Spinal cord atrophy in multiple sclerosis and relationship with disability across clinical phenotypes

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Relationship between cervical spinal cord morphometry and clinical disability in patients with multiple sclerosis

OBJECTIVE

Multiple sclerosis is an autoimmune disease that commonly affects the cervical part of the spinal cord. The aim of this study was to evaluate the relationship between cervical spinal cord atrophy and clinical disability in multiple sclerosis patients.

METHODS

We examined the cervical spinal cord area measurements of 64 multiple sclerosis patients and 64 healthy control groups over the images obtained by a T2-weighted magnetic resonance imaging device.

RESULTS

The C2-3, C3-4, C4-5, and C6-7 axial cross-sectional surface area values of the patient group were statistically lower than those of the control group (p<0.05). A negative correlation was found between patients' Expanded Disability Status Scale scores and C4-5, C5-6, and C6-7 axial area (axial area p<0.05; r1=-0.472, r2=-0.513, and r3=-0.415).

CONCLUSION

When all parameters were evaluated, the data of our control group were found to be higher than the multiple sclerosis groups. There appears to be a significant relationship between patients with cervical spinal cord atrophy and an increase in Expanded Disability Status Scale scores.

Radiological features of late-onset multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Late-onset multiple sclerosis (LOMS) is most commonly defined as the onset of the disease's presentations at age 50 or older. There is still much to discover about the radiological features of LOMS. The current study aims to assess the imaging features of LOMS, as well as the correlation between these findings and the clinical characteristics of these patients.

METHOD

This study was conducted following the PRISMA statement. A systematic search was conducted through PubMed, Scopus, and EMBASE databases to identify the studies that have applied magnetic-resonance imaging (MRI) or other imaging methods to investigate the radiological findings, as well as the relationship between them and clinical findings of LOMS patients. The risk of bias was assessed using the Joanna Briggs Institute (JBI) checklists. Meta-analysis was conducted using the third version of the compressive meta-analysis software (CMA3).

RESULTS

Our search identified 753 unique titles. Among them, 15 studies, including seven case-control, five case-series, and three cross-sectional studies, met the eligibility criteria. According to the quantitative synthesis, brain lesions were detected among 72.2% of LOMS patients (4 studies; 95% CI: 67.0% - 93.1%). In the context of spinal lesions, overall spinal cord involvement was 64.0% (8 studies; 95% CI: 42.5% - 81.1%). Based on the available evidence, supratentorial involvement was found in 82.7% of cases (3 studies; 95% CI: 17.4% - 99.1%), juxtacortical involvement in 34.1% (3 studies; 95% CI: 26.4% - 42.7%), infratentorial involvement in 51.3% (4 studies; 95% CI: 32.1% - 70.1%), and cerebellar involvement in 18.5% (3 studies; 95% CI: 13.9% - 24.1%).

CONCLUSION

Based on the neuroimaging findings, we found that, given the heterogeneity of MS, LOMS patients have a high rate of spinal cord lesions and supratentorial involvement. The limited available evidence suggests that Barkhof criteria are the best compromise for the diagnosis of LOMS. There is still a need for future studies.

Predictors of long-term disability in multiple sclerosis patients using routine magnetic resonance imaging data: A 15-year retrospective study

INTRODUCTION

Early identification of patients at high risk of progression could help with a personalised treatment strategy. Magnetic resonance imaging (MRI) measures have been proposed to predict long-term disability in multiple sclerosis (MS), but a reliable predictor that can be easily implemented clinically is still needed.

AIM

Assess MRI measures during the first 5 years of the MS disease course for the ability to predict progression at 10+ years.

METHODS

Eighty-two MS patients (53 females), with ≥10 years of clinical follow-up and having two MRI scans, were included. Clinical data were obtained at baseline, follow-up and at ≥10 years. White matter lesion (WML) counts and volumes, and four linear brain sizes were measured on T2/FLAIR 'Fluid-Attenuated-Inversion-Recovery' and T1-weighted images.

RESULTS

Baseline and follow-up inter-caudate diameter (ICD) and third ventricular width (TVW) measures correlated positively with Expanded Disability Status Scale, ≥10 or more of WMLs showed a high sensitivity in predicting progression, at ≥10 years. A steeper rate of lesion volume increase was observed in subjects converting to secondary progressive MS. The sensitivity and specificity of both ICD and TVW, to predict disability at ≥10 years were 60% and 64%, respectively.

CONCLUSION

Despite advances in brain imaging and computerised volumetric analysis, ICD and TVW remain relevant as they are simple, fast and have the potential in predicting long-term disability. However, in this study, despite the statistical significance of these measures, the clinical utility is still not reliable.

Incremental validity of brief and abbreviated neuropsychological tests toward predicting functional outcomes in multiple sclerosis

OBJECTIVE

This study examined the relationships among functional outcomes and performance on standard-length and abbreviated cognitive screening measures for multiple sclerosis (MS).

METHOD

72 adults with MS underwent neurological examination and cognitive screening. They completed standard-length and abbreviated versions of tests from the Minimal Assessment of Cognitive Function in MS (MACFIMS), the abbreviated aMACFIMS, and the Brief International Cognitive Assessment for MS (BICAMS). Functional outcomes included neurological disability, physical and psychological dysfunction, and employment status.

RESULTS

Concordance of impairment classifications was examined between standard-length and abbreviated tests using logistic regression and ROC curve analyses. Overall, the abbreviated test versions showed a broad range of concordance with impairment classifications made using the full-length tests. Processing speed was the strongest correlate of neurological disability and employment status; immediate recall was the strongest predictor of subjective physical dysfunction. Test performance provided unique value toward predicting neurological disability and employment status, but not physical and psychological dysfunction.

CONCLUSIONS

The findings replicate some support for abbreviated tests in MS assessment, although caveats regarding loss of validity associated with abbreviation remain. The findings extend prior research showing that abbreviated tests of processing speed and immediate recall can provide unique predictive information regarding objective functional outcomes.

