Correlation between the clinical disability and T1 hypointense lesions' volume in cerebral magnetic resonance imaging of multiple sclerosis patients: A systematic review and meta-analysis

BACKGROUND

To evaluate the correlation between T1 hypointense lesions' mean volume on cerebral MRI with disability level of patients with multiple sclerosis.

METHODS

We included studies testing the desired outcome in adult patients diagnosed with RRMS or SPMS. In Feb 2021, we searched PubMed, Embase, CENTRAL, and Web of Science to find relevant studies. All included studies were assessed for the risk of bias using a tailored version of the Quality in Prognosis Studies (QUIPS) tool. Extracted correlation coefficients were converted to the Fisher's z scale, and a meta-analysis using a random-effects model was performed on the results.

RESULTS

We included 27 studies (1919 participants). Meta-analysis revealed a correlation coefficient of 0.32 (95% CI 0.26-0.37) between T1 hypointense lesions' mean volume and EDSS score.

DISCUSSION

The correlation between T1 hypointense lesions' mean volume and EDSS was interpreted as low to slightly moderate. The certainty of the evidence was judged to be high.

Modelling and sample size reestimation for longitudinal count data with incomplete follow up

We consider modelling and inference as well as sample size estimation and reestimation for clinical trials with longitudinal count data as outcomes. Our approach is general but is rooted in design and analysis of multiple sclerosis trials where lesion counts obtained by magnetic resonance imaging are important endpoints. We adopt a binomial thinning model that allows for correlated counts with marginal Poisson or negative binomial distributions. Methods for sample size planning and blinded sample size reestimation for randomised controlled clinical trials with such outcomes are developed. The models and approaches are applicable to data with incomplete observations. A simulation study is conducted to assess the effectiveness of sample size estimation and blinded sample size reestimation methods. Sample sizes attained through these procedures are shown to maintain the desired study power without inflating the type I error. Data from a recent trial in patients with secondary progressive multiple sclerosis illustrate the modelling approach.

Normal-appearing grey and white matter T1 abnormality in early relapsing–remitting multiple sclerosis: a longitudinal study

Objective

To investigate the presence and evolution of T1 relaxation time abnormalities in normal-appearing white matter (NAWM) and grey matter (GM), early in the course of relapsing–remitting multiple sclerosis (MS).

Methods

Twenty-three patients with early relapsing–remitting MS and 14 healthy controls were imaged six monthly for up to three years. Mean follow-up was 26 months for MS patients and 24 months for controls. Dual-echo fast-spin echo and gradient-echo proton-density and T1-weighted data sets (permitting the calculation of a T1 map) were acquired in all subjects. GM and NAWM T1 histograms were produced and a hierarchical regression model was used to investigate changes in T1 over time.

Results

At baseline, significant patient-control differences were seen, both in NAWM (P = 0.001) and in GM (P = 0.01). At follow-up, there was no evidence for a serial change in either mean T1 or peak-location for either NAWM or GM. There was weak evidence for a decline in patient NAWM peak-height and also evidence for a decline in control GM peak-height.

Conclusion

There are significant and persistent abnormalities of NAWM and GM T1 in early relapsing-remitting MS. Further studies should address whether such T1 measures have a role in prognosis or therapeutic monitoring. Multiple Sclerosis 2007; 13:169–177. http://msj.sagepub.com

Beta-interferon exposure and onset of secondary progressive multiple sclerosis

BACKGROUND AND PURPOSE

Beta-interferons (IFNβ) are the most widely prescribed drugs for patients with multiple sclerosis (MS). However, whether or not treatment with IFNβ can delay secondary progressive MS (SPMS) onset remains unknown. Our aim was to examine the association between IFNβ exposure and SPMS onset in patients with relapsing-remitting MS (RRMS).

METHODS

A retrospective cohort study using British Columbia (Canada) population-based clinical and health administrative data (1985-2008) was conducted. RRMS patients treated with IFNβ (n = 794) were compared with untreated contemporary (n = 933) and historical (n = 837) controls. Cohort entry was the first clinic visit during which patients became eligible for IFNβ treatment (baseline). The outcome was time from baseline to SPMS onset. Cox regression models with IFNβ as a time-dependent exposure were adjusted for sex, and baseline age, disease duration, disability, *socioeconomic status and *comorbidities (*available for the contemporary cohorts only). Additional analyses included propensity score adjustment.

