Brain Atrophy in Multiple Sclerosis

Brain atrophy assessment in multiple sclerosis: technical- and subject-related barriers for translation to real-world application in individual subjects

INTRODUCTION

Brain atrophy is a well-established MRI outcome for predicting clinical progression and monitoring treatment response in persons with multiple sclerosis (pwMS) at the group level. Despite the important progress made, the translation of brain atrophy assessment into clinical practice faces several challenges.

AREAS COVERED

In this review, the authors discuss technical- and subject-related barriers for implementing brain atrophy assessment as part of the clinical routine at the individual level. Substantial progress has been made to understand and mitigate technical barriers behind MRI acquisition. Numerous research and commercial segmentation techniques for volume estimation are available and technically validated, but their clinical value has not been fully established. A systematic assessment of subject-related barriers, which include genetic, environmental, biological, lifestyle, comorbidity, and aging confounders, is critical for the interpretation of brain atrophy measures at the individual subject level. Educating both medical providers and pwMS will help better clarify the benefits and limitations of assessing brain atrophy for disease monitoring and prognosis.

EXPERT OPINION

Integrating brain atrophy assessment into clinical practice for pwMS requires overcoming technical and subject-related challenges. Advances in MRI standardization, artificial intelligence, and clinician education will facilitate this process, improving disease management and potentially reducing long-term healthcare costs.

Efficacy and safety of peginterferon beta-1a compared to interferon beta-1a in relapsing remitting multiple sclerosis patients: A phase 3, randomized, non-inferiority clinical trial (PEGINTEGRITY)

BACKGROUND

Multiple sclerosis (MS) is a prevalent, disabling, inflammatory, neurodegenerative disease that typically manifests during a highly productive stage of life. Interferon beta-1a was among the first approved disease-modifying therapies for MS and remains among the first-line treatment options. Pegylation of the interferon beta-1a molecule prolongs its half-life while maintaining its efficacy and safety profile. In PEGINTEGRITY study, we aimed to compare peginterferon beta-1a with interferon beta-1a in terms of efficacy and safety in relapsing-remitting multiple sclerosis (RRMS) patients.

METHODS

This study was a randomized, active-controlled, parallel-group, multi-center Phase 3 trial conducted in Iran in participants with RRMS. Participants received 125 µg of subcutaneous peginterferon beta-1a every two weeks or 30 µg of intramuscular interferon beta-1a once a week for up to 96 weeks. The primary outcome was the non-inferiority of peginterferon beta-1a to interferon beta-1a in reducing annualized relapse rate (ARR). Other outcomes included the number of patients with 12-week confirmed disability progression, the number of new or newly-enlarging T2 hyperintense lesions, the number of gadolinium-enhancing lesions, the number of new T1 hypointense lesions, the volume of new or newly-enlarging T2 hyperintense lesions, changes in brain volume, immunogenicity, and safety assessments.

RESULTS

A total of 168 patients who met the eligibility criteria were enrolled and assigned to two arms of the study, each consisting of 84 participants. Totally, 41 participants (24 patients in the peginterferon beta-1a group and 17 patients in the interferon beta-1a group) were withdrawn from the study. The withdrawn patients were included in the per-protocol analysis for the period of time they were in the study. In 96 weeks, in the per-protocol population, the ARR was 0.05 in the peginterferon beta-1a group versus 0.11 in the interferon beta-1a group, which does not reflect a statistically significant difference (p=0.09; 95 % CI, 0.18-1.14). Considering the upper limit of the one-sided 95 % CI of the rate ratio of peginterferon beta-1a compared to interferon beta-1a, as well as the non-inferiority margin, it can be concluded that the primary outcome was met. The results were also comparable for other efficacy and safety outcomes.

CONCLUSION

The results demonstrate the non-inferiority of peginterferon beta-1a to interferon beta-1a with similar efficacy in 96-week ARR in RRMS patients. Both arms were also comparable in other efficacy outcomes and safety profiles with no statistically significant differences. These findings support considering peginterferon beta-1a as a safe and efficient option in patients with RRMS. This study was registered on Iranian Registry of Clinical Trials (IRCT201612306135N8) and clinicaltrials.gov (NCT05242133).

Improving brain atrophy quantification with deep learning from automated labels using tissue similarity priors

Brain atrophy measurements derived from magnetic resonance imaging (MRI) are a promising marker for the diagnosis and prognosis of neurodegenerative pathologies such as Alzheimer's disease or multiple sclerosis. However, its use in individualized assessments is currently discouraged due to a series of technical and biological issues. In this work, we present a deep learning pipeline for segmentation-based brain atrophy quantification that improves upon the automated labels of the reference method from which it learns. This goal is achieved through tissue similarity regularization that exploits the a priori knowledge that scans from the same subject made within a short interval must have similar tissue volumes. To train the presented pipeline, we use unlabeled pairs of T1-weighted MRI scans having a tissue similarity prior, and generate the target brain tissue segmentations in a fully automated manner using the fsl_anat pipeline implemented in the FMRIB Software Library (FSL). Tissue similarity regularization is enforced during training through a weighted loss term that penalizes tissue volume differences between short-interval scan pairs from the same subject. In inference, the pipeline performs end-to-end skull stripping and brain tissue segmentation from a single T1-weighted MRI scan in its native space, i.e., without performing image interpolation. For longitudinal evaluation, each image is independently segmented first, and then measures of change are computed. We evaluate the presented pipeline in two different MRI datasets, MIRIAD and ADNI1, which have longitudinal and short-interval imaging from healthy controls (HC) and Alzheimer's disease (AD) subjects. In short-interval scan pairs, tissue similarity regularization reduces the quantification error and improves the consistency of measured tissue volumes. In the longitudinal case, the proposed pipeline shows reduced variability of atrophy measures and higher effect sizes of differences in annualized rates between HC and AD subjects. Our pipeline obtains a Cohen's d effect size of d=2.07 on the MIRIAD dataset, an increase from the reference pipeline used to train it (d=1.01), and higher than that of SIENA (d=1.73), a well-known state-of-the-art approach. In the ADNI1 dataset, the proposed pipeline improves its effect size (d=1.37) with respect to the reference pipeline (d=0.80) and surpasses SIENA (d=1.33). The proposed data-driven deep learning regularization reduces the biases and systematic errors learned from the reference segmentation method, which is used to generate the training targets. Improving the accuracy and reliability of atrophy quantification methods is essential to unlock brain atrophy as a diagnostic and prognostic marker in neurodegenerative pathologies.

Advanced Brain Imaging in Central Nervous System Demyelinating Diseases

In recent decades, advances in neuroimaging have profoundly transformed our comprehension of central nervous system demyelinating diseases. Remarkable technological progress has enabled the integration of cutting-edge acquisition and postprocessing techniques, proving instrumental in characterizing subtle focal changes, diffuse microstructural alterations, and macroscopic pathologic processes. This review delves into state-of-the-art modalities applied to multiple sclerosis, neuromyelitis optica spectrum disorders, and myelin oligodendrocyte glycoprotein antibody-associated disease. Furthermore, it explores how this dynamic landscape holds significant promise for the development of effective and personalized clinical management strategies, encompassing support for differential diagnosis, prognosis, monitoring treatment response, and patient stratification.

Association of Spinal Cord Atrophy and Brain Paramagnetic Rim Lesions With Progression Independent of Relapse Activity in People With MS

BACKGROUND AND OBJECTIVES

Progression independent of relapse activity (PIRA) is a crucial determinant of overall disability accumulation in multiple sclerosis (MS). Accelerated brain atrophy has been shown in patients experiencing PIRA. In this study, we assessed the relation between PIRA and neurodegenerative processes reflected by (1) longitudinal spinal cord atrophy and (2) brain paramagnetic rim lesions (PRLs). Besides, the same relationship was investigated in progressive MS (PMS). Last, we explored the value of cross-sectional brain and spinal cord volumetric measurements in predicting PIRA.

METHODS

From an ongoing multicentric cohort study, we selected patients with MS with (1) availability of a susceptibility-based MRI scan and (2) regular clinical and conventional MRI follow-up in the 4 years before the susceptibility-based MRI. Comparisons in spinal cord atrophy rates (explored with linear mixed-effect models) and PRL count (explored with negative binomial regression models) were performed between: (1) relapsing-remitting (RRMS) and PMS phenotypes and (2) patients experiencing PIRA and patients without confirmed disability accumulation (CDA) during follow-up (both considering the entire cohort and the subgroup of patients with RRMS). Associations between baseline MRI volumetric measurements and time to PIRA were explored with multivariable Cox regression analyses.

RESULTS

In total, 445 patients with MS (64.9% female; mean [SD] age at baseline 45.0 [11.4] years; 11.2% with PMS) were enrolled. Compared with patients with RRMS, those with PMS had accelerated cervical cord atrophy (mean difference in annual percentage volume change [MD-APC] -1.41; p = 0.004) and higher PRL load (incidence rate ratio [IRR] 1.93; p = 0.005). Increased spinal cord atrophy (MD-APC -1.39; p = 0.0008) and PRL burden (IRR 1.95; p = 0.0008) were measured in patients with PIRA compared with patients without CDA; such differences were also confirmed when restricting the analysis to patients with RRMS. Baseline volumetric measurements of the cervical cord, whole brain, and cerebral cortex significantly predicted time to PIRA (all p ≤ 0.002).

DISCUSSION

Our results show that PIRA is associated with both increased spinal cord atrophy and PRL burden, and this association is evident also in patients with RRMS. These findings further point to the need to develop targeted treatment strategies for PIRA to prevent irreversible neuroaxonal loss and optimize long-term outcomes of patients with MS.

