Guidelines for using quantitative measures of brain magnetic resonance imaging abnormalities in monitoring the treatment of multiple sclerosis

Characterizing multiple sclerosis disease progression using a combined structural and functional connectivity metric

PURPOSE

A combined resting state functional connectivity MRI (fcMRI) and diffusion tensor imaging (DTI) metric called structural and functional connectivity index (SFCI) was recently proposed for tracking disease status and progression in multiple sclerosis (MS). The metric combines fcMRI and transverse diffusivity (TD) along different functional pathways involved in principle symptomatic domains of MS. In a longitudinal study of patients with MS receiving the same MS therapy, initial worsening of transcallosal (TC) motor and frontoparietal (FP) cognitive networks, as measured by fcMRI and DTI over the first year was followed by stabilization in the second year of follow-up. In this study we have (i) probed relationships between individual and composite neurological measures of MS with SFCI and its individual components along TC motor and FP cognitive pathways and (ii) compared sensitivity of SFCI to treatment-induced longitudinal changes with each individual imaging measure.

METHODS

Twenty five patients with MS (15 female, age 42 ± 8 y) participated in this study and were scanned at 3 T whole body MRI scanner with diffusion tensor imaging (DTI) and resting-state functional connectivity MRI (fcMRI) scan protocol at baseline and 6, 12, 18 and 24 months after starting fingolimod. fcMRI and TD along TC and FP pathways were combined to form structural and functional connectivity index (SFCI) at each time point. Correlations between individual/combined neurological measures and individual imaging components/SFCI at baseline and were evaluated and compared. In addition, efficacies of individual and combined imaging metrics in tracking network integrity were compared.

RESULTS

Individual TD along the TC pathway was significantly inversely correlated with all individual/composite neurological scores. There were moderate correlations of TC and FP components of SFCI with most of the neurological scores, and the pathway-combined SFCI was significantly correlated with all neurological scores. Trend-level increases of both TC and FP fcMRI were observed during the second year of follow-up, both TC and FP TD increased significantly in the first year and then stabilized during the second year. A trend toward a decrease in combined imaging metrics along TC and FP were observed during the first year, followed by a trend toward an increase in these metrics during the second year, while a significant decrease in SFCI during the first year followed by a significant increase during the second year was observed.

CONCLUSIONS

SFCI was more effective in tracking network integrity/disease progression than individual pathway-specific components, which supports its use as an imaging marker for MS disease status and progression.

Cortical progression patterns in individual ALS patients across multiple timepoints: a mosaic-based approach for clinical use

INTRODUCTION

The majority of imaging studies in ALS infer group-level imaging signatures from group comparisons, as opposed to estimating disease burden in individual patients. In a condition with considerable clinical heterogeneity, the characterisation of individual patterns of pathology is hugely relevant. In this study, we evaluate a strategy to track progressive cortical involvement in single patients by using subject-specific reference cohorts.

METHODS

We have interrogated a multi-timepoint longitudinal dataset of 61 ALS patients to demonstrate the utility of estimating cortical disease burden and the expansion of cerebral atrophy over time. We contrast our strategy to the gold-standard approach to gauge the advantages and drawbacks of our method. We modelled the evolution of cortical integrity in a conditional growth model, in which we accounted for age, gender, disability, symptom duration, education and handedness. We hypothesised that the variance associated with demographic variables will be successfully eliminated in our approach.

RESULTS

In our model, the only covariate which modulated the expansion of atrophy was motor disability as measured by the ALSFRS-r (t(153) = - 2.533, p = 0.0123). Using the standard approach, age also significantly influenced progression of CT change (t(153) = - 2.151, p = 0.033) demonstrating the validity and potential clinical utility of our approach.

CONCLUSION

Our strategy of estimating the extent of cortical atrophy in individual patients with ALS successfully corrects for demographic factors and captures relevant cortical changes associated with clinical disability. Our approach provides a framework to interpret single T1-weighted images in ALS and offers an opportunity to track cortical propagation patterns both at individual subject level and at cohort level.

Changes in structural and functional connectivity during two years of fingolimod therapy for multiple sclerosis

BACKGROUND

Fingolimod, an oral drug, has been reported to reduce relapse rate in multiple sclerosis (MS). However disease progression may still occur in spite of control of inflammation. Functional imbalances within and between cerebral networks associated with disruption of structural and functional network integrity, have been reported in MS. An effective therapy is expected to stabilize such functional network integrity.

OBJECTIVE

The purpose of this study was to investigate changes in structural and resting-state functional connectivity of motor and cognitive networks, and associated changes in neurologic scores in MS, during 2 years of fingolimod therapy.

METHODS

Twenty five subjects with MS were recruited for this study. Subjects were scanned with diffusion tensor imaging (DTI) and resting-state functional connectivity MRI (fcMRI) scan protocol at 3 T with 6-month interval over a period of 2 years. Neurologic performance scores of motor and cognitive performances were also obtained.