Communicating the relevance of neurodegeneration and brain atrophy to multiple sclerosis patients: patient, provider and researcher perspectives

Central nervous system (CNS) atrophy provides valuable additional evidence of an ongoing neurodegeneration independent of lesion accrual in persons with multiple sclerosis (PwMS). However, there are limitations for interpretation of CNS volume changes at individual patient-level. Patients are receiving information on the topic of atrophy through various sources, including media, patient support groups and conferences, and discussions with their providers. Whether or not the topic of CNS atrophy should be proactively discussed with PwMS during office appointments is currently controversial. This commentary/perspective article represents perspectives of PwMS, providers and researchers with recommendations for minimizing confusion and anxiety, and facilitating proactive discussion about brain atrophy, as an upcoming routine measure in evaluating disease progression and treatment response monitoring. The following recommendations were created based on application of patient's and provider's surveys, and various workshops held over a period of 2 years: (1) PwMS should receive basic information on understanding of brain functional anatomy, and explanation of inflammation and neurodegeneration; (2) the expertise for atrophy measurements should be characterized as evolving; (3) quality patient education materials on these topics should be provided; (4) the need for standardization of MRI exams has to be explained and communicated; (5) providers should discuss background on volumetric changes, including references to normal aging; (6) the limitations of brain volume assessments at an individual-level should be explained; (7) the timing and language used to convey this information should be individualized based on the patient's background and disease status; (8) a discussion guide may be a very helpful resource for use by providers/staff to support these discussions; (9) understanding the role of brain atrophy and other MRI metrics may elicit greater patient satisfaction and acceptance of the value of therapies that have proven efficacy around these outcomes; (10) the areas that represent possibilities for positive self-management of MS symptoms that foster hope for improvement should be emphasized, and in particular regarding use of physical and mental exercise that build or maintain brain reserve through increased network efficiency, and (11) an additional time during clinical visits should be allotted to discuss these topics, including creation of specific educational programs.

Neurodegeneration in multiple sclerosis

Axonal loss in multiple sclerosis (MS) is a key component of disease progression and permanent neurologic disability. MS is a heterogeneous demyelinating and neurodegenerative disease of the central nervous system (CNS) with varying presentation, disease courses, and prognosis. Immunomodulatory therapies reduce the frequency and severity of inflammatory demyelinating events that are a hallmark of MS, but there is minimal therapy to treat progressive disease and there is no cure. Data from patients with MS, post-mortem histological analysis, and animal models of demyelinating disease have elucidated patterns of MS pathogenesis and underlying mechanisms of neurodegeneration. MRI and molecular biomarkers have been proposed to identify predictors of neurodegeneration and risk factors for disease progression. Early signs of axonal dysfunction have come to light including impaired mitochondrial trafficking, structural axonal changes, and synaptic alterations. With sustained inflammation as well as impaired remyelination, axons succumb to degeneration contributing to CNS atrophy and worsening of disease. These studies highlight the role of chronic demyelination in the CNS in perpetuating axonal loss, and the difficulty in promoting remyelination and repair amidst persistent inflammatory insult. Regenerative and neuroprotective strategies are essential to overcome this barrier, with early intervention being critical to rescue axonal integrity and function. The clinical and basic research studies discussed in this review have set the stage for identifying key propagators of neurodegeneration in MS, leading the way for neuroprotective therapeutic development. This article is categorized under: Immune System Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology.

Molecular models of multiple sclerosis severity identify heterogeneity of pathogenic mechanisms

While autopsy studies identify many abnormalities in the central nervous system (CNS) of subjects dying with neurological diseases, without their quantification in living subjects across the lifespan, pathogenic processes cannot be differentiated from epiphenomena. Using machine learning (ML), we searched for likely pathogenic mechanisms of multiple sclerosis (MS). We aggregated cerebrospinal fluid (CSF) biomarkers from 1305 proteins, measured blindly in the training dataset of untreated MS patients (N = 129), into models that predict past and future speed of disability accumulation across all MS phenotypes. Healthy volunteers (N = 24) data differentiated natural aging and sex effects from MS-related mechanisms. Resulting models, validated (Rho 0.40-0.51, p < 0.0001) in an independent longitudinal cohort (N = 98), uncovered intra-individual molecular heterogeneity. While candidate pathogenic processes must be validated in successful clinical trials, measuring them in living people will enable screening drugs for desired pharmacodynamic effects. This will facilitate drug development making, it hopefully more efficient and successful.

Myelitis features and outcomes in CNS demyelinating disorders: Comparison between multiple sclerosis, MOGAD, and AQP4-IgG-positive NMOSD

Inflammatory myelopathies can manifest with a combination of motor, sensory and autonomic dysfunction of variable severity. Depending on the underlying etiology, the episodes of myelitis can recur, often leading to irreversible spinal cord damage and major long-term disability. Three main demyelinating disorders of the central nervous system, namely multiple sclerosis (MS), aquaporin-4-IgG-positive neuromyelitis optica spectrum disorders (AQP4+NMOSD) and myelin oligodendrocyte glycoprotein-IgG associated disease (MOGAD), can induce spinal cord inflammation through different pathogenic mechanisms, resulting in a more or less profound disruption of spinal cord integrity. This ultimately translates into distinctive clinical-MRI features, as well as distinct patterns of disability accrual, with a step-wise worsening of neurological function in MOGAD and AQP4+NMOSD, and progressive disability accrual in MS. Early recognition of the specific etiologies of demyelinating myelitis and initiation of the appropriate treatment is crucial to improve outcome. In this review article we summarize and compare the clinical and imaging features of spinal cord involvement in these three demyelinating disorders, both during the acute phase and over time, and outline the current knowledge on the expected patterns of disability accrual and outcomes. We also discuss the potential implications of these observations for patient management and counseling.