Differences in Brain Atrophy Pattern between People with Multiple Sclerosis and Systemic Diseases with Central Nervous System Involvement Based on Two-Dimensional Linear Measures

Conventional brain magnetic resonance imaging (MRI) in systemic diseases with central nervous system involvement (SDCNS) may imitate MRI findings of multiple sclerosis (MS). In order to better describe the MRI characteristics of these conditions, in our study we assessed brain volume parameters in MS (n = 58) and SDCNS (n = 41) patients using two-dimensional linear measurements (2DLMs): bicaudate ratio (BCR), corpus callosum index (CCI) and width of third ventricle (W3V). In SDCNS patients, all 2DLMs were affected by age (CCI p = 0.005, BCR p < 0.001, W3V p < 0.001, respectively), whereas in MS patients only BCR and W3V were (p = 0.001 and p = 0.015, respectively). Contrary to SDCNS, in the MS cohort BCR and W3V were associated with T1 lesion volume (T1LV) (p = 0.020, p = 0.009, respectively) and T2 lesion volume (T2LV) (p = 0.015, p = 0.009, respectively). CCI was associated with T1LV in the MS cohort only (p = 0.015). Moreover, BCR was significantly higher in the SDCNS group (p = 0.01) and CCI was significantly lower in MS patients (p = 0.01). The best predictive model to distinguish MS and SDCNS encompassed gender, BCR and T2LV as the explanatory variables (sensitivity 0.91; specificity 0.68; AUC 0.86). Implementation of 2DLMs in the brain MRI analysis of MS and SDCNS patients allowed for the identification of diverse patterns of local brain atrophy in these clinical conditions.

Optical coherence tomography versus other biomarkers: Associations with physical and cognitive disability in multiple sclerosis

BACKGROUND

Optical coherence tomography (OCT) is a biomarker of neuroaxonal loss in multiple sclerosis (MS).

OBJECTIVE

The objective was to assess the relative role of OCT, next to magnetic resonance imaging (MRI) and serum markers of disability in MS.

METHODS

A total of 100 patients and 52 controls underwent OCT to determine peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell-inner plexiform layers (GCIPL). Serum neurofilament light chain (sNfL), total lesion volume (TLV), and brain parenchymal fraction (BPF) were also assessed. The associations of OCT with disability were examined in linear regression models with correction for age, vision, and education.

RESULTS

In patients, pRNFL was associated with the Symbol Digit Modalities Test (SDMT; p = 0.030). In the multivariate analysis including sNfL and MRI measures, pRNFL (β = 0.19, p = 0.044) and TLV (β = -0.24, p = 0.023) were the only markers associated with the SDMT. pRNFL (p < 0.001) and GCIPL (p < 0.001) showed associations with the Expanded Disability Status Scale (EDSS). In the multivariate analysis, GCIPL showed the strongest association with the EDSS (β = -0.32, p < 0.001) followed by sNfL (β = 0.18, p = 0.024).

CONCLUSION

The associations of OCT measures with cognitive and physical disability were independent of serum and brain MRI markers of neuroaxonal loss. OCT can be an important tool for stratification in MS, while longitudinal studies using combinations of biomarkers are warranted.

Feasibility of detecting atrophy relevant for disability and cognition in multiple sclerosis using 3D-FLAIR

BACKGROUND AND OBJECTIVES

Disability and cognitive impairment are known to be related to brain atrophy in multiple sclerosis (MS), but 3D-T1 imaging required for brain volumetrics is often unavailable in clinical protocols, unlike 3D-FLAIR. Here our aim was to investigate whether brain volumes derived from 3D-FLAIR images result in similar associations with disability and cognition in MS as do those derived from 3D-T1 images.

METHODS

3T-MRI scans of 329 MS patients and 76 healthy controls were included in this cross-sectional study. Brain volumes were derived using FreeSurfer on 3D-T1 and compared with brain volumes derived with SynthSeg and SAMSEG on 3D-FLAIR. Relative agreement was evaluated by calculating the intraclass correlation coefficient (ICC) of the 3D-T1 and 3D-FLAIR volumes. Consistency of relations with disability and average cognition was assessed using linear regression, while correcting for age and sex. The findings were corroborated in an independent validation cohort of 125 MS patients.

RESULTS

The ICC between volume measured with FreeSurfer and those measured on 3D-FLAIR for brain, ventricle, cortex, total deep gray matter and thalamus was above 0.74 for SAMSEG and above 0.91 for SynthSeg. Worse disability and lower average cognition were similarly associated with brain (adj. R2 = 0.24-0.27, p < 0.01; adj. R2 = 0.26-0.29, p < 0.001) ventricle (adj. R2 = 0.27-0.28, p < 0.001; adj. R2 = 0.19-0.20, p < 0.001) and deep gray matter volumes (adj. R2 = 0.24-0.28, p < 0.001; adj. R2 = 0.27-0.28, p < 0.001) determined with all methods, except for cortical volumes derived from 3D-FLAIR.

DISCUSSION

In this cross-sectional study, brain volumes derived from 3D-FLAIR and 3D-T1 show similar relationships to disability and cognitive dysfunction in MS, highlighting the potential of these techniques in clinical datasets.

Neurodegeneration and its potential markers in the diagnosing of secondary progressive multiple sclerosis. A review

Approximately 70% of relapsing-remitting multiple sclerosis (RRMS) patients will develop secondary progressive multiple sclerosis (SPMS) within 10-15 years. This progression is characterized by a gradual decline in neurological functionality and increasing limitations of daily activities. Growing evidence suggests that both inflammation and neurodegeneration are associated with various pathological processes throughout the development of MS; therefore, to delay disease progression, it is critical to initiate disease-modifying therapy as soon as it is diagnosed. Currently, a diagnosis of SPMS requires a retrospective assessment of physical disability exacerbation, usually over the previous 6-12 months, which results in a delay of up to 3 years. Hence, there is a need to identify reliable and objective biomarkers for predicting and defining SPMS conversion. This review presents current knowledge of such biomarkers in the context of neurodegeneration associated with MS, and SPMS conversion.

Brain Atrophy as an Outcome of Disease-Modifying Therapy for Remitting-Relapsing Multiple Sclerosis

Introduction

Currently, clinical trials of DMTs strive to determine their effect on neuroinflammation and neurodegeneration. We aimed to determine the impact of currently used DMTs on brain atrophy and disability in RRMS. The main goal of this review is to evaluate the neuroprotective potential of MS therapy and assess its impact on disability.

Methods

We performed a systematic analysis of clinical trials that used brain atrophy as an outcome or performed post hoc analysis of volumetric MRI parameters to assess the neuroprotective potential of applied therapies. Trials between 2008 and 2019 that included published results of brain parenchymal fraction (BPF) change and brain volume loss (BVL) in the period from baseline to week 96 or longer were considered.

Results

Twelve from 146 clinical trials met the inclusion criteria and were incorporated into the analysis. DMTs that presented a large reduction in BVL also exhibited robust effects on clinical disability worsening, e.g., alemtuzumab with a 42% risk reduction in 6-month confirmed disability accumulation (p = 0.0084), ocrelizumab with a 40% risk reduction in 6-month confirmed disability progression (p = 0.003), and other DMTs (cladribine and teriflunomide) with moderate influence on brain atrophy were also associated with a marked impact on disability worsening. Dimethyl fumarate (DEFINE) and fingolimod (FREEDOMS I) initially exhibited significant effect on BVL; however, this effect was not confirmed in further clinical trials: CONFIRM and FREEDOMS II, respectively. Peg-IFN-β1a shows a modest effect on BVL and disability worsening.

Conclusion

Our results show that BVL in one of the components of clinical disability worsening, together with other variables (lesion volume and annualized relapse rate). Standardization of atrophy measurement technique as well as harmonization of disability worsening and progression criteria in further clinical trials are of utmost importance as they enable a reliable comparison of neuroprotective potential of DMTs.

Comparison of recent updates in genetics, immunology, biomarkers, and neuroimaging of primary-progressive and relapsing-remitting multiple sclerosis and the role of ocrelizumab in the management of their refractory cases

Background

Primary-progressive multiple sclerosis (PPMS) and relapsing-remitting multiple sclerosis (RRMS) are two frequent multiple sclerosis (MS) subtypes that involve 10%-15% of patients. PPMS progresses slowly and is diagnosed later in life. Both subtypes are influenced by genetic and environmental factors such as smoking, obesity, and vitamin D insufficiency. Although there is no cure, ocrelizumab can reduce symptoms and delay disease development. RRMS is an autoimmune disease that causes inflammation, demyelination, and disability. Early detection, therapy, and lifestyle changes are critical. This study delves into genetics, immunology, biomarkers, neuroimaging, and the usefulness of ocrelizumab in the treatment of refractory patients of PPMS.

Method

In search of published literature providing up-to-date information on PPMS and RRMS, this review conducted numerous searches in databases such as PubMed, Google Scholar, MEDLINE, and Scopus. We looked into genetics, immunology, biomarkers, current breakthroughs in neuroimaging, and the role of ocrelizumab in refractory cases.

Results

Our comprehensive analysis found considerable advances in genetics, immunology, biomarkers, neuroimaging, and the efficacy of ocrelizumab in the treatment of refractory patients.

Conclusion

Early detection, timely intervention, and the adoption of lifestyle modifications play pivotal roles in enhancing treatment outcomes. Notably, ocrelizumab has demonstrated potential in symptom control and mitigating the rate of disease advancement, further underscoring its clinical significance in the management of MS.

Optical coherence tomography reflects clinically relevant gray matter damage in patients with multiple sclerosis

BACKGROUND

Retinal degeneration leading to optical coherence tomography (OCT) changes is frequent in patients with multiple sclerosis (PwMS).