RESULTS

The median follow-up for the IFNβ-treated, untreated contemporary and historical controls were 5.7, 3.7 and 7.3 years, and the proportions of patients reaching SPMS were 9.2%, 11.8% and 32.9%, respectively. After adjustment for confounders, IFNβ exposure was not associated with the risk of reaching SPMS when either the contemporary or the historical untreated cohorts were considered (hazard ratio 1.07; 95% confidence interval 0.93-1.48, and hazard ratio 1.04; 95% confidence interval 0.74-1.46, respectively). Further adjustments and the propensity score yielded results consistent with the main analysis.

CONCLUSIONS

Amongst patients with RRMS, use of IFNβ was not associated with a delayed onset of SPMS.

Clinical and imaging metrics for monitoring disease progression in patients with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the CNS leading to clinical disability in 250,000-350,000 young adults in the USA and Europe. The disease affects both white matter (WM) and gray matter (GM) tissues of the brain and spinal cord. While WM disease is easily quantified using currently available magnetic resonance imaging (MRI) techniques, identification and quantification of GM disease present a daily challenge. Nonconventional brain and spinal cord MRI techniques, including magnetization transfer, MRI spectroscopy and diffusion tensor imaging, have improved our understanding of MS pathology in the deep GM. The sensitivity of high-resolution MRI obtained at a high magnetic field will improve the detection of spinal cord and brain cortical GM disease. The appropriate use of the above-mentioned techniques has the potential to more accurately explain the level of disability in MS patients.

Diagnostic biomarkers in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the CNS and comprises a heterogeneous spectrum of disease subtypes. The distinctive variability of clinical presentations, histopathologic and immunologic patterns, as well as neuroradiologic phenotypes in MS poses a diagnostic challenge to the attending physician and claims a more differentiated typing of MS patients by diagnostic biomarkers in order to anticipate the expected disease course and to stratify patients for specifically tailored therapies. In this paper, the major biomarkers presently recommended in the diagnosis of MS are reviewed, including magnetic resonance imaging, the analysis of cerebrospinal fluid parameters and the diagnostic relevance of antibodies to aquaporin-4 water channels and myelin antigens.

Intramuscular interferon beta-1a is effective in Japanese patients with relapsing-remitting multiple sclerosis: a pre-treatment versus treatment comparison study of gadolinium-enhanced MRI brain lesions

BACKGROUND AND OBJECTIVE

Interferon beta (IFNβ) is standard therapy for multiple sclerosis (MS). The efficacy of intramuscular (IM) IFNβ-1a (AVONEX(®)) was assessed in 25 Japanese patients with relapsing-remitting MS (RRMS).

METHODS

Patients with RRMS not previously treated with IFNβ or other disease-modifying therapies were included in this 36-week study. The primary outcome was the average total number of gadolinium-enhanced lesions detected on four brain MRI scans during the last 12 weeks of 24 weeks' treatment with IM IFNβ-1a 30 μg once weekly compared with the number during the 12-week pre-treatment period. Lesions were counted by blinded investigators.

RESULTS

IM IFNβ-1a significantly decreased the median number of gadolinium-enhanced lesions from 2.5 to 0.3 (p < 0.0001) compared with pre-treatment values. The median number of new gadolinium-enhanced lesions also decreased significantly from 2.0 to 0.3 (p = 0.0002). Serum neopterin was induced in a manner similar to that observed previously in a Caucasian RRMS population. No new adverse events occurred during the study.

CONCLUSION

This first study of IM IFNβ-1a in Japanese patients with RRMS demonstrated a level of efficacy similar to that reported in Caucasian patients based on an assessment of pre-treatment and post-treatment gadolinium-enhanced lesions.

Multiple sclerosis normal-appearing white matter: pathology-imaging correlations

OBJECTIVE

The study was undertaken to determine the pathologic basis of subtle abnormalities in magnetization transfer ratio (MTR) and diffusion tensor imaging (DTI) parameters observed in normal-appearing white matter (NAWM) in multiple sclerosis brains.

METHODS

Brain tissues were obtained through a rapid postmortem protocol that included in situ magnetic resonance imaging (MRI). Four types of MRI-defined regions of interest (ROIs) were analyzed: (1) regions that were abnormal on all images (T2T1MTR lesions); (2) NAWM regions with slightly abnormal MTR located close to white matter lesions (sa-WM Close); (3) NAWM regions with slightly abnormal MTR located far from lesions (sa-WM Far); and (4) NAWM regions with normal MTR (NAWM). Immunohistochemical analysis for each ROI comprised immunostaining for myelin, axonal markers, activated microglia/macrophages, astrocytes, plasma proteins, and blood vessels.