Relaxometry and brain myelin quantification with synthetic MRI in MS subtypes and their associations with spinal cord atrophy

Immune-mediated demyelination and neurodegeneration are pathophysiological hallmarks of Multiple Sclerosis (MS) and main drivers of disease related disability. The principal method for evaluating qualitatively demyelinating events in the clinical context is contrast-weighted magnetic resonance imaging (MRI). Moreover, advanced MRI sequences provide reliable quantification of brain myelin offering new opportunities to study tissue pathology in vivo. Towards neurodegenerative aspects of the disease, spinal cord atrophy - besides brain atrophy - is a powerful and validated predictor of disease progression. The etiology of spinal cord volume loss is still a matter of research, as it remains unclear whether the impact of local lesion pathology or the interaction with supra- and infratentorial axonal degeneration and demyelination of the long descending and ascending fiber tracts are the determining factors. Quantitative synthetic MR using a multiecho acquisition of saturation recovery pulse sequence provides fast automatic brain tissue and myelin volumetry based on R1 and R2 relaxation rates and proton density quantification, making it a promising modality for application in the clinical routine. In this cross sectional study a total of 91 MS patients and 31 control subjects were included to investigate group differences of global and regional measures of brain myelin and relaxation rates, in different MS subtypes, using QRAPMASTER sequence and SyMRI postprocessing software. Furthermore, we examined associations between these quantitative brain parameters and spinal cord atrophy to draw conclusions about possible pathophysiological relationships. Intracranial myelin volume fraction of the global brain exhibited statistically significant differences between control subjects (10.4%) and MS patients (RRMS 9.4%, PMS 8.1%). In a LASSO regression analysis with total brain lesion load, intracranial myelin volume fraction and brain parenchymal fraction, the intracranial myelin volume fraction was the variable with the highest impact on spinal cord atrophy (standardized coefficient 4.52). Regional supratentorial MRI metrics showed altered average myelin volume fraction, R1, R2 and proton density in MS patients compared to controls most pronounced in PMS. Interestingly, quantitative MRI parameters in supratentorial regions showed strong associations with upper cord atrophy, suggesting an important role of brain diffuse demyelination on spinal cord pathology possibly in the context of global disease activity. R1, R2 or proton density of the thalamus, cerebellum and brainstem correlated with upper cervical cord atrophy, probably reflecting the direct functional connection between these brain structures and the spinal cord as well as the effects of retrograde and anterograde axonal degeneration. By using Synthetic MR-derived myelin volume fraction, we were able to effectively detect significant differences of myelination in relapsing and progressive MS subtypes. Total intracranial brain myelin volume fraction seemed to predict spinal cord volume loss better than brain atrophy or total lesion load. Furthermore, demyelination in highly myelinated supratentorial regions, as an indicator of diffuse disease activity, as well as alterations of relaxation parameters in adjacent infratentorial and midbrain areas were strongly associated with upper cervical cord atrophy.

The course of cervical spinal cord atrophy rate and its relationship with NEDA in relapsing remitting multiple sclerosis

This study aimed to compare the annualized segmental cervical spinal cord atrophy rate (ASCAR) in the early and late stages of relapsing remitting multiple sclerosis (RRMS), and to investigate the relationship between ASCAR and no evidence of disease activity (NEDA) in RRMS. Participants in this study included early stage MS (EMSg) patients, late stage MS (LMSg) patients, and healthy controls. All of the included participants (n = 175 subjects) were followed up for 14 months, and an MRI was performed on each participant at the beginning and at the end of the study. Cervical spinal cord average segmental area (CSCA) was measured by a semi-automated method, and ASCAR (mm²/year) was calculated. Data from the EMSg (n = 81 subjects) and LMSg (n = 94 subjects) patient groups were compared with each other and with the control group (n = 43 subjects). Examination of the initial CSCA values revealed that the baseline CSCA of the control group was larger than that of the EMSg (p < 0.001), and the baseline CSCA of the EMSg was larger than that of the LMSg (p < 0.001). The ASCAR of the control group, LMSg, and EMSg were 0.48, 0.93, and 1.81 mm² (p < 0.001), respectively. Regression analysis revealed that disability increase was associated with ASCAR, while MRI activity and relapse presence were unrelated to ASCAR. In both patient groups, ASCAR was slower in those who fulfilled NEDA but this relationship was not significant. Cervical spinal cord atrophy progression over time occurs at a greater rate in the early stages of RRMS disease compared to the late stages. ASCAR was unrelated to MRI activity and relapse, which are clinical markers of acute inflammation.

Multiple sclerosis impairment scale and brain MRI in secondary progressive multiple sclerosis

OBJECTIVE

To examine the Multiple Sclerosis Impairment Scale (MSIS) in secondary progressive MS (SPMS) in relation to the Expanded Disability Status Scale (EDSS), magnetic resonance imaging (MRI) outcomes, and mobility.

METHODS

In this observational single-center study, 68 secondary progressive multiple sclerosis (SPMS) patients were examined by MSIS, EDSS, functional mobility tests of upper/lower extremities, and multimodal MRI. Participants had EDSS ≥3.5, a decline in daily activities over the last year unrelated to relapses, and/or 6-month confirmed disability progression.

RESULTS

Mean disease duration was 23.1 ± 8.3 years and mean age 54.4 ± 8.1 years. MSIS, EDSS, and their corresponding motor, cerebellar, and sensory subscores correlated (p < .0001). Motor subscores of MSIS correlated stronger with Timed-25-Foot-Walk (T25FW) than pyramidal functional system score (FSS) (p = .03), but EDSS had a stronger correlation to T25FW than the total MSIS score (p = .01). MSIS cerebellar subscore correlated stronger with 9-Hole Peg Test (9-HPT) than cerebellar FSS (p = .04). The sensory MSIS subscore also showed correlation with 9-HPT in contrast to sensory FSS (p = .006). MSIS subscores had stronger correlations with MRI volumetry measures than FSS scores (lesion volume and putamen, thalamus, corpus callosum volumetry, p = .0001-0.0017).

CONCLUSION

In patients with SPMS, MSIS correlated with functional motor tests. MSIS showed stronger correlations with atrophy of central nervous system areas, and may be more sensitive to scale cerebellar and sensory function than EDSS.

Design and Validation of an Expanded Disability Status Scale Model in Multiple Sclerosis

INTRODUCTION

We aimed to develop and validate an Expanded Disability Status Scale (EDSS) model through clinical, optical coherence tomography (OCT), and magnetic resonance imaging (MRI) measures.