OBJECTIVE

To investigate associations among OCT changes, MRI measurements of global and regional brain volume loss, and physical and cognitive impairment in PwMS.

METHODS

95 PwMS and 52 healthy controls underwent OCT and MRI examinations. Mean peripapillary retinal nerve fiber layer (pRNFL) thickness and ganglion cell/inner plexiform layer (GCIPL) volume were measured. In PwMS disability was quantified with the Expanded Disability Status Scale (EDSS) and Symbol Digit Modalities Test (SDMT). Associations between OCT, MRI, and clinical measures were investigated with multivariable regression models.

RESULTS

In PwMS, pRNFL and GCIPL were associated with the volume of whole brain (p < 0.04), total gray matter (p < 0.002), thalamus (p ≤ 0.04), and cerebral cortex (p ≤ 0.003) -both globally and regionally-, but not white matter. pRNFL and GCIPL were also inversely associated with T2-lesion volume (T2LV), especially in the optic radiations (p < 0.0001). The brain volumes associated with EDSS and SDMT significantly overlapped with those correlating with pRNFL and GCIPL.

CONCLUSIONS

In PwMS, pRNFL and GCIPL reflect the integrity of clinically-relevant gray matter structures, underling the value of OCT measures as markers of neurodegeneration and disability in multiple sclerosis.

Association of volumetric MRI measures and disability in MS patients of the same age: Descriptions from a birth year cohort

BACKGROUND AND OBJECTIVES

Although MRI-based markers of neuroinflammation have proven crucial for the diagnosis of multiple sclerosis (MS), predicting clinical progression with inflammation remains difficult. Neurodegenerative markers such as brain volume loss show stronger clinical (predictive) correlations, but also harbor age-related variation that must be disentangled from disease duration. In this study we investigated how clinical disability is related to volumetric MRI measures in a cohort of MS patients and healthy controls (HC) of the same age: Project Y.

METHODS

This study included 234 MS patients born in 1966 and 112 HC born between 1965 and 1967 in the Netherlands. Disability was quantified using the expanded disability status scale (EDSS), nine hole peg test (9HPT), and timed 25 foot walking test (T25FWT). Volumes were quantified on 3T MRI as normalized whole brain (NBV) and regional gray matter (GM) volumes using the same scanner and MRI protocol: cortical (normalized cortical gray matter volume; NCGMV), deep (NDGMV), thalamic (NThalV), and cerebellar (NCbV) GM volumes. In addition, mean upper cervical cord area (MUCCA), white matter lesion volume (LV), and spinal cord lesions were assessed. These measures were compared between patients and HC, and related to disability measures using linear regression.

RESULTS

Mean age of people with MS (PwMS) was 52.8 years (SD 0.9) and median disease duration 15.8 years (IQR 8.7-24.8). All global and regional brain measures were lower in MS patients compared to HC. Univariate regression models showed that NDGMV (β = -0.20) and MUCCA (β = -0.38) were most strongly related to the EDSS in all PwMS. After subtype stratification, MUCCA was most strongly related to the EDSS (β = -0.60) and 9HPT (β = -0.55) in secondary progressive PwMS. Multivariate regression models demonstrated that in all PwMS, the EDSS was best explained by lower MUCCA, longer disease durations and a progressive disease course (adjusted-R (Sastre-Garriga et al., 2017) = 0.26, p < 0.001). MUCCA was a consistent correlate in separate models of the EDSS for all PwMS, relapsing and progressive onset PwMS. The 9HPT (adjusted-R (Sastre-Garriga et al., 2017) = 0.20, p < 0.001) was best explained by lower MUCCA, higher LV and pack years, while lower limb disability (adjusted-R (Sastre-Garriga et al., 2017) = 0.11, p < 0.001) was best explained by lower MUCCA, progressive onset MS and female sex.

DISCUSSION

Our results indicate that in a cohort unbiased by age differences, spinal cord and deep gray matter volumes best related to physical disability. Our results support the use of these measures in clinical practice and trials.

Correlation of brain segmental volume changes with clinical parameters: a longitudinal study in multiple sclerosis patients

OBJECTIVE

 To measure the cranial volume differences from 15 different parts in the follow-up of relapsing-remitting multiple sclerosis (RRMS) patients and correlate them with clinical parameters.

METHODS

 Forty-seven patients with RRMS were included in the study. Patients were grouped into two categories; low Expanded Disability Status Scale (EDSS) (< 3; group 1), and moderate-high EDSS (≥ 3; group 2). Patients were evaluated with Beck Depression Inventory (BDI), Montreal Cognitive Assessment (MOCA), Symbol Digit Modalities Test (SDMT), Fatigue Severity Scale (FSS), and calculated Annualized Relapse Rate (ARR) scores. Magnetic resonance imaging (MRI) was performed with a 1.5T MRI device (Magnetom AERA, Siemens, Erlangen, Germany) twice in a 1-year period. Volumetric analysis was performed by a free, automated, online MRI brain volumetry software. The differences in volumetric values between the two MRI scans were calculated and correlated with the demographic and clinical parameters of the patients.

RESULTS

 The number of attacks, disease duration, BDI, and FSS scores were higher in group 2; SDMT was higher in group 1. As expected, volumetric analyses have shown volume loss in total cerebral white matter in follow-up patients (p < 0.001). In addition, putaminal volume loss was related to a higher number of attacks. Besides, a negative relation between FSS with total amygdala volumes, a link between atrophy of globus pallidus and ARR, and BDI scores was found with the aid of network analysis.

CONCLUSIONS

 Apart from a visual demonstration of volume loss, cranial MRI with volumetric analysis has a great potential for revealing covert links between segmental volume changes and clinical parameters.

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.

Commercial volumetric MRI reporting tools in multiple sclerosis: a systematic review of the evidence

PURPOSE

MRI is integral to the diagnosis of multiple sclerosis (MS) and is important for clinical prognostication. Quantitative volumetric reporting tools (QReports) can improve the accuracy and objectivity of MRI-based assessments. Several QReports are commercially available; however, validation can be difficult to establish and does not currently follow a common pathway. To aid evidence-based clinical decision-making, we performed a systematic review of commercial QReports for use in MS including technical details and published reports of validation and in-use evaluation.

METHODS

We categorized studies into three types of testing: technical validation, for example, comparison to manual segmentation, clinical validation by clinicians or interpretation of results alongside clinician-rated variables, and in-use evaluation, such as health economic assessment.

RESULTS

We identified 10 companies, which provide MS lesion and brain segmentation and volume quantification, and 38 relevant publications. Tools received regulatory approval between 2006 and 2020, contextualize results to normative reference populations, ranging from 620 to 8000 subjects, and require T1- and T2-FLAIR-weighted input sequences for longitudinal assessment of whole-brain volume and lesions. In MS, six QReports provided evidence of technical validation, four companies have conducted clinical validation by correlating results with clinical variables, only one has tested their QReport by clinician end-users, and one has performed a simulated in-use socioeconomic evaluation.

CONCLUSION

We conclude that there is limited evidence in the literature regarding clinical validation and in-use evaluation of commercial MS QReports with a particular lack of clinician end-user testing. Our systematic review provides clinicians and institutions with the available evidence when considering adopting a quantitative reporting tool for MS.

Cognitive impairment in paediatric onset multiple sclerosis and its relation to thalamic volume and cortical thickness of temporal lobe by magnetic resonance imaging

Background

Pediatric onset multiple sclerosis (POMS), defined as an age at onset younger than 18 years, which occurs in 5% of patients with MS. cognitive dysfunction is one of the prominent disabling sequelae of Multiple sclerosis. Brain volumetric studies by magnetic resonance images revealed the decline of whole and regional brain volumes along the disease course. This work aimed to investigate the relationship between cognitive impairment in pediatric MS patients with thalamic atrophy and cortical thickness of temporal lobe. This study included 50 patients who were diagnosed as POMS and 50 healthy control participants matched for age and sex. Both groups were compared for volumetric measurements of thalamic volumes and temporal lobes cortical thickness using a computerized program called FreeSurfer.MS group was evaluated for cognitive dysfunction using Arabic version of fifth edition of Standford–Benit test. A correlation between volumetric results and neuropsychological evaluation of MS group was done.

Results

Our study showed that the MS group has the lowest value regarding their thalamic volumes and their cortical thickness of temporal lobes in relation to the healthy control group, while there was a significant relation between cognitive impairment and decrease in thalamic volume and specific areas in cortical thickness, such as superior temporal thickness, middle temporal thickness, inferior temporal thickness, fusiform thickness and para hippocampal thickness of temporal lobe in pediatric onset MS patients.

Conclusions

POMS affects specific brain areas such as thalamus and cortical thickness of temporal lobes regarding their volume and thickness which influence the neuropsychological evaluation detected by Standford–Benit test.

Association of Brain Atrophy With Disease Progression Independent of Relapse Activity in Patients With Relapsing Multiple Sclerosis

Importance

The mechanisms driving neurodegeneration and brain atrophy in relapsing multiple sclerosis (RMS) are not completely understood.

Objective

To determine whether disability progression independent of relapse activity (PIRA) in patients with RMS is associated with accelerated brain tissue loss.

Design, Setting, and Participants

In this observational, longitudinal cohort study with median (IQR) follow-up of 3.2 years (2.0-4.9), data were acquired from January 2012 to September 2019 in a consortium of tertiary university and nonuniversity referral hospitals. Patients were included if they had regular clinical follow-up and at least 2 brain magnetic resonance imaging (MRI) scans suitable for volumetric analysis. Data were analyzed between January 2020 and March 2021.

Exposures

According to the clinical evolution during the entire observation, patients were classified as those presenting (1) relapse activity only, (2) PIRA episodes only, (3) mixed activity, or (4) clinical stability.