RESULTS

Forty-eight ROIs from 4 secondary progressive MS brains were analyzed. sa-WM Close ROIs were associated with significantly more axonal swellings. There were more enlarged major histocompatibility complex II(+) microglia and macrophages detected in sa-WM Far, sa-WM Close, and T2T1MTR lesions than in NAWM. Across all ROIs, MTR and DTI measures were moderately correlated with myelin density, axonal area, and axonal counts. Excluding T2T1MTR lesions from analysis revealed that MTR and DTI measures in nonlesional white matter (WM) were correlated with activated microglia, but not with axonal or myelin integrity.

INTERPRETATION

The pathologic substrates for MRI abnormalities in NAWM vary based on distance from focal WM lesions. Close to WM lesions, axonal pathology and microglial activation may explain subtle MRI changes. Distant from lesions, microglial activation associated with proximity to cortical lesions might underlie MRI abnormalities.

A functional magnetic resonance proof of concept pilot trial of cognitive rehabilitation in multiple sclerosis

BACKGROUND

Cognitive impairment is frequent in multiple sclerosis (MS) and lacks effective treatment. Cognitive rehabilitation is widely applied in neurorehabilitation settings. Functional magnetic resonance imaging (fMRI) may help in investigating changes in brain activity and provide a tool to assess the efficacy of rehabilitation.

AIM

To investigate the effect on brain activity as measured by fMRI of a cognitive rehabilitation programme in patients with MS and cognitive impairment.

METHOD

Fifteen patients with MS and cognitive impairment and five healthy subjects were recruited. Neuropsychological assessments were performed in patients with MS at study entry and after rehabilitation to assess cognitive changes. fMRI scans were performed at week -5 (baseline), week 0 (immediately before rehabilitation) and week 5 (immediately after rehabilitation). The fMRI paradigm was the Paced Auditory Serial Addition Test (PASAT). The cognitive rehabilitation programme was composed of 15 computer-aided drill and practice sessions and five non-computer-aided cognitive stimulation group sessions (over 5 weeks). Strict guidelines ensured comparability of all rehabilitation interventions.

RESULTS

Patients had increased brain fMRI activity after rehabilitation in several cerebellar areas when compared with healthy subjects. After rehabilitation, patients had significantly improved their performance on the backward version of the Digit Span Test (p = 0.007) and on a composite score of neuropsychological outcomes (p = 0.009).

CONCLUSION

The results of the present study indicate that this cognitive rehabilitation programme increases brain activity in the cerebellum of cognitively impaired patients with MS. The role of fMRI in the assessment of neurorehabilitation schemes warrants further investigation.

Examination of the role of MRI in multiple sclerosis: a problem orientated approach

Current multiple sclerosis (MS) is generally thought to consist of two general pathological processes; acute inflammation and degeneration. The relationship between these two components is not understood. What is clear, however, is that the measures of acute inflammation are a poor predictor of long-term disability. Although some have suggested that inflammation may not contribute directly to the essential pathology in MS or that it is secondary to tissue degeneration, most students of the disease believe that the two processes are linked. Therefore, applications of MRI to measure both components of the disease are important. As most readers know, considerable success has been achieved in measuring acute inflammation and very little success has been obtained in identifying measures that correlate with disability and the prediction of future disability has not been achieved. In this review, we will examine the successes and failures of MRI in measuring these two components of the disease process. Consequently, we will not attempt to provide a detailed review of each MRI technique or sequence that has been applied to MS (a number of excellent reviews are available) but rather discuss how these techniques have been applied to answer specific questions. We will provide some comments on the use of MRI in clinical trials as well as in clinical practice. Finally, we will end with a brief discussion of future challenges.

Evaluation of multiple sclerosis diagnostic criteria in Suzhou, China--risk of under-diagnosis in a low prevalence area

OBJECTIVE

To evaluate the discharge diagnosis of demyelinating diseases in the central nervous system (CNS) and analyze the predictive value of the new diagnostic criteria in Suzhou, China.

