including the electrolyte homeostasis, secondary degenerations and mechanical injuries. This report provides information on the differential diagnosis of reversible and irreversible pathological changes of the corpus callosum with special focus on the localization, which often allows conclusions on the pathogenesis to be drawn.