Main Outcomes and Measures

Mean difference in annual percentage change (MD-APC) in brain volume/cortical thickness between groups, calculated after propensity score matching. Brain atrophy rates, and their association with the variables of interest, were explored with linear mixed-effect models.

Results

Included were 1904 brain MRI scans from 516 patients with RMS (67.4% female; mean [SD] age, 41.4 [11.1] years; median [IQR] Expanded Disability Status Scale score, 2.0 [1.5-3.0]). Scans with insufficient quality were excluded (n = 19). Radiological inflammatory activity was associated with increased atrophy rates in several brain compartments, while an increased annualized relapse rate was linked to accelerated deep gray matter (GM) volume loss. When compared with clinically stable patients, patients with PIRA had an increased rate of brain volume loss (MD-APC, -0.36; 95% CI, -0.60 to -0.12; P = .02), mainly driven by GM loss in the cerebral cortex. Patients who were relapsing presented increased whole brain atrophy (MD-APC, -0.18; 95% CI, -0.34 to -0.02; P = .04) with respect to clinically stable patients, with accelerated GM loss in both cerebral cortex and deep GM. No differences in brain atrophy rates were measured between patients with PIRA and those presenting relapse activity.

Conclusions and Relevance

Our study shows that patients with RMS and PIRA exhibit accelerated brain atrophy, especially in the cerebral cortex. These results point to the need to recognize the insidious manifestations of PIRA in clinical practice and to further evaluate treatment strategies for patients with PIRA in clinical trials.

Qualitative and Quantitative Comparison of Hippocampal Volumetric Software Applications: Do All Roads Lead to Rome?

Brain volumetric software is increasingly suggested for clinical routine. The present study quantifies the agreement across different software applications. Ten cases with and ten gender- and age-adjusted healthy controls without hippocampal atrophy (median age: 70; 25–75% range: 64–77 years and 74; 66–78 years) were retrospectively selected from a previously published cohort of Alzheimer’s dementia patients and normal ageing controls. Hippocampal volumes were computed based on 3 Tesla T1-MPRAGE-sequences with FreeSurfer (FS), Statistical-Parametric-Mapping (SPM; Neuromorphometrics and Hammers atlases), Geodesic-Information-Flows (GIF), Similarity-and-Truth-Estimation-for-Propagated-Segmentations (STEPS), and Quantib™. MTA (medial temporal lobe atrophy) scores were manually rated. Volumetric measures of each individual were compared against the mean of all applications with intraclass correlation coefficients (ICC) and Bland–Altman plots. Comparing against the mean of all methods, moderate to low agreement was present considering categorization of hippocampal volumes into quartiles. ICCs ranged noticeably between applications (left hippocampus (LH): from 0.42 (STEPS) to 0.88 (FS); right hippocampus (RH): from 0.36 (Quantib™) to 0.86 (FS). Mean differences between individual methods and the mean of all methods [mm³] were considerable (LH: FS −209, SPM-Neuromorphometrics −820; SPM-Hammers −1474; Quantib™ −680; GIF 891; STEPS 2218; RH: FS −232, SPM-Neuromorphometrics −745; SPM-Hammers −1547; Quantib™ −723; GIF 982; STEPS 2188). In this clinically relevant sample size with large spread in data ranging from normal aging to severe atrophy, hippocampal volumes derived by well-accepted applications were quantitatively different. Thus, interchangeable use is not recommended.

Smouldering multiple sclerosis: the 'real MS'

Using a philosophical approach or deductive reasoning, we challenge the dominant clinico-radiological worldview that defines multiple sclerosis (MS) as a focal inflammatory disease of the central nervous system (CNS). We provide a range of evidence to argue that the 'real MS' is in fact driven primarily by a smouldering pathological disease process. In natural history studies and clinical trials, relapses and focal activity revealed by magnetic resonance imaging (MRI) in MS patients on placebo or on disease-modifying therapies (DMTs) were found to be poor predictors of long-term disease evolution and were dissociated from disability outcomes. In addition, the progressive accumulation of disability in MS can occur independently of relapse activity from early in the disease course. This scenario is underpinned by a more diffuse smouldering pathological process that may affect the entire CNS. Many putative pathological drivers of smouldering MS can be potentially modified by specific therapeutic strategies, an approach that may have major implications for the management of MS patients. We hypothesise that therapeutically targeting a state of 'no evident inflammatory disease activity' (NEIDA) cannot sufficiently prevent disability accumulation in MS, meaning that treatment should also focus on other brain and spinal cord pathological processes contributing to the slow loss of neurological function. This should also be complemented with a holistic approach to the management of other systemic disease processes that have been shown to worsen MS outcomes.

Brain Volume Loss Can Occur at the Rate of Normal Aging in Patients with Multiple Sclerosis Who Are Free from Disease Activity

Multiple sclerosis (MS) is a chronic inflammatory demyelinating and degenerative disorder of the central nervous system. Accelerated brain volume loss (BVL) has emerged as a promising magnetic resonance imaging marker (MRI) of neurodegeneration, correlating with present and future clinical disability. We have systematically selected MS patients fulfilling ‘no evidence of disease activity-3′ (NEDA-3) criteria under high-efficacy disease-modifying treatment (DMT) from the database of two Belgian MS centers. BVL between both MRI scans demarcating the NEDA-3 period was assessed and compared with a group of prospectively recruited healthy volunteers who were matched for age and gender. Annualized whole brain volume percentage change was similar between 29 MS patients achieving NEDA-3 and 24 healthy controls (−0.25 ± 0.49 versus −0.24 ± 0.20, p = 0.9992; median follow-up 21 versus 33 months; respectively). In contrast, we found a mean BVL increase of 72%, as compared with the former, in a second control group of MS patients (n = 21) whom had been excluded from the NEDA-3 group due to disease activity (p = 0.1371). Our results suggest that neurodegeneration in MS can slow down to the rate of normal aging once inflammatory disease activity has been extinguished and advocate for an early introduction of high-efficacy DMT to reduce the risk of future clinical disability.

Synaptic Loss in Multiple Sclerosis: A Systematic Review of Human Post-mortem Studies

Background: Gray matter pathology plays a central role in the progression of multiple sclerosis (MS). The occurrence of synaptic loss appears to be important but, to date, still poorly investigated aspect of MS pathology. In this systematic review, we drew from the recent knowledge about synaptic loss in human post-mortem studies. Methods: We conducted a systematic search with PubMed to identify relevant publications. Publications available from15 June 2021 were taken into account. We selected human post-mortem studies that quantitatively assessed the synapse number in MS tissue. Results: We identified 14 relevant publications out of which 9 reported synaptic loss in at least one investigated subregion. The most commonly used synaptic marker was synaptophysin; non-etheless, we found substantial differences in the methodology and the selection of reference tissue. Investigated regions included the cortex, the hippocampus, the cerebellum, the thalamus, and the spinal cord. Conclusion: Synaptic loss seems to take place throughout the entire central nervous system. However, the results are inconsistent, probably due to differences in the methodology. Moreover, synaptic loss appears to be a dynamic process, and thus the nature of this pathology might be captured using in vivo synaptic density measurements.

Neurofilament light chain as a biomarker for diagnosis of multiple sclerosis

The treatments for multiple sclerosis (MS) have improved over the past 25 years, but now the main question for physicians is deciding who should receive treatment, for how long, and when to switch to other options. These decisions are typically based on treatment tolerance and a reasonable expectation of long-term efficacy. A significant unmet need is the lack of accurate laboratory measurements for diagnosis, and monitoring of treatment response, including deterioration and disease progression. There are few validated biomarkers for MS, and in practice, physicians employ two biomarkers discovered fifty years ago for MS diagnosis, often in combination with MRI scans. These biomarkers are intrathecal IgG and oligoclonal bands in the CSF (cerebrospinal fluid). Neurofilament light chain (NfL) is a relatively new biomarker for MS diagnosis and follow up. Neurofilaments are neuron-specific cytoskeleton proteins that can be measured in various body compartments. NfL is a new biomarker for MS that can be measured in serum samples, but this still needs further study to specify the laboratory cut-off values in clinical practice. In the present review we discuss the evidence for NfL as a reliable biomarker for the early detection and management of MS. Moreover, we highlight the correlation between MRI and NfL, and ask whether they can be combined.

Clinical and Paraclinical Biomarkers and the Hitches to Assess Conversion to Secondary Progressive Multiple Sclerosis: A Systematic Review

Conversion to secondary progressive (SP) course is the decisive factor for long-term prognosis in relapsing multiple sclerosis (MS), generally considered the clinical equivalent of progressive MS-associated neuroaxonal degeneration. Evidence is accumulating that both inflammation and neurodegeneration are present along a continuum of pathologic processes in all phases of MS. While inflammation is the prominent feature in early stages, its quality changes and relative importance to disease course decreases while neurodegenerative processes prevail with ongoing disease. Consequently, anti-inflammatory disease-modifying therapies successfully used in relapsing MS are ineffective in SPMS, whereas specific treatment for the latter is increasingly a focus of MS research. Therefore, the prevention, but also the (anticipatory) diagnosis of SPMS, is of crucial importance. The problem is that currently SPMS diagnosis is exclusively based on retrospectively assessing the increase of overt physical disability usually over the past 6–12 months. This inevitably results in a delay of diagnosis of up to 3 years resulting in periods of uncertainty and, thus, making early therapy adaptation to prevent SPMS conversion impossible. Hence, there is an urgent need for reliable and objective biomarkers to prospectively predict and define SPMS conversion. Here, we review current evidence on clinical parameters, magnetic resonance imaging and optical coherence tomography measures, and serum and cerebrospinal fluid biomarkers in the context of MS-associated neurodegeneration and SPMS conversion. Ultimately, we discuss the necessity of multimodal approaches in order to approach objective definition and prediction of conversion to SPMS.