METHODS

Sixty-four multiple sclerosis (MS) patients underwent peripapillary retinal nerve fiber layer and segmented macular layers evaluation through OCT (Spectralis, Heidelberg Engineering). Brain parenchymal fraction was quantified through Freesurfer, while cervical spinal cord (SC) volume was assessed manually guided by Spinal Cord Toolbox software analysis. EDSS, neuroradiological, and OCT assessment were carried out within 3 months. OCT parameters were calculated as the average of both nonoptic neuritis (ON) eyes, and in case the patient had previous ON, the value of the fellow non-ON eye was taken. Brain lesion volume, sex, age, disease duration, and history of disease-modifying treatment (1st or 2nd line disease-modifying treatments) were tested as covariables of the EDSS score.

RESULTS

EDSS values correlated with patient's age (r = 0.543, p = 0.001), SC volume (r = -0.301, p = 0.034), and ganglion cell layer (GCL, r = -0.354, p = 0.012). Using these correlations, an ordinal regression model to express probability of diverse EDSS scores were designed, the highest of which was the most probable (Nagelkerke R2 = 43.3%). Using EDSS cutoff point of 4.0 in a dichotomous model, compared to a cutoff of 2.0, permits the inclusion of GCL as a disability predictor, in addition to age and SC.

CONCLUSIONS

MS disability measured through EDSS is an age-dependent magnitude that is partly conditioned by SC and GCL. Further studies assessing paraclinical disability predictors are needed.

Cervical and thoracic cord atrophy in multiple sclerosis phenotypes: Quantification and correlation with clinical disability

•

Spinal cord atrophy is prevalent across multiple sclerosis phenotypes.

•

It correlates with disability, especially in relapsing-remitting patients.

•

This correlation can be demonstrated both cross-sectionally and longitudinally.

•

Cervical atrophy is highly associated with disability and disease progression.

•

Thoracic atrophy contributes to improved correlation and radiological subgrouping.

Objective

We sought to characterize spinal cord atrophy along the entire spinal cord in the major multiple sclerosis (MS) phenotypes, and evaluate its correlation with clinical disability.

Methods

Axial T₁-weighted images were automatically reformatted at each point along the cord. Spinal cord cross‐sectional area (SCCSA) were calculated from C1-T10 vertebral body levels and profile plots were compared across phenotypes. Average values from C2-3, C4-5, and T4-9 regions were compared across phenotypes and correlated with clinical scores, and then categorized as atrophic/normal based on z-scores derived from controls, to compare clinical scores between subgroups. In a subset of relapsing-remitting cases with longitudinal scans these regions were compared to change in clinical scores.

Results

The cross-sectional study consisted of 149 adults diagnosed with relapsing-remitting MS (RRMS), 49 with secondary-progressive MS (SPMS), 58 with primary-progressive MS (PPMS) and 48 controls. The longitudinal study included 78 RRMS cases. Compared to controls, all MS groups had smaller average regions except RRMS in T4-9 region. In all MS groups, SCCSA from all regions, particularly the cervical cord, correlated with most clinical measures. In the RRMS cohort, 22% of cases had at least one atrophic region, whereas in progressive MS the rate was almost 70%. Longitudinal analysis showed correlation between clinical disability and cervical cord thinning.

Conclusions

Spinal cord atrophy was prevalent across MS phenotypes, with regional measures from the RRMS cohort and the progressive cohort, including SPMS and PPMS, being correlated with disability. Longitudinal changes in the spinal cord were documented in RRMS cases, making it a potential marker for disease progression. While cervical SCCSA correlated with most disability and progression measures, inclusion of thoracic measurements improved this correlation and allowed for better subgrouping of spinal cord phenotypes. Cord atrophy is an important and easily obtainable imaging marker of clinical and sub-clinical progression in all MS phenotypes, and such measures can play a key role in patient selection for clinical trials.

Imaging of the Spinal Cord in Multiple Sclerosis: Past, Present, Future

Spinal cord imaging in multiple sclerosis (MS) plays a significant role in diagnosing and tracking disease progression. The spinal cord is one of four key areas of the central nervous system where documenting the dissemination in space in the McDonald criteria for diagnosing MS. Spinal cord lesion load and the severity of cord atrophy are believed to be more relevant to disability than white matter lesions in the brain in different phenotypes of MS. Axonal loss contributes to spinal cord atrophy in MS and its degree correlates with disease severity and prognosis. Therefore, measures of axonal loss are often reliable biomarkers for monitoring disease progression. With recent technical advances, more and more qualitative and quantitative MRI techniques have been investigated in an attempt to provide objective and reliable diagnostic and monitoring biomarkers in MS. In this article, we discuss the role of spinal cord imaging in the diagnosis and prognosis of MS and, additionally, we review various techniques that may improve our understanding of the disease.

Prognostic value of spinal cord MRI in multiple sclerosis patients

Multiple sclerosis [MS] is a common inflammatory, demyelinating and neurodegenerative disease of the central nervous system that affects both the brain and the spinal cord. In clinical practice, spinal cord MRI is performed far less frequently than brain MRI, mainly owing to technical limitations and time constraints. However, improvements of acquisition techniques, combined with a strong diagnosis and prognostic value, suggest an increasing use of spinal cord MRI in the near future. This review summarizes the current data from the literature on the prognostic value of spinal cord MRI in MS patients in the early and later stages of their disease. Both conventional and quantitative MRI techniques are discussed. The prognostic value of spinal cord lesions is clearly established at the onset of disease, underlining the interest of spinal cord conventional MRI at this stage. However, studies are currently lacking to affirm the prognostic role of spinal cord lesions later in the disease, and therefore the added value of regular follow-up with spinal cord MRI in addition to brain MRI. Besides, spinal cord atrophy, as measured by the loss of cervical spinal cord area, is also associated with disability progression, independently of other clinical and MRI factors including spinal cord lesions. Although potentially interesting, this measurement is not currently performed as a routine clinical procedure. Finally, other measures extracted from quantitative MRI have been established as valuable for a better understanding of the physiopathology of MS, but still remain a field of research.