RESULTS

DTI measures worsened during the 1st year and then stabilized; any trend of stabilization of fcMRI was delayed until the 2nd year. While motor performance did not change, cognitive performance showed improvement. Several baseline DTI measures correlated with relevant neurologic scores.

CONCLUSION

Initial worsening of motor and cognitive network was reported after 1 year of treatment, but seems DTI and fcMRI measures seem to stabilize after around one year fingolimod therapy.

High levels of serum soluble TWEAK are associated with neuroinflammation during multiple sclerosis

Background

Inflammation and demyelination are the main processes in multiple sclerosis. Nevertheless, to date, blood biomarkers of inflammation are lacking. TWEAK, a transmembrane protein that belongs to the TNF ligand family, has been previously identified as a potential candidate.

Methods

Twenty-eight patients (9 males, 19 females) were prospectively included after a first clinical episode suggestive of multiple sclerosis and clinically followed during 3 years. Fifty-seven healthy controls were also included. TWEAK serum levels and MRI exams including magnetization transfer imaging were performed at baseline, 6- and 12-month follow-up.

Results

TWEAK serum levels were significantly increased in the patient group (mean baseline = 1086 ± 493 pg/mL, mean M6 = 624 ± 302 pg/mL and mean M12 = 578 ± 245 pg/mL) compared to healthy controls (mean = 467 ± 177 pg/mL; respectively p < 0.0001, 0.01 and 0.06). Serum levels of soluble TWEAK were significantly increased during relapses, compared to time periods without any relapse (respectively 935 ± 489 pg/mL and 611 ± 292 pg/mL, p = 0.0005). Moreover, patients presenting at least one gadolinium-enhanced CNS lesion at baseline (n = 7) displayed significantly increased serum TWEAK levels in comparison with patients without any gadolinium-enhanced lesion at baseline (n = 21) (respectively 1421 ± 657 pg/mL vs 975 ± 382 pg/mL; p = 0.02). Finally, no correlation was evidenced between TWEAK serum levels and the extent of brain tissue damage assessed by magnetization transfer ratio.

Conclusions

The present study showed that TWEAK serum levels are increased in MS patients, in relation to the disease activity. This simple and reproducible serum test could be used as a marker of ongoing inflammation, contributing in the follow-up and the care of MS patients. Thus, TWEAK is a promising serum marker of the best window to perform brain MRI, optimizing the disease control in patients.

Clinical Measures of Bulbar Dysfunction in ALS

Bulbar impairment represents a hallmark feature of Amyotrophic Lateral Sclerosis (ALS) that significantly impacts survival and quality of life. Speech and swallowing dysfunction are key contributors to the clinical heterogeneity of ALS and require well-timed and carefully coordinated interventions. The accurate clinical, radiological and electrophysiological assessment of bulbar dysfunction in ALS is one of the most multidisciplinary aspects of ALS care, requiring expert input from speech-language pathologists (SLPs), neurologists, otolaryngologists, augmentative alternative communication (AAC) specialists, dieticians, and electrophysiologists—each with their own evaluation strategies and assessment tools. The need to systematically evaluate the comparative advantages and drawbacks of various bulbar assessment instruments and to develop integrated assessment protocols is increasingly recognized. In this review, we provide a comprehensive appraisal of the most commonly utilized clinical tools for assessing and monitoring bulbar dysfunction in ALS based on the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) evaluation framework. Despite a plethora of assessment tools, considerable geographical differences exist in bulbar assessment practices and individual instruments exhibit considerable limitations. The gaps identified in the literature offer unique opportunities for the optimization of existing and development of new tools both for clinical and research applications. The multicenter validation and standardization of these instruments will be essential for guideline development and best practice recommendations.

Occulomotor Neural Integrator Dysfunction in Multiple Sclerosis: Insights From Neuroimaging

Background: Magnetic resonance imaging is a key diagnostic and monitoring tool in multiple Sclerosis (MS). While the substrates of motor and neuropsychological symptoms in MS have been extensively investigated, nystagmus-associated imaging signatures are relatively under studied. Accordingly, the objective of this study is the comprehensive characterisation of cortical, subcortical, and brainstem involvement in a cohort of MS patients with gaze-evoked nystagmus.

Methods: Patients were recruited from a specialist MS clinic and underwent multimodal neuroimaging including high-resolution structural and diffusion tensor data acquisitions. Morphometric analyses were carried out to evaluate patterns of cortical, subcortical, brainstem, and cerebellar gray matter pathology. Volumetric analyses were also performed to further characterize subcortical gray matter degeneration. White matter integrity was evaluated using axial-, mean-, and radial diffusivity as well as fractional anisotropy.

Results: Whole-brain morphometry highlighted considerable brainstem and cerebellar gray matter atrophy, and the tract-wise evaluation of white matter metrics revealed widespread pathology in frontotemporal and parietal regions. Nystagmus-associated gray matter degeneration was identified in medial cerebellar, posterior medullar, central pontine, and superior collicular regions. Volume reductions were identified in the putamen, thalamus and hippocampus.