Cortical surface thickness, subcortical volumes and disability between races in relapsing-remitting multiple sclerosis

BACKGROUND

The interplay between cortical surface thickness (CTh), subcortical volumes (SCV) and disability in patients with relapsing remitting multiple sclerosis (RRMS) is still not clear.

OBJECTIVE

To examine the relationship between CTh, SCV, and disability and investigate differences in CTh, SCV and disability between African Americans (AA) and Caucasian Americans (CA).

METHODS

Sixty-five RRMS (33AA, 32 CA) participants underwent Expanded Disability Status Scale and Multiple Sclerosis Functional Composite (MSFC) assessments, including timed 25-foot walk (T25FW), nine-hole peg test (9HPT) on dominant (D) and non-dominant hand (ND) and paced auditory serial addition test (PASAT-3). Symbol digit modalities test (SDMT) was also administered. All participants underwent 3T brain MRI. CTh was measured in the Frontal (FA), Parietal (PA), Temporal (TA), Occipital (OA), Cingulate (CA), and Global (GA) cortical surface areas (CSA). SCV measurements included Thalamus (TV), Caudate (CV), Putamen (PV), Pallidum (PaV), Hippocampus (HV), Amygdala (AV), Accumbens (AcV), Brain Stem (BSV), and Deep Gray Matter Total Volume (DGMTV). A general linear model with multivariate analysis (MANOVA) was used to determine the differences between the two cohorts (SPSS vs 25). Spearman rank correlation analysis was performed to investigate the relationship between CTh and MSFC.

RESULTS

AA have significantly decreased FA, PA, TA, GA CTh compared to CA (p = 0.004, p = 0.018, p = 0.013, p = 0.015, respectively). SCV measurements were not significantly different. Only in CA, the MSFC measures correlate significantly with regional CSA CTh. In both races and in the entire group, T25FW correlates with TV, PV, AV, AcV and DGMTV (p < 0.05). Only in AA and the entire cohort, PASAT-3 correlates with TV and AcV(p = 0.041, p = 0.006, p = 0.006, p = 0.000 respectively).

CONCLUSIONS

Differences in CSA CTh reinforce the different disease pathobiology between AA and CA. Regional CTh may represent a useful biomarker related to multi-domain disability only in CA, while in AA DGM injury might be a more important contributor to disability. Longitudinal, large-scale studies are warranted to confirm our findings.

Physical activity may contribute to brain health in multiple sclerosis: An MR volumetric and spectroscopy study

BACKGROUND AND PURPOSE

Physical activity may represent a disease-modifying therapy in persons with multiple sclerosis (pwMS). To date, there is limited research regarding mechanisms based on brain imaging for understanding the beneficial effects of physical activity in pwMS. This study examined the relationship between physical activity levels and thalamic and hippocampal volumes and brain metabolism in pwMS.

METHODS

The sample of 52 pwMS (37.3 ± 9.6 years of age; 35 females, 17 males) underwent a combination of volumetric magnetic resonance imaging and magnetic resonance spectroscopy. Current and lifetime physical activity were assessed using actigraphy and the adapted version of the Historical Activity Questionnaire, respectively.

RESULTS

Positive associations were observed between both actigraphy and self-reported levels of moderate-to-vigorous physical activity (MVPA) and thalamic and hippocampal volumes. Regarding brain metabolism, actigraphy and self-reported levels of MVPA were positively associated with higher hippocampal and thalamic levels of N-acetylaspartate/creatine ratio (NAA/Cr: marker of neural integrity and cell energy state).

CONCLUSIONS

This study provides novel evidence for a positive association between physical activity and thalamic and hippocampal volume and metabolism in pwMS. These findings support the hypothesis that physical activity, particularly MVPA, may serve as a disease-modifying treatment by improving brain health in pwMS.

Deciphering Multiple Sclerosis Progression

Multiple sclerosis (MS) is primarily an inflammatory and degenerative disease of the central nervous system, triggered by unknown environmental factors in patients with predisposing genetic risk profiles. The prevention of neurological disability is one of the essential goals to be achieved in a patient with MS. However, the pathogenic mechanisms driving the progressive phase of the disease remain unknown. It was described that the pathophysiological mechanisms associated with disease progression are present from disease onset. In daily practice, there is a lack of clinical, radiological, or biological markers that favor an early detection of the disease's progression. Different definitions of disability progression were used in clinical trials. According to the most descriptive, progression was defined as a minimum increase in the Expanded Disability Status Scale (EDSS) of 1.5, 1.0, or 0.5 from a baseline level of 0, 1.0–5.0, and 5.5, respectively. Nevertheless, the EDSS is not the most sensitive scale to assess progression, and there is no consensus regarding any specific diagnostic criteria for disability progression. This review document discusses the current pathophysiological concepts associated with MS progression, the different measurement strategies, the biomarkers associated with disability progression, and the available pharmacologic therapeutic approaches.

FLAIR-only joint volumetric analysis of brain lesions and atrophy in clinically isolated syndrome (CIS) suggestive of multiple sclerosis

Background

MRI assessment in multiple sclerosis (MS) focuses on the presence of typical white matter (WM) lesions. Neurodegeneration characterised by brain atrophy is recognised in the research field as an important prognostic factor. It is not routinely reported clinically, in part due to difficulty in achieving reproducible measurements. Automated MRI quantification of WM lesions and brain volume could provide important clinical monitoring data. In general, lesion quantification relies on both T1 and FLAIR input images, while tissue volumetry relies on T1. However, T1-weighted scans are not routinely included in the clinical MS protocol, limiting the utility of automated quantification.

Objectives

We address an aspect of this important translational challenge by assessing the performance of FLAIR-only lesion and brain segmentation, against a conventional approach requiring multi-contrast acquisition. We explore whether FLAIR-only grey matter (GM) segmentation yields more variability in performance compared with two-channel segmentation; whether this is related to field strength; and whether the results meet a level of clinical acceptability demonstrated by the ability to reproduce established biological associations.

Methods

We used a multicentre dataset of subjects with a CIS suggestive of MS scanned at 1.5T and 3T in the same week. WM lesions were manually segmented by two raters, ‘manual 1′ guided by consensus reading of CIS-specific lesions and ‘manual 2′ by any WM hyperintensity. An existing brain segmentation method was adapted for FLAIR-only input. Automated segmentation of WM hyperintensity and brain volumes were performed with conventional (T1/T1 + FLAIR) and FLAIR-only methods.

Results

WM lesion volumes were comparable at 1.5T between ‘manual 2′ and FLAIR-only methods and at 3T between ‘manual 2′, T1 + FLAIR and FLAIR-only methods. For cortical GM volume, linear regression measures between conventional and FLAIR-only segmentation were high (1.5T: α = 1.029, R² = 0.997, standard error (SE) = 0.007; 3T: α = 1.019, R² = 0.998, SE = 0.006). Age-associated change in cortical GM volume was a significant covariate in both T1 (p = 0.001) and FLAIR-only (p = 0.005) methods, confirming the expected relationship between age and GM volume for FLAIR-only segmentations.

Conclusions

FLAIR-only automated segmentation of WM lesions and brain volumes were consistent with results obtained through conventional methods and had the ability to demonstrate biological effects in our study population. Imaging protocol harmonisation and validation with other MS phenotypes could facilitate the integration of automated WM lesion volume and brain atrophy analysis as clinical tools in radiological MS reporting.

Disability Improvement Is Associated with Less Brain Atrophy Development in Multiple Sclerosis

BACKGROUND AND PURPOSE

It is unknown whether deceleration of brain atrophy is associated with disability improvement in patients with MS. Our aim was to investigate whether patients with MS with disability improvement develop less brain atrophy compared with those who progress in disability or remain stable.

MATERIALS AND METHODS

We followed 980 patients with MS for a mean of 4.8 ± 2.4 years. Subjects were divided into 3 groups: progress in disability (n = 241, 24.6%), disability improvement (n = 101, 10.3%), and stable (n = 638, 65.1%) at follow-up. Disability improvement and progress in disability were defined on the basis of the Expanded Disability Status Scale score change using standardized guidelines. Stable was defined as nonoccurrence of progress in disability or disability improvement. Normalized whole-brain volume was calculated using SIENAX on 3D T1WI, whereas the lateral ventricle was measured using NeuroSTREAM on 2D-T2-FLAIR images. The percentage brain volume change and percentage lateral ventricle volume change were calculated using SIENA and NeuroSTREAM, respectively. Differences among groups were investigated using ANCOVA, adjusted for age at first MR imaging, race, T2 lesion volume, and corresponding baseline structural volume and the Expanded Disability Status Scale.

RESULTS

At first MR imaging, there were no differences among progress in disability, disability improvement, and the stable groups in whole-brain volume (P = .71) or lateral ventricle volume (P = .74). During follow-up, patients with disability improvement had the lowest annualized percentage lateral ventricle volume change (1.6% ± 2.7%) followed by patients who were stable (2.1% ± 3.7%) and had progress in disability (4.1% ± 5.5%), respectively (P < .001). The annualized percentage brain volume change values were -0.7% ± 0.7% for disability improvement, -0.8% ± 0.7% for stable, and -1.1% ± 1.1% for progress in disability (P = .001).

CONCLUSIONS

Patients with MS who improve in their clinical disability develop less brain atrophy across time compared with those who progress.