MATERIALS AND METHODS

We collected clinical information and data of laboratory examinations for all cases with a diagnosis of various demyelinating diseases in the CNS. All data were reviewed individually by four senior neurologists, and a diagnosis was finally given to each patient according to the McDonald criteria and the Poser criteria for multiple sclerosis (MS).

RESULTS

In the analysis, 176 patients with a diagnosis of demyelinating diseases in the CNS at discharge were included. In 82 patients with a diagnosis of MS at discharge, the MS diagnosis was confirmed for 74 patients according to the McDonald criteria for MS, and the positive predictive value for the discharge diagnosis of MS was 90.2% (74/82). According to the Poser criteria, 61 patients were diagnosed as MS. The consistency of the two diagnostic criteria for MS was 78.4%, based on the results of the evaluation.

CONCLUSIONS

Under-diagnosis of MS could be one of the explanations for the low prevalence of MS in China. Compared to the Poser criteria, the McDonald criteria had a higher sensitivity for the diagnosis of MS.

Multiple sclerosis lesions: insights from imaging techniques

The hallmark of multiple sclerosis (MS) pathology is the presence of inflammatory demyelinated lesions distributed throughout the CNS. Along with more diffuse tissue abnormalities, it is considered one of the major determinants of neurological deficit in MS. Conventional MRI has contributed to improve our understanding of MS pathology and has provided objective and reliable measures to monitor the effect of treatments. Advanced MRI techniques have offered the opportunity to quantify pathological changes in lesions, as well as in normal-appearing brain tissue and to characterize their dynamics. This review will discuss the characteristics and development of MS lesions and the contribution of conventional and quantitative MRI techniques to understanding pathological changes associated with them.

Neutralizing antibodies to interferon-beta and other immunological treatments for multiple sclerosis: prevalence and impact on outcomes

Biopharmaceuticals can induce antibodies, which interact with and neutralize the therapeutic effect of such drugs and are therefore termed neutralizing antibodies (NAbs). In the treatment of multiple sclerosis, NAbs against interferon (IFN)-beta and natalizumab have been recognized. The prevalence of NAbs against different IFNbeta preparations varies widely, mainly depending on the product but also on other factors such as amino acid sequence variations, glycosylation, formulation, route and frequency of application, dose, duration of treatment and patient characteristics (human leukocyte antigen [HLA] status). IFNbeta-1a given intramuscularly induces significantly less NAbs than any other IFNbeta formulation. The longitudinal development of NAbs also differs between IFNbeta preparations, with higher reversion rates in IFNbeta-1b-treated compared with IFNbeta-1a-treated patients. The negative effect of NAbs on various outcome measures is very consistent across many studies, specifically when observation periods are longer than 2 years. NAbs against natalizumab occur less frequently (6%) and, like NAbs against IFNbeta, they are associated with a loss of clinical and radiological efficacy of the drug.

One-year MRI scan predicts clinical response to interferon beta in multiple sclerosis

BACKGROUND AND PURPOSE

To define the predictive value of clinical and magnetic resonance imaging (MRI) characteristics in identifying relapsing-remitting multiple sclerosis (RR-MS) patients with sustained disability progression during interferon beta (IFNB) treatment.

METHODS

All patients receiving treatment with one of the available IFNB formulations for at least 1 year were included in this single-centre, prospective and post-marketing study. Demographic, clinical and MRI data were collected at IFNB start and at 1 year of therapy; patients were followed-up at least yearly. Poor clinical response was defined as the occurrence of a sustained disability progression of > or =1 point in the Expanded Disability Status Scale (EDSS) during the follow-up period.

RESULTS

Out of 454 RR-MS patients starting IFNB therapy, data coming from 394 patients with a mean follow-up of 4.8 (2.4) years were analysed. Sixty patients were excluded because of too short follow-up. Less than 1/3 (30.4%) of the patients satisfied the criterion of 'poor responders'. Patients presenting new lesions on T2-weighted MRI scan after 1 year of therapy (compared with baseline) had a higher risk of being poor responder to treatment with IFNB during the follow-up period (HR 16.8, 95% CI 7.6-37.1, P < 0.001). An augmented risk increasing the number of lesions was observed, with a 10-fold increase for each new lesion.

CONCLUSIONS

Developing new T2-hyperintense lesions during IFNB treatment was the best predictor of long-term poor response to therapy. MRI scans performed after 1 year of IFNB treatment may be useful in contributing to early identification of poor responders.