Conclusions: Multiple sclerosis is associated with widespread gray matter pathology which is not limited to cortical regions but involves striatal, thalamic, cerebellar, and hippocampal foci. The imaging signature of gaze-evoked nystagmus in MS confirms the degeneration of key structures of the neural integrator network.

MRI results from the European Study on Intravenous Immunoglobulin in Secondary Progressive Multiple Sclerosis (ESIMS)

Background: Monthly application of high-dose intravenous immunoglobulin (IVIG) to patients with secondary progressive multiple sclerosis (MS) showed no clinical benefit in the European Study on Immunoglobulin in MS (ESIMS). Magnetic resonance imaging (MRI) results may provide insights into the morphologic consequences of such treatment. Methods: A total of 318 patients (mean age 44± 7 years) were enrolled in 31 European and Canadian centres and treated monthly with 1 g/kg body weight of IVIG or equivalent amounts of albumin 0.1% for 27 months. MRI was performed at baseline and after 12 and 24 months and comprised of conventional dual-echo T2-weighted and T1-weighted scans before and after application of 0.1 mmol/kg Gd-DTPA. Results: Similar to clinical variables, MRI measures at baseline were well comparable between treatment groups except for a somewhat lower mean number of contrast-enhancing lesions and number of active scans in IVIG-treated patients. Over the trial period there was almost no change of the T2-lesion load and the ‘black hole’ volume in both treatment groups and the cumulative number of contrast-enhancing lesions were similar. There was only a trend for fewer new or enlarged T2-lesions in IVIG patients, which disappeared after correction for the imbalance in the number of contrast-enhancing lesions at baseline. Brain volume in terms of a partial cerebral fraction decreased significantly less with IVIG than placebo treatment (final visit:-0.62± 0.88% versus-0.88± 0.91%; P= 0.009). This difference remained statistically significant with correction for active lesions at baseline (P= 0.02) and was seen primarily in male patients and those with an Expanded Disability Status Scale score ≥ 6 and no relapses in the two years before the study. Conclusion: The absence of significant differences in conventional MRI measures between both treatment groups parallels the negative clinical results of ESIMS. The causes for and possible long-term clinical effects of a lower rate of brain volume loss in IVIG patients should be explored further.

"RADIOTRANSCRIPTOMICS": A synergy of imaging and transcriptomics in clinical assessment

Recent advances in quantitative imaging and "omics" technology have generated a wealth of mineable biological "big data". With the push towards a P4 "predictive, preventive, personalized, and participatory" approach to medicine, researchers began integrating complementary tools to further tune existing diagnostic and therapeutic models. The field of radiogenomics has long pioneered such multidisciplinary investigations in neuroscience and oncology, correlating genotypic and phenotypic signatures to study structural and functional changes in relation to altered molecular behavior. Given the innate dynamic nature of complex disorders and the role of environmental and epigenetic factors in pathogenesis, the transcriptome can further elucidate serial modifications undetected at the genome level. We therefore propose "radiotranscriptomics" as a new member of the P4 medicine initiative, combining transcriptome information, including gene expression and isoform variation, and quantitative image annotations.

Multiple sclerosis

Due to its sensitivity to the different multiple sclerosis (MS)-related abnormalities, magnetic resonance imaging (MRI) has become an established tool to diagnose MS and to monitor its evolution. MRI has been included in the diagnostic workup of patients with clinically isolated syndromes suggestive of MS, and ad hoc criteria have been proposed and are regularly updated. In patients with definite MS, the ability of conventional MRI techniques to explain patients' clinical status and progression of disability is still suboptimal. Several advanced MRI-based technologies have been applied to estimate overall MS burden in the different phases of the disease. Their use has allowed the heterogeneity of MS pathology in focal lesions, normal-appearing white matter and gray matter to be graded in vivo. Recently, additional features of MS pathology, including macrophage infiltration and abnormal iron deposition, have become quantifiable. All of this, combined with functional imaging techniques, is improving our understanding of the mechanisms associated with MS evolution. In the near future, the use of ultrahigh-field systems is likely to provide additional insight into disease pathophysiology. However, the utility of advanced MRI techniques in clinical trial monitoring and in assessing individual patients' response to treatment still needs to be assessed.

Nonconventional MRI and microstructural cerebral changes in multiple sclerosis

MRI has become the most important paraclinical tool for diagnosing and monitoring patients with multiple sclerosis (MS). However, conventional MRI sequences are largely nonspecific in the pathology they reveal, and only provide a limited view of the complex morphological changes associated with MS. Nonconventional MRI techniques, such as magnetization transfer imaging (MTI), diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) promise to complement existing techniques by revealing more-specific information on microstructural tissue changes. Past years have witnessed dramatic advances in the acquisition and analysis of such imaging data, and numerous studies have used these tools to probe tissue alterations associated with MS. Other MRI-based techniques-such as myelin-water imaging, (23)Na imaging, magnetic resonance elastography and magnetic resonance perfusion imaging-might also shed new light on disease-associated changes. This Review summarizes the rapid technical progress in the use of MRI in patients with MS, with a focus on nonconventional structural MRI. We critically discuss the present utility of nonconventional MRI in MS, and provide an outlook on future applications, including clinical practice. This information should allow appropriate selection of advanced MRI techniques, and facilitate their use in future studies of this disease.