The role of the brain in the treatment of multiple sclerosis as a connectomopathy

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) causing a variety of symptoms. Although MS is recognized by the demyelinating process, the axonal injury can occur from the start of the disease and lead to neurodegenerative process in the disease. Although MS appears to damage the brain locally, the progressive and neurodegenerative nature of the disease indicate the general and global brain damage. Various studies have indicated this global damage at all areas of white and gray matter. Moreover, the earlier stages of mentioned disease can affect the structural and functional brain connections. Demyelinating lesions, which are local at first glance, lead to a global damage to the functional connections of the brain. Therefore, it seems that the brain network or brain connectome are broadly affected by this disease; therefore, MS can be referred as a connectomopathy. The drugs used in this disease all seek to suppress or regulate the immune system, and the human brain has always been considered as a therapeutic target. However, if the brain is generally involved in the disease, so the treatment should be general. In fact, the treatment process should target the connectomopathy. One of the methods that can be used to achieve the mentioned goal is attending to the role of the brain in its treatment.

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.

Visualizing the Central Nervous System: Imaging Tools for Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are autoimmune central nervous system conditions with increasing incidence and prevalence. While MS is the most frequent inflammatory CNS disorder in young adults, NMOSD is a rare disease, that is pathogenetically distinct from MS, and accounts for approximately 1% of demyelinating disorders, with the relative proportion within the demyelinating CNS diseases varying widely among different races and regions. Most immunomodulatory drugs used in MS are inefficacious or even harmful in NMOSD, emphasizing the need for a timely and accurate diagnosis and distinction from MS. Despite distinct immunopathology and differences in disease course and severity there might be considerable overlap in clinical and imaging findings, posing a diagnostic challenge for managing neurologists. Differential diagnosis is facilitated by positive serology for AQP4-antibodies (AQP4-ab) in NMOSD, but might be difficult in seronegative cases. Imaging of the brain, optic nerve, retina and spinal cord is of paramount importance when managing patients with autoimmune CNS conditions. Once a diagnosis has been established, imaging techniques are often deployed at regular intervals over the disease course as surrogate measures for disease activity and progression and to surveil treatment effects. While the application of some imaging modalities for monitoring of disease course was established decades ago in MS, the situation is unclear in NMOSD where work on longitudinal imaging findings and their association with clinical disability is scant. Moreover, as long-term disability is mostly attack-related in NMOSD and does not stem from insidious progression as in MS, regular follow-up imaging might not be useful in the absence of clinical events. However, with accumulating evidence for covert tissue alteration in NMOSD and with the advent of approved immunotherapies the role of imaging in the management of NMOSD may be reconsidered. By contrast, MS management still faces the challenge of implementing imaging techniques that are capable of monitoring progressive tissue loss in clinical trials and cohort studies into treatment algorithms for individual patients. This article reviews the current status of imaging research in MS and NMOSD with an emphasis on emerging modalities that have the potential to be implemented in clinical practice.

Deep-Learning-Based Neural Tissue Segmentation of MRI in Multiple Sclerosis: Effect of Training Set Size

BACKGROUND

The dependence of deep-learning (DL)-based segmentation accuracy of brain MRI on the training size is not known.

PURPOSE

To determine the required training size for a desired accuracy in brain MRI segmentation in multiple sclerosis (MS) using DL.

STUDY TYPE

Retrospective analysis of MRI data acquired as part of a multicenter clinical trial.

STUDY POPULATION

In all, 1008 patients with clinically definite MS.

FIELD STRENGTH/SEQUENCE

MRIs were acquired at 1.5T and 3T scanners manufactured by GE, Philips, and Siemens with dual turbo spin echo, FLAIR, and T1 -weighted turbo spin echo sequences.

ASSESSMENT

Segmentation results using an automated analysis pipeline and validated by two neuroimaging experts served as the ground truth. A DL model, based on a fully convolutional neural network, was trained separately using 16 different training sizes. The segmentation accuracy as a function of the training size was determined. These data were fitted to the learning curve for estimating the required training size for desired accuracy.

STATISTICAL TESTS

The performance of the network was evaluated by calculating the Dice similarity coefficient (DSC), and lesion true-positive and false-positive rates.

RESULTS

The DSC for lesions showed much stronger dependency on the sample size than gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). When the training size was increased from 10 to 800 the DSC values varied from 0.00 to 0.86 ± 0.016 for T2 lesions, 0.87 ± 009 to 0.94 ± 0.004 for GM, 0.86 ± 0.08 to 0.94 ± 0.005 for WM, and 0.91 ± 0.009 to 0.96 ± 0.003 for CSF.

DATA CONCLUSION

Excellent segmentation was achieved with a training size as small as 10 image volumes for GM, WM, and CSF. In contrast, a training size of at least 50 image volumes was necessary for adequate lesion segmentation.

LEVEL OF EVIDENCE

1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1487-1496.

Conversion of diffusely abnormal white matter to focal lesions is linked to progression in secondary progressive multiple sclerosis

Background:

Diffusely abnormal white matter (DAWM) regions are observed in magnetic resonance images of secondary progressive multiple sclerosis (SPMS) patients. However, their role in clinical progression is still not established.

Objectives:

To characterize the longitudinal volumetric and intensity evolution of DAWM and focal white matter lesions (FWML) and assess their associations with clinical outcomes and progression in SPMS.

Methods:

Data include 589 SPMS participants followed up for 3 years (3951 time points). FWML and DAWM were automatically segmented. Screening DAWM volumes that transformed into FWML at the last visit (DAWM-to-FWML) and normalized T1-weighted intensities (indicating severity of damage) in those voxels were calculated.

Results:

FWML volume increased and DAWM volume decreased with an increase in disease duration ( p < 0.001). The Expanded Disability Status Scale (EDSS) was positively associated with FWML volumes ( p = 0.002), but not with DAWM. DAWM-to-FWML volume was higher in patients who progressed (2.75 cm3 vs. 1.70 cm3; p < 0.0001). Normalized T1-weighted intensity of DAWM-to-FWML was negatively associated with progression ( p < 0.00001).

Conclusion:

DAWM transformed into FWML over time, and this transformation was associated with clinical progression. DAWM-to-FWML voxels had greater normalized T1-weighted intensity decrease over time, in keeping with relatively greater tissue damage. Evaluation of DAWM in progressive multiple sclerosis provides a useful measure for therapies aiming to protect this at-risk tissue with the potential to slow progression.

Are multi-contrast magnetic resonance images necessary for segmenting multiple sclerosis brains? A large cohort study based on deep learning

BACKGROUND

Magnetic resonance images with multiple contrasts or sequences are commonly used for segmenting brain tissues, including lesions, in multiple sclerosis (MS). However, acquisition of images with multiple contrasts increases the scan time and complexity of the analysis, possibly introducing factors that could compromise segmentation quality.

OBJECTIVE

To investigate the effect of various combinations of multi-contrast images as input on the segmented volumes of gray (GM) and white matter (WM), cerebrospinal fluid (CSF), and lesions using a deep neural network.

METHODS

U-net, a fully convolutional neural network was used to automatically segment GM, WM, CSF, and lesions in 1000 MS patients. The input to the network consisted of 15 combinations of FLAIR, T1-, T2-, and proton density-weighted images. The Dice similarity coefficient (DSC) was evaluated to assess the segmentation performance. For lesions, true positive rate (TPR) and false positive rate (FPR) were also evaluated. In addition, the effect of lesion size on lesion segmentation was investigated.

RESULTS

Highest DSC was observed for all the tissue volumes, including lesions, when the input was combination of all four image contrasts. All other input combinations that included FLAIR also provided high DSC for all tissue classes. However, the quality of lesion segmentation showed strong dependence on the input images. The DSC and TPR values for inputs with the four contrast combination and FLAIR alone were very similar, but FLAIR showed a moderately higher FPR for lesion size <100 μl. For lesions smaller than 20 μl all image combinations resulted in poor performance. The segmentation quality improved with lesion size.

CONCLUSIONS

Best performance for segmented tissue volumes was obtained with all four image contrasts as the input, and comparable performance was attainable with FLAIR only as the input, albeit with a moderate increase in FPR for small lesions. This implies that acquisition of only FLAIR images provides satisfactory tissue segmentation. Lesion segmentation was poor for very small lesions and improved rapidly with lesion size.

Detecting neurodegenerative pathology in multiple sclerosis before irreversible brain tissue loss sets in

Background

Multiple sclerosis (MS) is a complex chronic inflammatory and degenerative disorder of the central nervous system. Accelerated brain volume loss, or also termed atrophy, is currently emerging as a popular imaging marker of neurodegeneration in affected patients, but, unfortunately, can only be reliably interpreted at the time when irreversible tissue damage likely has already occurred. Timing of treatment decisions based on brain atrophy may therefore be viewed as suboptimal.

Main body

This Narrative Review focuses on alternative techniques with the potential of detecting neurodegenerative events in the brain of subjects with MS prior to the atrophic stage. First, metabolic and molecular imaging provide the opportunity to identify early subcellular changes associated with energy dysfunction, which is an assumed core mechanism of axonal degeneration in MS. Second, cerebral hypoperfusion has been observed throughout the entire clinical spectrum of the disorder but it remains an open question whether this serves as an alternative marker of reduced metabolic activity, or exists as an independent contributing process, mediated by endothelin-1 hyperexpression. Third, both metabolic and perfusion alterations may lead to repercussions at the level of network performance and structural connectivity, respectively assessable by functional and diffusion tensor imaging. Fourth and finally, elevated body fluid levels of neurofilaments are gaining interest as a biochemical mirror of axonal damage in a wide range of neurological conditions, with early rises in patients with MS appearing to be predictive of future brain atrophy.

Conclusions

Recent findings from the fields of advanced neuroradiology and neurochemistry provide the promising prospect of demonstrating degenerative brain pathology in patients with MS before atrophy has installed. Although the overall level of evidence on the presented topic is still preliminary, this Review may pave the way for further longitudinal and multimodal studies exploring the relationships between the abovementioned measures, possibly leading to novel insights in early disease mechanisms and therapeutic intervention strategies.