Approved and Emerging Disease Modifying Therapies on Neurodegeneration in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune, chronic, progressive disease leading to a combination of inflammation, demyelination, and neurodegeneration throughout the central nervous system (CNS). The outcome of these processes can be visualized in magnetic resonance imaging (MRI) scans as brain atrophy, or brain volume loss (BVL), as well as lesions, “black holes” and spinal cord atrophy. MRI outcomes such as BVL have been used as biomarkers of neurodegeneration and other measures of MS disease progression in clinical research settings. Several FDA-approved medications seek to alleviate disease progression by reducing the impact of such factors as demyelination and neurodegeneration, but there are still many shortcomings that current clinical research aims to mitigate. This review attempts to provide an overview of the FDA-approved medications available for treating multiple sclerosis and their effect on neurodegeneration, measured by BVL.

MRI biomarkers of disease progression and conversion to secondary-progressive multiple sclerosis

INTRODUCTION

Conventional imaging measures remain a key clinical tool for the diagnosis multiple sclerosis (MS) and monitoring of patients. However, most measures used in the clinic show unsatisfactory performance in predicting disease progression and conversion to secondary progressive MS.

AREAS COVERED

Sophisticated imaging techniques have facilitated the identification of imaging biomarkers associated with disease progression, such as global and regional brain volume measures, and with conversion to secondary progressive MS, such as leptomeningeal contrast enhancement and chronic inflammation. The relevance of emerging imaging approaches partially overcoming intrinsic limitations of traditional techniques is also discussed.

EXPERT OPINION

Imaging biomarkers capable of detecting tissue damage early on in the disease, with the potential to be applied in multicenter trials and at an individual level in clinical settings, are strongly needed. Several measures have been proposed, which exploit advanced imaging acquisitions and/or incorporate sophisticated post-processing, can quantify irreversible tissue damage. The progressively wider use of high-strength field MRI and the development of more advanced imaging techniques will help capture the missing pieces of the MS puzzle. The ability to more reliably identify those at risk for disability progression will allow for earlier intervention with the aim to favorably alter the disease course.

Correlation between EDSS scores and cervical spinal cord atrophy at 3T MRI in multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Cervical spinal cord atrophy (CSCA), which partly reflects the axonal loss in the spinal cord, is increasingly recognized as a valuable predictor of disease outcome. However, inconsistent results have been reported regarding the correlation of CSCA and clinical disability in multiple sclerosis (MS). The aim of this meta-analysis was to synthesize the available data obtained from 3.0-Tesla (3T) MRI scanners and to explore the relationship between CSCA and scores on the Expanded Disability Status Scale (EDSS).

METHODS

We searched PubMed, Embase, and Web of Science for articles published from the database inception to February 1, 2019. The quality of the articles was assessed according to a quality evaluation checklist which was created based on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. We conducted a meta-analysis of the correlation between EDSS scores and CSCA at 3T MRI in MS.

RESULTS

Twenty-two eligible studies involving 1933 participants were incorporated into our meta-analysis. Our results demonstrated that CSCA was negatively and moderately correlated with EDSS scores (r_s = -0.42, 95% CI: -0.51 to -0.32; p < 0.0001). Subgroup analyses revealed a weaker correlation in the group of relapsing-remitting multiple sclerosis (RRMS) and clinically isolated syndrome (CIS) (r_s = -0.19, 95% CI: -0.31 to -0.07; p = 0.0029).

CONCLUSIONS

The correlation between CSCA and EDSS scores was significant but moderate. We encourage more studies using reliable and consistent methods to explore whether CSCA is suitable as a predictor for MS progression.

The impact of cervical spinal cord atrophy on quality of life in multiple sclerosis

BACKGROUND

Spinal cord demyelination is common in multiple sclerosis (MS) and has been linked to increased disability and progressive clinical course. Spinal cord atrophy shows an especially close relationship to MS-related physical disability, though the relationship between spinal cord lesions/atrophy and health-related quality of life (QOL) has not been explored.

METHODS

62 patients (53 relapsing MS, 7 secondary progressive, 2 clinically isolated syndrome) from our center underwent 3 T MRI within 30 days of clinical examination and QOL assessment. Upper cervical (C1-C3) spinal cord area (UCCA) was obtained from 3D high-resolution MPRAGE sequences (1 mm isotropic voxels). Cervical spinal cord (C1-C7) lesion count, and cervical and brain T2 hyperintense lesion volumes were calculated. Brain parenchymal fraction (BPF) was obtained from an automated segmentation pipeline. Spearman correlations were assessed between MRI and clinical data. Partial Spearman correlations adjusting for age, disease duration, and BPF assessed the independent association between MRI variables and QOL domains.

RESULTS

UCCA showed an inverse relationship with age (r = -0.330, p = .009), disease duration, (r = -0.444, p < .001), and nine-hole peg test (r = -0.353, p = .005). The Upper Extremity Function QOL domain showed the strongest relationship to UCCA (r = 0.333, p = .008), with Lower Extremity Function QOL (r = 0.234, p = .067) and Satisfaction with Social Roles and Activities (r = 0.245, p = .055) correlations bordering significance. The association between UCCA and Upper Extremity QOL remained significant after adjustment for BPF, age, and disease duration. QOL domains reflective of psychological health (Depression, Anxiety, Emotional and Behavioral Dyscontrol, Positive Affect and Wellbeing) showed no relationship to UCCA. Cervical and brain lesion volume related to impairment in Stigma while cervical lesion count was unrelated to NeuroQOL impairment. Brain atrophy correlated with conventional markers of disability and cognition but did not have a significant relationship to QOL.

CONCLUSION

Cervical spinal cord volume is independently associated with impaired upper extremity-related QOL in patients with MS. These findings suggest specific clinical relevance of MS-related spinal cord atrophy as compared to brain or cervical spinal cord lesions, or whole brain atrophy.