Magnetic resonance outcome measures in multiple sclerosis trials: time to rethink?

PURPOSE OF REVIEW

We summarize MRI measures currently available to assess treatment efficacy and safety in multiple sclerosis (MS) clinical trials and discuss novel metrics that could enter the clinical arena in the near future.

RECENT FINDINGS

In relapsing remitting MS, MRI measures of disease activity (new T2 and gadolinium-enhancing lesions) provide a good surrogacy of treatment effect on relapse rate and disability progression; however, their value in progressive MS remains elusive. For the progressive disease forms, these measures need to be combined with quantities assessing the extent of irreversible tissue loss, which have already been introduced in some clinical trials (e.g., evolution of active lesions into permanent black holes and brain atrophy). Novel measures (e.g., quantification of gray matter and spinal cord atrophy) have demonstrated a great value in explaining patients' clinical outcome, but still need to be fully validated. Despite showing promise, evaluations of cortical lesions, of microscopic tissue abnormalities, and of functional cortical reorganization are still some way off for monitoring of treatment effects.

SUMMARY

Trial outcomes in MS should include measures of inflammation and neurodegeneration, which should be combined according to the disease clinical phenotype, phase of the study, and the supposed mechanism of action of the drug tested.

Disease-modifying drugs for the early treatment of multiple sclerosis

The introduction of new immunomodulatory therapies such as, interferon-beta, glatiramer acetate (Copaxone, Teva Pharmaceutical Industries) and mitoxantrone (Ralenova, Wyeth Pharma; Novantrone, Immunex Corp.) has considerably improved the therapeutic options for patients with multiple sclerosis. These agents have been shown to reduce relapse rate, slow down progression of disability and prevent the accumulation of magnetic resonance imaging lesion load in clinically definite multiple sclerosis. Moreover, two formulations of interferon-beta delayed conversion into clinically definite multiple sclerosis in patients with clinically isolated syndromes suggestive of multiple sclerosis. Since axonal damage leading to irreversible neurological disability is already present early at the onset of the disease, immunomodulatory therapy should start as soon as possible. This article reviews the arguments for the early initiation of therapy and provides an overview of clinical studies dealing with the early treatment of multiple sclerosis.

Insights from magnetic resonance imaging

Recent years have witnessed impressive advancements in the use of magnetic resonance imaging (MRI) for the assessment of patients with multiple sclerosis (MS). Complementary to the clinical evaluation, conventional MRI (cMRI) provides crucial pieces of information for the diagnosis of MS, the understanding of its natural history, and monitoring the efficacy of experimental treatments. Measures derived from cMRI present clear advantages over the clinical assessment, including their more objective nature and an increased sensitivity to MS-related changes. However, the correlation between these measures and the clinical manifestations of the disease remains weak, and this can be explained, at least partially, by the limited ability of cMRI to characterize and quantify the heterogeneous features of MS pathology. Quantitative MR-based techniques have the potential to overcome the limitations of cMRI. Magnetization transfer MRI, diffusion-weighted and diffusion tensor MRI with fiber tractography, proton magnetic resonance spectroscopy, T1 and T2 relaxation time measurement, and functional MRI are contributing to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. All conventional and nonconventional MR techniques will benefit from the use of high-field MR systems (3.0T or more).

Guidelines from The Italian Neurological and Neuroradiological Societies for the use of magnetic resonance imaging in daily life clinical practice of multiple sclerosis patients

MRI is highly sensitive in detecting focal white matter lesions in multiple sclerosis (MS). For this reason, it has been formally included in the diagnostic workup of patients with clinically isolated syndromes suggestive of MS, through the definition of ad hoc sets of criteria to show disease dissemination in space and time. MRI is used in virtually all clinical trials of the disease as a surrogate measure of treatment response. Several guidelines have been published to help characterizing the imaging features on conventional MR sequences of "typical" MS lesions and work has also been performed to identify "red flags" which should alert the clinicians to exclude possible alternative conditions. Despite this, the application of the available guidelines and criteria in daily life clinical practice is still limited and varies among and within countries (including Italy) due to regulatory issues and heterogeneity of MRI facilities. It is crucial for neurologists and neuroradiologists to become familiar with these criteria to improve the quality of their diagnostic assessment. In patients with established MS, the main problem is to define standard procedures for monitoring the course of the disease and treatment response. This review aims at providing daily life guidelines to clinicians for a correct application of MRI in the workup of patients suspected of having MS as well as in the monitoring of disease evolution in those with established MS. It also offers clues for the standardization of MRI studies and relative reporting to be applied at a national level.

Mitoxantrone for multiple sclerosis

BACKGROUND

This is an updated Cochrane review of the previous published version.Mitoxantrone (MX) has been shown to be moderately effective in reducing the clinical outcome measures of disease activity in multiple sclerosis (MS) patients.