Distinct spatiotemporal pattern of CNS lesions revealed by USPIO-enhanced MRI in MOG-induced EAE rats implicates the involvement of spino-olivocerebellar pathways

USPIO-enhanced MRI allows non-invasive visualization of mononuclear cell infiltration into CNS lesions in MS and EAE. Herein, we show a distinct spatiotemporal pattern of CNS lesions that reveals the involvement of spino-olivocerebellar pathways in MOG-induced EAE rats using USPIO-enhanced MRI. Specifically, lesions of the inferior olives were observed primarily in the acute phase whereas lesions of cerebellum or spinal cord/brainstem were observed during the relapse phase. Further, behavioral deficits observed from these animals are consistent with the functional role of spino-olivocerebellar pathways in coordination and movement. Collectively, our results provide new insights into the pathophysiology of this animal model of MS.

Quantitative electroencephalography reveals different physiological profiles between benign and remitting-relapsing multiple sclerosis patients

BACKGROUND

A possible method of finding physiological markers of multiple sclerosis (MS) is the application of EEG quantification (QEEG) of brain activity when the subject is stressed by the demands of a cognitive task. In particular, modulations of the spectral content that take place in the EEG of patients with multiple sclerosis remitting-relapsing (RRMS) and benign multiple sclerosis (BMS) during a visuo-spatial task need to be observed.

METHODS

The sample consisted of 19 patients with RRMS, 10 with BMS, and 21 control subjects. All patients were free of medication and had not relapsed within the last month. The power spectral density (PSD) of different EEG bands was calculated by Fast-Fourier-Transformation (FFT), those analysed being delta, theta, alpha, beta and gamma. Z-transformation was performed to observe individual profiles in each experimental group for spectral modulations. Lastly, correlation analyses was performed between QEEG values and other variables from participants in the study (age, EDSS, years of evolution and cognitive performance).

RESULTS

Nearly half (42%) the RRMS patients showed a statistically significant increase of two or more standard deviations (SD) compared to the control mean value for the beta-2 and gamma bands (F = 2.074, p = 0.004). These alterations were localized to the anterior regions of the right hemisphere, and bilaterally to the posterior areas of the scalp. None of the BMS patients or control subjects had values outside the range of +/- 2 SD. There were no significant correlations between these values and the other variables analysed (age, EDSS, years of evolution or behavioural performance).

CONCLUSION

During the attentional processing, changes in the high EEG spectrum (beta-2 and gamma) in MS patients exhibit physiological alterations that are not normally detected by spontaneous EEG analysis. The different spectral pattern between pathological and controls groups could represent specific changes for the RRMS patients, indicative of compensatory mechanisms or cortical excitatory states representative of some phases during the RRMS course that are not present in the BMS group.

Identification and treatment of symptoms associated with inflammation in medically ill patients

Medically ill patients present with a high prevalence of non-specific comorbid symptoms including pain, sleep disorders, fatigue and cognitive and mood alterations that is a leading cause of disability. However, despite major advances in the understanding of the immune-to-brain communication pathways that underlie the pathophysiology of these symptoms in inflammatory conditions, little has been done to translate this newly acquired knowledge to the clinics and to identify appropriate therapies. In a multidisciplinary effort to address this problem, clinicians and basic scientists with expertise in areas of inflammation, psychiatry, neurosciences and psychoneuroimmunology were brought together in a specialized meeting organized in Bordeaux, France, on May 28-29, 2007. These experts considered key questions in the field, in particular those related to identification and quantification of the predominant symptoms associated with inflammation, definition of systemic and central markers of inflammation, possible domains of intervention for controlling inflammation-associated symptoms, and relevance of animal models of inflammation-associated symptoms. This resulted in a number of recommendations that should improve the recognition and management of inflammation-associated symptoms in medically ill patients.