Advances in brain imaging in multiple sclerosis

Brain imaging is increasingly used to support clinicians in diagnosing multiple sclerosis (MS) and monitoring its progression. However, the role of magnetic resonance imaging (MRI) in MS goes far beyond its clinical application. Indeed, advanced imaging techniques have helped to detect different components of MS pathogenesis in vivo, which is now considered a heterogeneous process characterized by widespread damage of the central nervous system, rather than multifocal demyelination of white matter. Recently, MRI biomarkers more sensitive to disease activity than clinical disability outcome measures, have been used to monitor response to anti-inflammatory agents in patients with relapsing-remitting MS. Similarly, MRI markers of neurodegeneration exhibit the potential as primary and secondary outcomes in clinical trials for progressive phenotypes. This review will summarize recent advances in brain neuroimaging in MS from the research setting to clinical applications.

Lifespan normative data on rates of brain volume changes

We provide here normative values of yearly percentage brain volume change (PBVC/y) as obtained with Structural Imaging Evaluation, using Normalization, of Atrophy, a widely used open-source software, developing a PBVC/y calculator for assessing the deviation from the expected PBVC/y in patients with neurological disorders. We assessed multicenter (34 centers, 11 acquisition protocols) magnetic resonance imaging data of 720 healthy participants covering the whole adult lifespan (16-90 years). Data of 421 participants with a follow-up > 6 months were used to obtain the normative values for PBVC/y and data of 392 participants with a follow-up <1 month were selected to assess the intrasubject variability of the brain volume measurement. A mixed model evaluated PBVC/y dependence on age, sex, and magnetic resonance imaging parameters (scan vendor and magnetic field strength). PBVC/y was associated with age (p < 0.001), with 60- to 70-year-old participants showing twice more volume decrease than participants aged 30-40 years. PBVC/y was also associated with magnetic field strength, with higher decreases when measured by 1.5T than 3T scanners (p < 0.001). The variability of PBVC/y normative percentiles was narrower as the interscan interval was longer (e.g., 80th normative percentile was 50% smaller for participants with 2-year than with 1-year follow-up). The use of these normative data, eased by the freely available calculator, might help in better discriminating pathological from physiological conditions in the clinical setting.

Aging and Brain Atrophy in Multiple Sclerosis

BACKGROUND AND PURPOSE

Brain atrophy accelerates at the age of 60 in healthy individuals (HI) and at disease onset in multiple sclerosis (MS) patients. Whether there is an exacerbating effect of aging superimposed on MS-related brain atrophy is unknown. We estimated the aging effect on lateral ventricular volume (LVV) and whole brain volume (WBV) changes in MS patients.

METHODS

1,982 MS patients (mean follow-up: 4.8 years) and 351 HI (mean follow-up: of 3.1 years), aged from 20 to 79 years old (yo), were collected retrospectively. Percent LVV change (PLVVC) and percent brain volume change (PBVC) on 1.5T and 3T MRI scanners (median of 3.9 scans per subject) were calculated. These were determined between all-time points and subjects were divided in six-decade age groups. MRI differences between age groups were calculated using analysis of covariance (ANCOVA).

RESULTS

Compared to HI, at first MRI, MS patients had significantly increased LVV in the age groups: 30-39 yo, 40-49 yo, 50-59 yo, 60-69 yo (all P < .0001), and 70-79 yo (P = .029), and decreased WBV in the age groups: 20-29 yo (P = .024), 30-39 yo (P = .031), 40-49 yo, and 50-59 yo (all P < .0001). Annualized PLVVC was significantly different between the age groups 20-59 and 60-79 yo in MS patients (P = .005) and HI (P < .0001), as was for PBVC in MS patients (P = .001), but not for HI (P = .521). There was a significant aging interaction effect in the annualized PLVVC (P = .001) between HI and MS patients, which was not observed for the annualized PBVC (P = .380).

CONCLUSIONS

Development of brain atrophy manifests progressively in MS patients, and occurs with a different pattern, as compared to aging HI. PLVVC increased across age in HI as compared to MS, while PBVC decreased across ages in both HI and MS.

Impairment of odor discrimination and identification is associated with disability progression and gray matter atrophy of the olfactory system in MS

BACKGROUND

Impairment of odor discrimination (D), identification (I), and threshold (T) are characteristic features of multiple sclerosis (MS).

OBJECTIVE

To identify patterns of gray matter concentration (GMC) associated with different qualities of olfactory function.

METHODS

Olfactory function (T and combined DI score) was measured by Sniffin' Sticks-Test over 2 years longitudinally, and T1-weighted 3-T magnetic resonance imaging (MRI) was performed in 37 MS patients and 18 matched healthy controls (HCs). Statistical parametric mapping (SPM) was applied to objectively identify changes of voxel-wise-GMC throughout the entire brain volume and to correlate image parameters with odor function.

RESULTS

SPM localized significant GMC decreases in the anterior cingulum as well as temporomesial and frontobasal brain areas of the MS group compared with HCs, and revealed significant correlations between lower DI scores and GMC decreases in the olfactory gyrus, anterior cingulum, temporal regions including the parahippocampus, and putamen. Contrarily, no correlations were found between T and GMC. Patients with disability progression had significantly lower mean temporomesial/putamen GMC (0.782 vs 0.804, p = 0.004) compared to patients without Expanded Disability Status Scale (EDSS) progression.

CONCLUSION

Impairment of DI, but not T is associated with GM atrophy in brain regions related to olfactory function. Further studies are warranted to investigate DI scores and temporomesial/putamen GMC as biomarkers for disability progression.

Brain regional volume estimations with NeuroQuant and FIRST: a study in patients with a clinically isolated syndrome

PURPOSE

Brain volume estimates from magnetic resonance images (MRIs) are of great interest in multiple sclerosis, and several automated tools have been developed for this purpose. The goal of this study was to assess the agreement between two tools, NeuroQuant® (NQ) and FMRIB's Integrated Registration Segmentation Tool (FIRST), for estimating overall and regional brain volume in a cohort of patients with a clinically isolated syndrome (CIS). In addition, white matter lesion volume was estimated with NQ and the Lesion Segmentation Toolbox (LST).

METHODS

One hundred fifteen CIS patients were analysed. Structural images were acquired on a 3.0-T system. The volume agreement between methods (by estimation of the intraclass correlation coefficient) was calculated for the right and left thalamus, caudate, putamen, pallidum, hippocampus, and amygdala, as well as for the total intracranial volume and white matter lesion volume.

RESULTS

In general, the estimated volumes were larger by NQ than FIRST, except for the pallidum. Agreement was low (ICC < 0.40) for the smaller structures (amygdala and pallidum) and fair to good (ICC > 0.40) for the remaining ones. Agreement was fair for lesion volume (ICC = 0.61), with NQ estimates lower than LST.

CONCLUSIONS

Agreement between NQ and FIRST brain volume estimates depends on the size of the structure of interest, with larger volumes achieving better agreement. In addition, concordance between the two tools does seem to be dependent on the presence of brain lesions.

Predicting clinical progression in multiple sclerosis after 6 and 12 years

BACKGROUND AND PURPOSE

To predict disability and cognition in multiple sclerosis (MS) after 6 and 12 years, using early clinical and imaging measures.

METHODS

A total of 115 patients with MS were selected and followed up after 2 and 6 years, with 79 patients also being followed up after 12 years. Disability was measured using the Expanded Disability Status Scale (EDSS); cognition was measured only at follow-up using neuropsychological testing. Predictors of interest included EDSS score, baseline brain and lesion volumes and their changes over 2 years, baseline age, clinical phenotype, sex and educational level.

RESULTS

Higher 6-year EDSS score was predicted by early EDSS score and whole-brain volume changes and baseline diagnosis of primary progressive MS (adjusted R²  = 0.56). Predictors for 12-year EDSS score included larger EDSS score changes and higher T1-hypointense lesion volumes (adjusted R²  = 0.38). Year 6 cognition was predicted by primary progressive MS phenotype, lower educational level, male sex and early whole-brain atrophy (adjusted R²  = 0.26); year 12 predictors included male sex, lower educational level and higher baseline T1-hypointense lesion volumes (adjusted R²  = 0.14).

CONCLUSIONS

Patients with early signs of neurodegeneration and a progressive disease onset were more prone to develop both disability progression and cognitive dysfunction. Male sex and lower educational level only affected cognitive dysfunction, which remains difficult to predict and probably needs more advanced imaging measures.