OBJECTIVES

The main objective was to assess the efficacy and safety of MX compared to a control group in relapsing-remitting (RRMS), progressive relapsing (PRMS) and secondary progressive (SPMS) MS participants.

SEARCH METHODS

We searched the Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System Group Specialised Register (June 2012) and reference lists of articles. We also undertook handsearching and contacted trialists and pharmaceutical companies.

SELECTION CRITERIA

Randomised, double-blinded, controlled trials (RCTs) comparing the administration of MX versus placebo or MX plus steroids treatment versus placebo plus steroids treatment were included.

DATA COLLECTION AND ANALYSIS

The review authors independently selected articles for inclusion. They independently extracted clinical, safety and magnetic resonance imaging (MRI) data, resolving disagreements by discussion. Risk of bias was evaluated to assess the quality of the studies. Treatment effect was measured using odds ratios (OR) with 95% confidence intervals (CI) for the binary outcomes and mean differences (MD) with 95% CI for the continuous outcomes. If heterogeneity was absent, a fixed-effect model was used.

MAIN RESULTS

Three trials were selected and 221 participants were included in the analyses. MX reduced the progression of disability at two years follow-up (proportion of participants with six months confirmed progression of disability (OR 0.30, 95% CI 0.09 to 0.99 and MD -0.36, 95% CI- 0.70 to -0.02; P = 0.04)). Significant results were found regarding the reduction in annualised relapse rate (MD -0.85, 95% CI -1.47 to -0.23; P = 0.007), the proportion of patients free from relapses at one year (OR 7.13, 95% CI 2.06 to 24.61; P = 0.002) and two years (OR 2.82, 95% CI 1.54 to 5.19; P = 0.0008), and the number of patients with active MRI lesions at six months or one year only (OR 0.24, 95% CI 0.10 to 0.57; P = 0.001). Side effects reported in the trials (amenorrhoea, nausea and vomiting, alopecia and urinary tract infections) were more frequent in treated patients than in controls, while no major adverse events have been reported. These results should be considered with caution because of the heterogeneous characteristics of included trials in term of drug dosage, inclusion criteria and quality of included trials. Moreover, it was not possible to estimate the long-term efficacy and safety of MX.

AUTHORS' CONCLUSIONS

MX shows a significant but partial efficacy in reducing the risk of MS progression and the frequency of relapses in patients affected by worsening RRMS, PRMS and SPMS in the short-term follow-up (two years). No major neoplastic events or symptomatic cardiotoxicity related to MX have been reported; however studies with longer follow-up (not included in this review) have raised concerns about the risk of systolic disfunction (˜12%) and therapy-related acute leukaemias (0.8%), which are increasingly reported in the literature.MX should be limited to treating patients with worsening RRMS and SPMS and with evidence of persistent inflammatory activity after a careful assessment of the individual patients' risk and benefit profiles. Assessment should also consider the present availability of alternative therapies with less severe adverse events.

Recommendations to improve imaging and analysis of brain lesion load and atrophy in longitudinal studies of multiple sclerosis

Focal lesions and brain atrophy are the most extensively studied aspects of multiple sclerosis (MS), but the image acquisition and analysis techniques used can be further improved, especially those for studying within-patient changes of lesion load and atrophy longitudinally. Improved accuracy and sensitivity will reduce the numbers of patients required to detect a given treatment effect in a trial, and ultimately, will allow reliable characterization of individual patients for personalized treatment. Based on open issues in the field of MS research, and the current state of the art in magnetic resonance image analysis methods for assessing brain lesion load and atrophy, this paper makes recommendations to improve these measures for longitudinal studies of MS. Briefly, they are (1) images should be acquired using 3D pulse sequences, with near-isotropic spatial resolution and multiple image contrasts to allow more comprehensive analyses of lesion load and atrophy, across timepoints. Image artifacts need special attention given their effects on image analysis results. (2) Automated image segmentation methods integrating the assessment of lesion load and atrophy are desirable. (3) A standard dataset with benchmark results should be set up to facilitate development, calibration, and objective evaluation of image analysis methods for MS.

Multicentre imaging measurements for oncology and in the brain

Multicentre imaging studies of brain tumours (and other tumour and brain studies) can enable a large group of patients to be studied, yet they present challenging technical problems. Differences between centres can be characterised, understood and minimised by use of phantoms (test objects) and normal control subjects. Normal white matter forms an excellent standard for some MRI parameters (e.g. diffusion or magnetisation transfer) because the normal biological range is low (<2-3%) and the measurements will reflect this, provided the acquisition sequence is controlled. MR phantoms have benefits and they are necessary for some parameters (e.g. tumour volume). Techniques for temperature monitoring and control are given. In a multicentre study or treatment trial, between-centre variation should be minimised. In a cross-sectional study, all groups should be represented at each centre and the effect of centre added as a covariate in the statistical analysis. In a serial study of disease progression or treatment effect, individual patients should receive all of their scans at the same centre; the power is then limited by the within-subject reproducibility. Sources of variation that are generic to any imaging method and analysis parameters include MR sequence mismatch, B(1) errors, CT effective tube potential, region of interest generation and segmentation procedure. Specific tissue parameters are analysed in detail to identify the major sources of variation and the most appropriate phantoms or normal studies. These include dynamic contrast-enhanced and dynamic susceptibility contrast gadolinium imaging, T(1), diffusion, magnetisation transfer, spectroscopy, tumour volume, arterial spin labelling and CT perfusion.