MRI in multiple sclerosis: clinical and research update

PURPOSE OF REVIEW

Clinical MRI is of paramount importance for multiple sclerosis diagnosis but lacks the specificity to investigate the pathogenic mechanisms underlying disease onset and progression. The application of advanced MR sequences allows the characterization of diverse and complex pathological mechanisms, granting insights into multiple sclerosis natural history and response to treatment.

RECENT FINDINGS

This review provides an update on the most recent international guidelines for optimal standard imaging of multiple sclerosis and discusses advantages and limitations of advanced imaging approaches for investigating inflammation, demyelination and neurodegeneration. An overview is provided for methods devoted to imaging leptomeningeal enhancement, microglial activation, demyelination, neuronal metabolic damage and neuronal loss.

SUMMARY

The application of magnetic resonance (MR) guidelines to standard-of-care MR protocols, although still limited, would substantially contribute to the optimization of multiple sclerosis management. From an academic perspective, different mechanism-specific imaging techniques are available and offer a powerful tool to elucidate multiple sclerosis pathogenesis, monitor disease progression and guide therapeutic choices.

Spinal Cord Atrophy in Multiple Sclerosis: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Spinal cord atrophy (SCA) is an important emerging outcome measure in multiple sclerosis (MS); however, there is limited consensus on the magnitude and rate of atrophy. The objective of this study was to synthesize the available data on measures of SCA in MS.

METHODS

Using published guidelines, relevant literature databases were searched between 1977 and 2017 for case-control or cohort studies reporting a quantitative measure of SCA in MS patients. Random-effects models pooled cross-sectional measures and longitudinal rates of SCA in MS and healthy controls (HCs). Student's t-test assessed differences between pooled measures in patient subgroups. Heterogeneity was assessed using DerSimonian and Laird's Q-test and the I ² -index.

RESULTS

A total of 1,465 studies were retrieved including 94 that met inclusion and exclusion criteria. Pooled estimates of mean cervical spinal cord (SC) cross-sectional area (CSA) in all MS patients, relapsing-remitting MS (RRMS), all progressive MS, secondary progressive MS (SPMS), primary-progressive MS (PPMS), and HC were: 73.07 mm² (95% CI [71.52-74.62]), 78.88 mm² (95% CI [76.92-80.85]), 69.72 mm² (95% CI [67.96-71.48]), 68.55 mm² (95% CI [65.43-71.66]), 70.98 mm² (95% CI [68.78-73.19]), and 80.87 mm² (95% C I [78.70-83.04]), respectively. Pooled SC-CSA was greater in HC versus MS (P < .001) and RRMS versus progressive MS (P < .001). SCA showed moderate correlations with global disability in cross-sectional studies (r-value with disability score range [-.75 to -.22]). In longitudinal studies, the pooled annual rate of SCA was 1.78%/year (95%CI [1.28-2.27]).

CONCLUSIONS

The SC is atrophied in MS. The magnitude of SCA is greater in progressive versus relapsing forms and correlates with clinical disability. The pooled estimate of annual rate of SCA is greater than reported rates of brain atrophy in MS. These results demonstrate that SCA is highly relevant as an imaging outcome in MS clinical trials.

Spinal cord volume loss: A marker of disease progression in multiple sclerosis

OBJECTIVE

Cross-sectional studies have shown that spinal cord volume (SCV) loss is related to disease severity in multiple sclerosis (MS). However, long-term data are lacking. Our aim was to evaluate SCV loss as a biomarker of disease progression in comparison to other MRI measurements in a large cohort of patients with relapse-onset MS with 6-year follow-up.

METHODS

The upper cervical SCV, the total brain volume, and the brain T2 lesion volume were measured annually in 231 patients with MS (180 relapsing-remitting [RRMS] and 51 secondary progressive [SPMS]) over 6 years on 3-dimensional, T1-weighted, magnetization-prepared rapid-acquisition gradient echo images. Expanded Disability Status Scale (EDSS) score and relapses were recorded at every follow-up.

RESULTS

Patients with SPMS had lower baseline SCV (p < 0.01) but no accelerated SCV loss compared to those with RRMS. Clinical relapses were found to predict SCV loss over time (p < 0.05) in RRMS. Furthermore, SCV loss, but not total brain volume and T2 lesion volume, was a strong predictor of EDSS score worsening over time (p < 0.05). The mean annual rate of SCV loss was the strongest MRI predictor for the mean annual EDSS score change of both RRMS and SPMS separately, while correlating stronger in SPMS. Every 1% increase of the annual SCV loss rate was associated with an extra 28% risk increase of disease progression in the following year in both groups.

CONCLUSION

SCV loss over time relates to the number of clinical relapses in RRMS, but overall does not differ between RRMS and SPMS. SCV proved to be a strong predictor of physical disability and disease progression, indicating that SCV may be a suitable marker for monitoring disease activity and severity.

Axonal loss in the multiple sclerosis spinal cord revisited

Preventing chronic disease deterioration is an unmet need in people with multiple sclerosis, where axonal loss is considered a key substrate of disability. Clinically, chronic multiple sclerosis often presents as progressive myelopathy. Spinal cord cross-sectional area (CSA) assessed using MRI predicts increasing disability and has, by inference, been proposed as an indirect index of axonal degeneration. However, the association between CSA and axonal loss, and their correlation with demyelination, have never been systematically investigated using human post mortem tissue. We extensively sampled spinal cords of seven women and six men with multiple sclerosis (mean disease duration= 29 years) and five healthy controls to quantify axonal density and its association with demyelination and CSA. 396 tissue blocks were embedded in paraffin and immuno-stained for myelin basic protein and phosphorylated neurofilaments. Measurements included total CSA, areas of (i) lateral cortico-spinal tracts, (ii) gray matter, (iii) white matter, (iv) demyelination, and the number of axons within the lateral cortico-spinal tracts. Linear mixed models were used to analyze relationships. In multiple sclerosis CSA reduction at cervical, thoracic and lumbar levels ranged between 19 and 24% with white (19-24%) and gray (17-21%) matter atrophy contributing equally across levels. Axonal density in multiple sclerosis was lower by 57-62% across all levels and affected all fibers regardless of diameter. Demyelination affected 24-48% of the gray matter, most extensively at the thoracic level, and 11-13% of the white matter, with no significant differences across levels. Disease duration was associated with reduced axonal density, however not with any area index. Significant association was detected between focal demyelination and decreased axonal density. In conclusion, over nearly 30 years multiple sclerosis reduces axonal density by 60% throughout the spinal cord. Spinal cord cross sectional area, reduced by about 20%, appears to be a poor predictor of axonal density.