Retinal nerve fiber layer thickness is associated with brain MRI outcomes in multiple sclerosis

Multiple sclerosis is characterized by the dual pathological processes of inflammation and neurodegeneration. Conventional MRI techniques are considered the best tools for assessing and monitoring lesion burden and inflammation but are limited in their ability to assess axonal loss. Optical coherence tomography (OCT) is a simple high-resolution technique that uses near infrared light to quantify the thickness of the retinal nerve fiber layer (RNFL), which contains only non-myelinated axons. RNFL thickness (RNFLT) was measured using OCT on thirty consecutive MS patients (60 eyes). Eighteen patients underwent quantitative MRI analysis including T1- and T2-lesion volumes (LV), normalized brain volume (NBV), normalized cortical, white and gray matter volumes (NCV, NWMV, and NGMV), and mean whole brain diffusivity (MD). There was a strong association between NBV and average RNFL thickness (p<0.001, partial rp=0.77). The T2-LV and NWMV were significantly associated with average RNFL thickness (p=0.002, partial rp= -0.76 and p=0.005, partial rp=0.68, respectively) and there were trends toward association with T1-LV (p=0.041) and NGMV (p=0.067). There was negative correlation between average RNFL thickness (average of both eyes) and disability as assessed by EDSS (p=0.02). The results support potential usefulness of OCT for MS patient monitoring and research applications.

Imaging correlates of axonal swelling in chronic multiple sclerosis brains

OBJECTIVE

T2-weighted magnetic resonance imaging is a sensitive tool for monitoring progression of multiple sclerosis, but it does not provide information on the severity of the underlying tissue damage. Measurement of T1 hypointensities and magnetization transfer ratio (MTR) can potentially distinguish lesions with more severe tissue damage. The objective of this study was to use image-guided pathology to determine histological differences between lesions that are abnormal only on T2-weighted images versus lesions that are abnormal on T2-weighted, T1-weighted, and MTR images.

METHODS

A total of 110 regions were selected from postmortem magnetic resonance images of 10 multiple sclerosis patients. Regions were classified into three magnetic resonance imaging-defined categories: normal-appearing white matter; abnormal on T2-weighted image only (T2-only); and abnormal on T2-weighted, T1-weighted, and MTR images (T2T1MTR). Myelin status, lesion activity, astrocytosis, serum protein distribution, axonal area, and axonal loss were evaluated histopathologically.

RESULTS

Comparisons between groups showed that T2T1MTR regions were more likely to be demyelinated (83% compared with 55% of T2-only regions) and more likely to be chronic inactive lesions (68% compared with 0% of demyelinated T2-only regions). There was no difference between T2-only and T2T1MTR regions in axonal area, but there was a significant difference in axonal count, indicating that axons in the T2T1MTR regions were enlarged relative to those in T2-only regions.

INTERPRETATION

Axonal swelling and axonal loss were major pathological features that distinguish T2T1MTR regions from T2-only regions.

Magnetic resonance imaging as a surrogate outcome measure of disability in multiple sclerosis: Have we been overly harsh in our assessment?

OBJECTIVE

The validity of magnetic resonance imaging (MRI) as a surrogate outcome measure in multiple sclerosis (MS) clinical trials has been greeted skeptically both by the US Food and Drug Administration and by clinical researchers because the correlation between current MRI measures and clinical disability, although significant, has generally been low. Thus, the reported correlations have varied between rho = 0.09 and rho = 0.60, and have often been at the lower end of this range. Nevertheless, it still appears possible that this apparently poor correlation is due not to any deficiency either with our current MRI measures or with our disability scale, but rather to the intrinsic variability in the clinical expression of MS plaques in different anatomical locations.

METHODS

This article explores this possibility through the development of a general mathematical model for the relation between MRI changes and clinical disability in patients with MS.

RESULTS

Under the conditions of this general model, the maximum expected correlation between clinical disability and MRI will typically be quite low (eg, rho = 0.2-0.3), even when it is assumed that the MRI changes are the sole determinant of disability and, furthermore, that the scale used to measure disability is ideal.

INTERPRETATION

These observations, together with the significant relations already reported between MRI and disability (with observed correlations in the range of 0.2-0.6), actually suggest that our available clinical and MRI measures are considerably better than is currently believed and, in fact, that the MRI may be a valid surrogate marker in the assessment of treatment efficacy in MS.

Multiple sclerosis patients show a highly significant decrease in alpha band interhemispheric synchronization measured using MEG

MEG data were acquired from a group of relapsing-remitting multiple sclerosis (MS) patients and a group of healthy controls, using an eyes-closed no-task condition. An interhemispheric coherence measure (IHCM), reflecting the synchronization between the left and right hemispheres, showed a decrease in the patients, particularly in the alpha band. No comparable differences were seen in the alpha band power or its distribution over the head. The observed difference is in agreement with a reduced long-range connectivity in the brains of MS patients. The IHCM was found to be reproducible in controls over a period of more than 15 months. Further studies should investigate whether MEG derived synchronization measures may be useful as markers for MS disease load.