MR imaging of multiple sclerosis

Owing to its ability to depict the pathologic features of multiple sclerosis (MS) in exquisite detail, conventional magnetic resonance (MR) imaging has become an established tool in the diagnosis of this disease and in monitoring its evolution. MR imaging has been formally included in the diagnostic work-up of patients who present with a clinically isolated syndrome suggestive of MS, and ad hoc diagnostic criteria have been proposed and are updated on a regular basis. In patients with established MS and in those participating in treatment trials, examinations performed with conventional MR pulse sequences provide objective measures to monitor disease activity and progression; however, they have a limited prognostic role. This has driven the application of newer MR imaging technologies, including higher-field-strength MR units, to estimate overall MS burden and mechanisms of recovery in patients at different stages of the disease. These techniques have allowed in vivo assessment of the heterogeneity of MS pathologic features in focal lesions and in normal-appearing tissues. More recently, some of the finer details of MS, including macrophage infiltration and abnormal iron deposition, have become quantifiable with MR imaging. The utility of these modern MR techniques in clinical trial monitoring and in the assessment of the individual patient's response to treatment still need to be evaluated.

Disease modifying agents for multiple sclerosis

Objective:

To summarize major clinical trials which evaluate the efficacy and safety data of approved disease modifying agents for the treatment of various types of multiple sclerosis.

Data Sources:

A MEDLINE (1966 to August 2008) search of clinical trials using the terms multiple sclerosis, interferon, glatiramer, mitoxantrone and natalizumab was performed. A manual bibliographic search was also conducted. English-language articles identified from the searches were evaluated. New agents under investigation in phase 3 clinical trials were identified using www.clinicaltrials.gov.

Study Selection & Data Extraction:

Relevant information was identified and selected based on clinical relevance and evidence-based strength. Prescribing information leaflets were used to provide usual dosage, contraindications, precautions, monitoring parameters and other relevant drug-specific information.

Data Synthesis:

Interferon beta products are more efficacious for the treatment of relapsing-remitting multiple sclerosis. Interferon beta 1-b also delayed the time to diagnosis of definite multiple sclerosis and reduced brain lesion burden in patients with clinical isolated syndrome. Glatiramer and natalizumab have both established efficacy in relapsing forms of multiple sclerosis; whereas mitoxantrone is more commonly used in patients with advanced disease. There are limited data the comparative efficacy among different disease modifying agents. New agents currently under investigation have showed promising results and may offer more treatment options in the future.

Conclusions:

MS is a complex and devastating disease with challenging treatment considerations and approaches. Interferon beta products continue to be the mainstay of therapy in many patients, however, other treatments are proving to be at least as effective in the management of various types of MS. Newer compounds are being developed and studied with much anticipation and promise for the clinical management of the disease.

Improved detection of active multiple sclerosis lesions: 3D subtraction imaging

PURPOSE

To examine the benefits of using near-isotropic single-slab three-dimensional (3D) magnetic resonance (MR) imaging for the creation of subtraction images and to evaluate their performance in the detection of active multiple sclerosis (MS) brain lesions in comparison with two-dimensional (2D) subtraction images.

MATERIALS AND METHODS

The study protocol was approved by the local ethics review board and all subjects gave written informed consent before investigation. Three-dimensional MR sequences, including double inversion-recovery, fluid-attenuated inversion recovery, T2-weighted, and T1-weighted magnetization-prepared rapid acquisition gradient-echo (MP-RAGE), and corresponding 2D sequences were performed twice in 14 patients (eight women, six men; mean age, 37.6 years) with MS and nine age-matched healthy control subjects (three women, six men; mean age, 31.7 years). Active lesions were scored by two independent raters, followed by a consensus reading. Lesion counts were evaluated by using negative binomial regression; interrater agreement was evaluated by using intraclass correlation coefficient.

RESULTS

Three-dimensional subtraction images had less residual misregistration and flow artifacts and depicted higher numbers of active lesions with greater interobserver agreement compared with 2D subtraction images. Among the 3D sequences, MP-RAGE subtraction imaging enabled detection of a significantly higher mean number of positive active MS lesions compared with 2D subtraction imaging (2.8 versus 1.7, P = .012), particularly infratentorial lesions (0.6 vs 0.1, P < .05), and a substantially higher (nonsignificant) mean number of small (<3 mm) lesions (0.6 vs 0.1, P > .05).