Cardiac repolarization evolves differently during the course of benign and disabling multiple sclerosis

BACKGROUND

Cardiac repolarization is modulated by the autonomic nervous system. Even though multiple sclerosis associates with prolonged cardiac repolarization the physiology responsible for the phenomenon remains unknown.

OBJECTIVE

To study in longitudinal setting whether the patients with confirmed benign and disabling outcome of relapsing-remitting multiple sclerosis (RRMS) differ in regard to changes of cardiac repolarization.

METHODS

Total of 43 patients, 26% with benign (EDSS ≤2 at least 10y after onset symptom) and 74% with disabling (EDSS >2 at least 10y after onset symptom) RRMS, having 12-lead electrocardiogram (ECG) recorded at the time of onset symptom (ECG1) and for follow-up (ECG2), were studied. Heart rate (HR) corrected QT intervals (QTc) reflecting cardiac repolarization were assessed.

RESULTS

The time interval between ECG1 and ECG2 showed no statistical difference between benign (7.8 ± 4.8y) and disabling (10.2 ± 5.6y; p = .211) RRMS. Patients with benign and disabling RRMS showed similar values of HR (66±9 bpm vs 73 ± 15 bpm; p=.146) and QTc (403 ± 13 ms vs 408 ± 19 ms; p = .450) at the time of ECG1. However, at the time of ECG2, HR was higher (79 ± 14 bpm vs 65 ± 10 bpm; p = .004) and QTc was longer (420 ± 24 ms vs 400 ± 15 ms; p = .012) in patients with disabling than benign RRMS. Correspondingly, HR increased (p = .063) and QTc prolonged (p = .014) during the disease course only in patients with disabling RRMS.

CONCLUSIONS

Deterioration of cardiac autonomic regulation during the disease course associates with disabling but not with benign RRMS. Our findings suggest that assessment of cardiac autonomic regulation should be included in the evaluation of RRMS disease course. In addition, patients with disabling RRMS might be prone to unfavorable cardiovascular outcome also due to deterioration of autonomic nervous system.

Imaging spinal cord atrophy in progressive myelopathies: HTLV-I-associated neurological disease (HAM/TSP) and multiple sclerosis (MS)

OBJECTIVE

Previous work measures spinal cord thinning in chronic progressive myelopathies, including human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and multiple sclerosis (MS). Quantitative measurements of spinal cord atrophy are important in fully characterizing these and other spinal cord diseases. We aimed to investigate patterns of spinal cord atrophy and correlations with clinical markers.

METHODS

Spinal cord cross-sectional area was measured in individuals (24 healthy controls [HCs], 17 asymptomatic carriers of HTLV-1 (AC), 47 HAM/TSP, 74 relapsing-remitting MS [RRMS], 17 secondary progressive MS [SPMS], and 40 primary progressive MS [PPMS]) from C1 to T10. Clinical disability scores, viral markers, and immunological parameters were obtained for patients and correlated with representative spinal cord cross-sectional area regions at the C2 to C3, C4 to C5, and T4 to T9 levels. In 2 HAM/TSP patients, spinal cord cross-sectional area was measured over 3 years.

RESULTS

All spinal cord regions are thinner in HAM/TSP (56 mm² [standard deviation, 10], 59 [10], 23 [5]) than in HC (76 [7], 83 [8], 38 [4]) and AC (71 [7], 78 [9], 36 [7]). SPMS (62 [9], 66 [9], 32 [6]) and PPMS (65 [11], 68 [10], 35 [7]) have thinner cervical cords than HC and RRMS (73 [9], 77 [10], 37 [6]). Clinical disability scores (Expanded Disability Status Scale [p = 0.009] and Instituto de Pesquisas de Cananeia [p = 0.03]) and CD8⁺ T-cell frequency (p = 0.04) correlate with T4 to T9 spinal cord cross-sectional area in HAM/TSP. Higher cerebrospinal fluid HTLV-1 proviral load (p = 0.01) was associated with thinner spinal cord cross-sectional area. Both HAM/TSP patients followed longitudinally showed thoracic thinning followed by cervical thinning.

INTERPRETATION

Group average spinal cord cross-sectional area in HAM/TSP and progressive MS show spinal cord atrophy. We further hypothesize in HAM/TSP that is possible that neuroglial loss from a thoracic inflammatory process results in anterograde and retrograde degeneration of axons, leading to the temporal progression of thoracic to cervical atrophy described here. Ann Neurol 2017;82:719-728.

The Role of Advanced Magnetic Resonance Imaging Techniques in Multiple Sclerosis Clinical Trials

Magnetic resonance imaging has been crucial in the development of anti-inflammatory disease-modifying treatments. The current landscape of multiple sclerosis clinical trials is currently expanding to include testing not only of anti-inflammatory agents, but also neuroprotective, remyelinating, neuromodulating, and restorative therapies. This is especially true of therapies targeting progressive forms of the disease where neurodegeneration is a prominent feature. Imaging techniques of the brain and spinal cord have rapidly evolved in the last decade to permit in vivo characterization of tissue microstructural changes, connectivity, metabolic changes, neuronal loss, glial activity, and demyelination. Advanced magnetic resonance imaging techniques hold significant promise for accelerating the development of different treatment modalities targeting a variety of pathways in MS.