A GMCSF-Neuroantigen Tolerogenic Vaccine Elicits Systemic Lymphocytosis of CD4+ CD25high FOXP3+ Regulatory T Cells in Myelin-Specific TCR Transgenic Mice Contingent Upon Low-Efficiency T Cell Antigen Receptor Recognition

Previous studies showed that single-chain fusion proteins comprised of GM-CSF and major encephalitogenic peptides of myelin, when injected subcutaneously in saline, were potent tolerogenic vaccines that suppressed experimental autoimmune encephalomyelitis (EAE) in rats and mice. These tolerogenic vaccines exhibited dominant suppressive activity in inflammatory environments even when emulsified in Complete Freund's Adjuvant (CFA). The current study provides evidence that the mechanism of tolerance was dependent upon vaccine-induced regulatory CD25⁺ T cells (Tregs), because treatment of mice with the Treg-depleting anti-CD25 mAb PC61 reversed tolerance. To assess tolerogenic mechanisms, we focused on 2D2-FIG mice, which have a transgenic T cell repertoire that recognizes myelin oligodendrocyte glycoprotein peptide MOG35-55 as a low-affinity ligand and the neurofilament medium peptide NFM13-37 as a high-affinity ligand. Notably, a single subcutaneous vaccination of GMCSF-MOG in saline elicited a major population of FOXP3⁺ Tregs that appeared within 3 days, was sustained over several weeks, expressed canonical Treg markers, and was present systemically at high frequencies in the blood, spleen, and lymph nodes. Subcutaneous and intravenous injections of GMCSF-MOG were equally effective for induction of FOXP3⁺ Tregs. Repeated booster vaccinations with GMCSF-MOG elicited FOXP3 expression in over 40% of all circulating T cells. Covalent linkage of GM-CSF with MOG35-55 was required for Treg induction whereas vaccination with GM-CSF and MOG35-55 as separate molecules lacked Treg-inductive activity. GMCSF-MOG elicited high levels of Tregs even when administered in immunogenic adjuvants such as CFA or Alum. Conversely, incorporation of GM-CSF and MOG35-55 as separate molecules in CFA did not support Treg induction. The ability of the vaccine to induce Tregs was dependent upon the efficiency of T cell antigen recognition, because vaccination of 2D2-FIG or OTII-FIG mice with the high-affinity ligands GMCSF-NFM or GMCSF-OVA (Ovalbumin323-339), respectively, did not elicit Tregs. Comparison of 2D2-FIG and 2D2-FIG-Rag1 ^-/- strains revealed that GMCSF-MOG may predominantly drive Treg expansion because the kinetics of vaccine-induced Treg emergence was a function of pre-existing Treg levels. In conclusion, these findings indicate that the antigenic domain of the GMCSF-NAg tolerogenic vaccine is critical in setting the balance between regulatory and conventional T cell responses in both quiescent and inflammatory environments.

Brain Atrophy Is Associated with Disability Progression in Patients with MS followed in a Clinical Routine

BACKGROUND AND PURPOSE

The assessment of brain atrophy in a clinical routine is not performed routinely in multiple sclerosis. Our aim was to determine the feasibility of brain atrophy measurement and its association with disability progression in patients with MS followed in a clinical routine for 5 years.

MATERIALS AND METHODS

A total of 1815 subjects, 1514 with MS and 137 with clinically isolated syndrome and 164 healthy individuals, were collected retrospectively. Of 11,794 MR imaging brain scans included in the analysis, 8423 MRIs were performed on a 3T, and 3371 MRIs, on a 1.5T scanner. All patients underwent 3D T1WI and T2-FLAIR examinations at all time points of the study. Whole-brain volume changes were measured by percentage brain volume change/normalized brain volume change using SIENA/SIENAX on 3D T1WI and percentage lateral ventricle volume change using NeuroSTREAM on T2-FLAIR.

RESULTS

Percentage brain volume change failed in 36.7% of the subjects; percentage normalized brain volume change, in 19.2%; and percentage lateral ventricle volume change, in 3.3% because of protocol changes, poor scan quality, artifacts, and anatomic variations. Annualized brain volume changes were significantly different between those with MS and healthy individuals for percentage brain volume change (P < .001), percentage normalized brain volume change (P = .002), and percentage lateral ventricle volume change (P = .01). In patients with MS, mixed-effects model analysis showed that disability progression was associated with a 21.9% annualized decrease in percentage brain volume change (P < .001) and normalized brain volume (P = .002) and a 33% increase in lateral ventricle volume (P = .004).

CONCLUSIONS

All brain volume measures differentiated MS and healthy individuals and were associated with disability progression, but the lateral ventricle volume assessment was the most feasible.

Whole brain and deep gray matter atrophy detection over 5 years with 3T MRI in multiple sclerosis using a variety of automated segmentation pipelines

Background

Cerebral atrophy is common in multiple sclerosis (MS) and selectively involves gray matter (GM). Several fully automated methods are available to measure whole brain and regional deep GM (DGM) atrophy from MRI.

Objective

To assess the sensitivity of fully automated MRI segmentation pipelines in detecting brain atrophy in patients with relapsing-remitting (RR) MS and normal controls (NC) over five years.

Methods

Consistent 3D T1-weighted sequences were performed on a 3T GE unit in 16 mildly disabled patients with RRMS and 16 age-matched NC at baseline and five years. All patients received disease-modifying immunotherapy on-study. Images were applied to two pipelines to assess whole brain atrophy [brain parenchymal fraction (BPF) from SPM12; percentage brain volume change (PBVC) from SIENA] and two other pipelines (FSL-FIRST; FreeSurfer) to assess DGM atrophy (thalamus, caudate, globus pallidus, putamen). MRI change was compared by two sample t-tests. Expanded Disability Status Scale (EDSS) and timed 25-foot walk (T25FW) change was compared by repeated measures proportional odds models.

Results

Using FreeSurfer, the MS group had a ~10-fold acceleration in on-study volume loss than NC in the caudate (mean decrease 0.51 vs. 0.05 ml, p = 0.022). In contrast, caudate atrophy was not detected by FSL-FIRST (mean decrease 0.21 vs. 0.12 ml, p = 0.53). None of the other pipelines showed any difference in volume loss between groups, for whole brain or regional DGM atrophy (all p>0.38). The MS group showed on-study stability on EDSS (p = 0.47) but slight worsening of T25FW (p = 0.054).

Conclusions

In this real-world cohort of mildly disabled treated patients with RRMS, we identified ongoing atrophy of the caudate nucleus over five years, despite the lack of any significant whole brain atrophy, compared to healthy controls. The detectability of caudate atrophy was dependent on the MRI segmentation pipeline employed. These findings underscore the increased sensitivity gained when assessing DGM atrophy in monitoring MS.

MRI Markers and Functional Performance in Patients With CIS and MS: A Cross-Sectional Study

Introduction: Brain atrophy is a widely accepted marker of disease severity with association to clinical disability in multiple sclerosis (MS). It is unclear to which extent this association reflects common age effects on both atrophy and function. Objective: To explore how functional performance in gait, upper extremities and cognition is associated with brain atrophy in patients with Clinically Isolated Syndrome (CIS) and relapsing-remitting MS (RRMS), controlling for effects of age and sex. Methods: In 27 patients with CIS, 59 with RRMS (EDSS ≤3) and 63 healthy controls (HC), 3T MRI were analyzed for T2 lesion count (T2C), volume (T2V) and brain volumes [normalized brain volume (NBV), gray matter volume (NGMV), white matter volume (NWMV), thalamic volume (NThalV)]. Functional performance was measured with short maximum walking speed (SMSW speed), 9-hole peg test (9HPT) and symbol digit modalities test (SDMT). Linear regression models were created for functional variables with stepwise inclusion of age, sex and MR imaging markers. Results: CIS differed from HC only in T2C and T2V. RRMS differed from HC in NBV, NGMV and NThalV, T2C and T2V, but not in NWMV. A strong association with age was seen in HC, CIS and RRMS groups for NBV (r = -0.5 to -0.6) and NGMV (r = -0.6 to -0.8). Associations with age were seen in HC and RRMS but not CIS for NThalV (r = -0.3; r = -0.5), T2C (rs = 0.3; rs = 0.2) and T2V (rs = 0.3; rs = 0.3). No effect of age was seen on NWMV. Correlations of functional performance with age in RRMS were seen for SMSW speed, 9HPTand SDMT (r = -0.27 to -0.46). Regression analyses yielded significant models only in the RRMS group for 9HPT, SMSW speed and EDSS. These included NBV, NGMV, NThalV, NWMV, logT2V, age and sex as predictors. NThalV was the only MRI variable predicting a functional measure (9HPTr) with a higher standardized beta than age and sex (R2 = 0.36, p < 1e-04). Conclusion: Thalamic atrophy was a stronger predictor of hand function (9HPT) in RRMS, than age and sex. This underlines the clinical relevance of thalamic atrophy and the relevance of hand function as a clinical marker even in mildly disabled patients.

Neurofilament levels, disease activity and brain volume during follow-up in multiple sclerosis

Background

There is a need for clinically useful biomarkers of disease activity in clinically isolated syndrome (CIS) and relapsing remitting MS (RRMS). The aim of this study was to assess the correlation between neurofilament light chain (NFL) in cerebrospinal fluid (CSF) and serum and the relationship between NFL and other biomarkers, subsequent disease activity, and brain volume loss in CIS and RRMS.

Methods

A panel of neurodegenerative and neuroinflammatory markers were analyzed in repeated CSF samples from 41 patients with CIS or RRMS in a prospective longitudinal cohort study and from 22 healthy controls. NFL in serum was analyzed using a single-molecule array (Simoa) method. “No evidence of disease activity-3” (NEDA-3) status and brain volume (brain parenchymal fraction calculated using SyMRI®) were recorded during 4 years of follow-up.

Results

NFL levels in CSF and serum correlated significantly (all samples, n = 63, r 0.74, p < 0.001), but CSF-NFL showed an overall stronger association profile with NEDA-3 status, new T2 lesions, and brain volume loss. CSF-NFL was associated with both new T2 lesions and brain volume loss during follow-up, whereas CSF-CHI3L1 was associated mainly with brain volume loss and CXCL1, CXCL10, CXCL13, CCL22, and MMP-9 were associated mainly with new T2 lesions.

Conclusions

Serum and CSF levels of NFL correlate, but CSF-NFL predicts and reflects disease activity better than S-NFL. CSF-NFL levels are associated with both new T2 lesions and brain volume loss. Our findings further add to the accumulating evidence that CSF-NFL is a clinically useful biomarker in CIS and RRMS and should be considered in the expanding NEDA concept. CSF-CXCL10 and CSF-CSF-CHI3L1 are potential markers of disease activity and brain volume loss, respectively.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1249-7) contains supplementary material, which is available to authorized users.