CONCLUSION

Three-dimensional subtraction imaging, after image registration, produced better image quality, leading to increased detection of active MS lesions with greater interobserver agreement in comparison with 2D subtraction imaging; 3D MP-RAGE subtraction imaging represents a promising technique to increase sensitivity in ascertaining lesion dissemination in time and increase the power of MR imaging metrics for the evaluation of treatment effects in clinical trials.

Multi-Contrast, Isotropic, Single-Slab 3D MR Imaging in Multiple Sclerosis

To describe signal and contrast properties of an isotropic, single-slab 3D dataset [double inversion-recovery (DIR), fluid-attenuated inversion recovery (FLAIR), T2, and T1-weighted magnetization prepared rapid acquisition gradient-echo (MPRAGE)] and to evaluate its performance in detecting multiple sclerosis (MS) brain lesions compared to 2D T2-weighted spin-echo (T2SE). All single-slab 3D sequences and 2D-T2SE were acquired in 16 MS patients and 9 age-matched healthy controls. Lesions were scored independently by two raters and characterized anatomically. Two-tailed Bonferroni-corrected Student's t-tests were used to detect differences in lesion detection between the various sequences per anatomical area after log-transformation. In general, signal and contrast properties of the 3D sequences enabled improved detection of MS brain lesions compared to 2D-T2SE. Specifically, 3D-DIR showed the highest detection of intracortical and mixed WM-GM lesions, whereas 3D-FLAIR showed the highest total number of WM lesions. Both 3D-DIR and 3D-FLAIR showed the highest number of infratentorial lesions. 3D-T2 and 3D-MPRAGE did not improve lesion detection compared to 2D-T2SE. Multi-contrast, isotropic, single-slab 3D MRI allowed an improved detection of both GM and WM lesions compared to 2D-T2SE. A selection of single-slab 3D contrasts, for example, 3D-FLAIR and 3D-DIR, could replace 2D sequences in the radiological practice.

User interface of a teleradiology system for the MR assessment of multiple sclerosis

The aim of this study was to assess the image display of a web-based teleradiology system that uses a common web browser and has no need of proprietary applets, plug-ins, or dedicated software for DICOM display. The teleradiology system (TS) is connected to the Internet by ADSL and to radiological modalities using the DICOM standard with TCP/IP. Images were displayed on a PC through Internet connection with the remote TS using a common web browser. MS lesion number and volume in T1- and T2-weighted images (T1w and T2w, respectively) of 30 brain MR studies were quantified using both the TS and a conventional software. Wilcoxon signed ranks test and intraclass correlation coefficient (ICC) were used to assess the variability and concordance between intra- and inter-observer and TS and conventional DICOM viewer, setting significance at p < 0.05. No significant differences in T1w and T2w volumes between the TS and the conventional software were found by either operator. The ICC results showed a high level of inter-operator agreement in volume estimation in T1w and T2w images using the two systems. Quantitative assessment of MS lesion volumes in T1w and T2w images with a user interface of a teleradiology system that allows the consultation by means of a common web browser, without the need for proprietary plug-ins, applets, or dedicated software for DICOM display showed no significant differences from, and almost complete agreement with, conventional DICOM viewers.

Randomized study of interferon beta-1a, low-dose azathioprine, and low-dose corticosteroids in multiple sclerosis

Background

Studies evaluating interferon beta (IFNβ) for multiple sclerosis (MS) showed only partial efficacy. In many patients, IFNβ does not halt relapses or disability progression. One strategy to potentially enhance efficacy is to combine IFNβ with classical immunosuppressive agents, such as azathioprine (AZA) or corticosteroids, commonly used for other autoimmune disorders.

Objective

The Avonex–Steroids–Azathioprine study was placebo-controlled trial and evaluated efficacy of IFNβ-1a alone and combined with low-dose AZA alone or low-dose AZA and low-dose corticosteroids as initial therapy.

Methods

A total of 181 patients with relapsing–remitting MS (RRMS) were randomized to receive IFNβ-1a 30 μg intramuscularly (IM) once weekly, IFNβ-1a 30 μg IM once weekly plus AZA 50 mg orally once daily, or IFNβ-1a 30 μg IM once weekly plus AZA 50 mg orally once daily plus prednisone 10 mg orally every other day. The primary end point was annualized relapse rate (ARR) at 2 years. Patients were eligible for enrollment in a 3-year extension.

Results

At 2 years, adjusted ARR was 1.05 for IFNβ-1a, 0.91 for IFNβ-1a plus AZA, and 0.73 for combination. The cumulative probability of sustained disability progression was 16.8% for IFNβ-1a, 20.7% for IFNβ-1a plus AZA, and 17.5% for combination. There were no statistically significant differences among groups for either measure at 2 and 5 years. Percent T2 lesion volume change at 2 years was significantly lower for combination (+14.5%) versus IFNβ-1a alone (+30.3%, P < 0.05). Groups had similar safety profiles.

Conclusion

In IFNβ-naïve patients with early active RRMS, combination treatment did not show superiority over IFNβ-1a monotherapy.