The Role of T1-Weighted Derived Measures of Neurodegeneration for Assessing Disability Progression in Multiple Sclerosis

Introduction

Multiple sclerosis (MS) is characterised by the accumulation of permanent neurological disability secondary to irreversible tissue loss (neurodegeneration) in the brain and spinal cord. MRI measures derived from T1-weighted image analysis (i.e., black holes and atrophy) are correlated with pathological measures of irreversible tissue loss. Quantifying the degree of neurodegeneration in vivo using MRI may offer a surrogate marker with which to predict disability progression and the effect of treatment. This review evaluates the literature examining the association between MRI measures of neurodegeneration derived from T1-weighted images and disability in MS patients.

Methods

A systematic PubMed search was conducted in January 2017 to identify MRI studies in MS patients investigating the relationship between “black holes” and/or atrophy in the brain and spinal cord, and disability. Results were limited to human studies published in English in the previous 10 years.

Results

A large number of studies have evaluated the association between the previous MRI measures and disability. These vary considerably in terms of study design, duration of follow-up, size, and phenotype of the patient population. Most, although not all, have shown that there is a significant correlation between disability and black holes in the brain, as well as atrophy of the whole brain and grey matter. The results for brain white matter atrophy are less consistently positive, whereas studies evaluating spinal cord atrophy consistently showed a significant correlation with disability. Newer ways of measuring atrophy, thanks to the development of segmentation and voxel-wise methods, have allowed us to assess the involvement of strategic regions of the CNS (e.g., thalamus) and to map the regional distribution of damage. This has resulted in better correlations between MRI measures and disability and in the identification of the critical role played by some CNS structures for MS clinical manifestations.

Conclusion

The evaluation of MRI measures of atrophy as predictive markers of disability in MS is a highly active area of research. At present, measurement of atrophy remains within the realm of clinical studies, but its utility in clinical practice has been recognized and barriers to its implementation are starting to be addressed.

Quantitative measures of walking and strength provide insight into brain corticospinal tract pathology in multiple sclerosis

At least 85% of individuals with multiple sclerosis report walking dysfunction as their primary complaint. Walking and strength measures are common clinical measures to mark increasing disability or improvement with rehabilitation. Previous studies have shown an association between strength or walking ability and spinal cord MRI measures, and strength measures with brainstem corticospinal tract magnetization transfer ratio. However, the relationship between walking performance and brain corticospinal tract magnetization transfer imaging measures and the contribution of clinical measurements of walking and strength to the underlying integrity of the corticospinal tract has not been explored in multiple sclerosis. The objectives of this study were explore the relationship of quantitative measures of walking and strength to whole-brain corticospinal tract-specific MRI measures and to determine the contribution of quantitative measures of function in addition to basic clinical measures (age, gender, symptom duration and Expanded Disability Status Scale) to structural imaging measures of the corticospinal tract. We hypothesized that quantitative walking and strength measures would be related to brain corticospinal tract-specific measures, and would provide insight into the heterogeneity of brain pathology. Twenty-nine individuals with relapsing-remitting multiple sclerosis (mean(SD) age 48.7 (11.5) years; symptom duration 11.9(8.7); 17 females; median[range] Expanded Disability Status Scale 4.0 [1.0-6.5]) and 29 age and gender-matched healthy controls (age 50.8(11.6) years; 20 females) participated in clinical tests of strength and walking (Timed Up and Go, Timed 25 Foot Walk, Two Minute Walk Test ) as well as 3 T imaging including diffusion tensor imaging and magnetization transfer imaging. Individuals with multiple sclerosis were weaker (p = 0.0024) and walked slower (p = 0.0013) compared to controls. Quantitative measures of walking and strength were significantly related to corticospinal tract fractional anisotropy (r > 0.26; p < 0.04) and magnetization transfer ratio (r > 0.29; p < 0.03) measures. Although the Expanded Disability Status Scale was highly correlated with walking measures, it was not significantly related to either corticospinal tract fractional anisotropy or magnetization transfer ratio (p > 0.05). Walk velocity was a significant contributor to magnetization transfer ratio (p = 0.006) and fractional anisotropy (p = 0.011) in regression modeling that included both quantitative measures of function and basic clinical information. Quantitative measures of strength and walking are associated with brain corticospinal tract pathology. The addition of these quantitative measures to basic clinical information explains more of the variance in corticospinal tract fractional anisotropy and magnetization transfer ratio than the basic clinical information alone. Outcome measurement for multiple sclerosis clinical trials has been notoriously challenging; the use of quantitative measures of strength and walking along with tract-specific imaging methods may improve our ability to monitor disease change over time, with intervention, and provide needed guidelines for developing more effective targeted rehabilitation strategies.

Is Time to Reach EDSS 6.0 Faster in Patients with Late-Onset versus Young-Onset Multiple Sclerosis?

BACKGROUND & OBJECTIVES

Published natural history data on late-onset of multiple sclerosis are limited. We aimed to assess the risk of attaining EDSS 6.0 among patients with late-onset (> 40 years) MS (LOMS) and young-onset (18-40 years) MS (YOMS).

METHODS

This cross-sectional cohort study was conducted to identify LOMS and YOMS patients' with relapsing remitting course at MS diagnosis. Time (years) to reach sustained EDSS 6.0 was compared between LOMS and AOMS patients. Cox proportional hazards model was used to evaluate the demographic and clinical predictors of time to EDSS 6.0 in these cohorts.

RESULTS

LOMS and YOMS cohorts comprised 99 (10.7%) and 804 (89.3%) patients respectively. Spinal cord presentation at MS onset was more common among LOMS patients (46.5% vs. 32.3%). The proportions of LOMS and YOMS patients reaching EDSS 6.0 during the follow-up period were 19.2% and 15.7% respectively. In multivariable Cox proportional hazards model, older age at MS onset (adjusted hazard ratio (aHR) = 3.96; 95% CI: 2.14-7.32; p < 0.001), male gender (aHR = 1.85; 95% CI: 1.22-2.81; p = 0.004) and spinal cord presentation at onset (aHR = 1.47; 95% CI: 0.98-2.21; p = 0.062) were significantly associated with shorter time to EDSS 6.0.

CONCLUSIONS

LOMS patients attained EDSS 6.0 in a significantly shorter period that was influenced by male gender and spinal cord presentation at MS onset.