Using imaging biomarkers to accelerate drug development and clinical trials

There is increasing evidence that human medical imaging can help answer key questions that arise during the drug development process. Imaging modalities such as magnetic resonance imaging, computed tomography and positron emission tomography can offer significant insights into the bioactivity, pharmacokinetics and dosing of drugs, in addition to supporting registration applications. In this review, examples from oncology, neurology, psychiatry, infectious diseases and inflammatory diseases are used to illustrate the role imaging can play. We conclude with some remarks concerning new developments that will be required to significantly advance the field of pharmaco-imaging.

Intérêt du recalage automatique des IRM cérébrales dans le suivi des scléroses en plaques

INTRODUCTION

Magnetic resonance imaging (MRI) has transformed management of patients with multiple sclerosis. The exact contribution of brain MRI remains a subject of debate, but it is generally considered to provide a more specific and more sensitive outcome measure for monitoring purposes and for testing new therapies. The choice of MRI techniques, and measurement reproducibility for multiple sclerosis brain lesions are not defined with precision for routine practice. There are many sources of error when comparing successive images which can be overcome to some extent with repositioning and image processing techniques.

METHODS

We evaluated the impact of image repositioning on treatment decision-making for twelve relapsing remitting patients. Brain MRIs were performed every three months for a one-year period. Two neurologists interpreted the non-repositioned and repositioned images giving their analysis of changes in the lesions visualized on the T2 sequences and their therapeutic decisions.

RESULTS

For the first neurologist, analysis of the non-repositioned images yielded six patients whose lesions had worsened while for the repositioned images there were only three. For the second neurologist, four patients had more lesions with the non-repositioned images and only three with repositioning. The subjective interpretations were the same for the two neurologists when they used repositioned images.

CONCLUSIONS

Comparison by two neurologists of non-repositioned and repositioned MRI, with no other image processing, affected the analysis and in certain cases propositions for treatment.

Biomarkers and surrogate outcomes in neurodegenerative disease: lessons from multiple sclerosis

Multiple sclerosis (MS) is a chronic disease of the CNS that most commonly affects young adults. It is usually characterized in the early years by acute relapses followed by partial or complete remission; in later years progressive and irreversible disability develops. Because of the protracted and unpredictable clinical course, biological surrogate markers are much needed to make clinical trials of potential disease-modifying treatments more efficient. Magnetic resonance (MR) outcome measures are now widely used to monitor treatment outcome in MS trials. Areas of multifocal inflammation are detected with a high sensitivity as new areas of gadolinium enhancement and T2 abnormality, and these may be considered as surrogate markers for clinical relapses. However, progressive disability is not clearly related to inflammatory lesions but rather to a progressive and diffuse process with increasing neuroaxonal loss. MR surrogate measures for neuroaxonal loss include atrophy (tissue loss in brain and spinal cord), N-acetyl aspartate, and T1 hypointense lesions. Diffuse abnormality in normal appearing brain tissue may also be monitored using magnetization transfer ratio and other quantitative MR measures. For treatment trials of new agents aimed at preventing disability, measures of neuroaxonal damage should be acquired, especially atrophy, which occurs at all stages of MS and which can be quantified in a sensitive and reproducible manner. Because the MR surrogates for neuroaxonal loss are not yet validated as predicting future disability, definitive trials should continue to monitor an appropriate disability endpoint.

Disease-modifying therapies in multiple sclerosis: an update on recent and ongoing trials and future strategies

Multiple sclerosis (MS) is the prototype inflammatory autoimmune disorder of the central nervous system and the most common cause of neurological disability in young adults exhibiting considerable clinical, radiological and pathological heterogeneity. Novel insights in the immunopathological processes, advances in biotechnology, development of powerful magnetic resonance imaging technologies together with improvements in clinical trial design led to a variety of evaluable therapeutic approaches. Therapy has changed dramatically over the past decade, yielding significant progress for the treatment of relapsing-remitting and secondary progressive MS. A substantial number of pivotal and preliminary reports continue to demonstrate encouraging new evidence that advances are being made in the care of MS patients. This review summarises recent progress with currently available disease-modifying therapies and - on the basis of present immunopathogenetic concepts - outlines ongoing studies as well as future treatment strategies.