Cerebrospinal fluid biomarkers in multiple sclerosis

In patients with multiple sclerosis (MS) intensive efforts are directed at identifying biomarkers in bodily fluids related to underlying disease mechanisms, disease activity and progression, and therapeutic response. Besides MR imaging parameters cerebrospinal fluid (CSF) biomarkers provide important and specific information since changes in the CSF composition may reflect disease mechanisms inherent to MS. The different cellular and protein-analytical methods of the CSF and the recommended standard of the diagnostic CSF profile in MS are described. A brief update on possible CSF biomarkers that might reflect key pathological processes of MS such as inflammation, demyelination, neuroaxonal loss, gliosis and regeneration is provided.

Biomarkers and imaging: physics and chemistry for noninvasive analyses

The era of ‘modern medicine’ has changed its name to ‘molecular medicine’, and reflects a new age based on personalized medicine utilizing molecular biomarkers in the diagnosis, staging and monitoring of therapy. Alzheimer’s disease has a classical biomarker determined at autopsy with the histologic staining of amyloid accumulation in the brain. Today we can diagnose Alzheimer’s disease using the same classical pathologic biomarker, but now using a noninvasive imaging probe to image the amyloid deposition in a patient and potentially provide treatment strategies and measure their effectiveness. Molecular medicine is the exploitation of biomarkers to detect disease before overt expression of pathology. Physicians can now find, fight and follow disease using imaging, and the need for other disease biomarkers is in high demand. This review will discuss the innovative physical and molecular biomarker probes now being developed for imaging systems and we will introduce the concepts needed for validation and regulatory acceptance of surrogate biomarkers in the detection and treatment of disease.

Long-term study of brain 1H-MRS study in multiple sclerosis: effect of glatiramer acetate therapy on axonal metabolic function and feasibility of long-Term H-MRS monitoring in multiple sclerosis

Glatiramer acetate (GA) has several putative mechanisms of action with the potential of limiting sublethal axonal injury in the central nervous system (CNS). Brain proton magnetic resonance spectroscopy ((1)H-MRS) allows in vivo examination of axonal integrity by quantifying the neuronal marker N-acetylaspartate (NAA), often expressed as a ratio to creatine (Cr). We showed that treatment with GA led to improvement in NAA/Cr over a 2-year period. We now report the results of this ongoing study after 4 years of annual brain (1)H-MRS examinations. Compared to baseline, at year 4, patients receiving continuous GA therapy showed a 12.7% increase in NAA/Cr and (P= .03) in the multivoxel brain volume of interest (VOI) studied and by 9.6% (P= .04) in the normal-appearing white matter within the VOI. Three patients in the control group who began therapy with GA during the course of the study showed similar increases in NAA/Cr after the first year of therapy. These data support the long-term effect of GA on maintaining axonal metabolic function and protection from sublethal injury as well as the feasibility of employing brain (1)H-MRS in long-term investigative studies in MS.

Subtraction MR images in a multiple sclerosis multicenter clinical trial setting

PURPOSE

To explore the applicability of subtraction magnetic resonance (MR) images to (a) detect active multiple sclerosis (MS) lesions, (b) directly quantify lesion load change, and (c) detect treatment effects (distinguish treatment arms) in a placebo-controlled multicenter clinical trial by comparing the subtraction scheme with a conventional pair-wise comparison of nonregistered MR images.

MATERIALS AND METHODS

Forty-six pairs of MR studies in 40 patients (31 women; mean age, 31.9 years) from a multicenter clinical trial were used. The clinical trial was approved by local ethics review boards, and all subjects gave written informed consent. Active MS lesions were scored by two independent raters, and lesion load measurements were conducted by using semiautomated software. Lesion counts were evaluated by using the Wilcoxon signed rank test, interrater agreement was evaluated by using the intraclass correlation coefficient (ICC), and treatment (interferon beta-1b) effect was evaluated by using the Mann-Whitney U test.

RESULTS

When subtraction images were used, there was a 1.7-fold increase in the detection of positive active lesions, as compared with native image pairs, and significantly greater interobserver agreement (ICC = 0.98 vs 0.91, P < .001). Subtraction images also allowed direct quantification of positive disease activity, a measure that provided sufficient power to distinguish treatment arms (P = .012) compared with the standard measurement of total lesion load change on native images (P = .455).

CONCLUSION

MR image subtraction enabled detection of higher numbers of active MS lesions with greater interobserver agreement and exhibited increased power to distinguish treatment arms, as compared with a conventional pair-wise comparison of nonregistered MR images.

Clinical and conventional MRI predictors of disability and brain atrophy accumulation in RRMS. A large scale, short-term follow-up study

To assess the value of clinical and MRI variables in predicting short-term brain atrophy accumulation and clinical evolution in a large cohort of patients with RRMS, we studied a cohort of 548 patients, previously enrolled as a placebo arm of a 14-month, double-blind trial of oral glatiramer acetate (GA). A logistic regression model with EDSS progression as the dependent variable was built to assess baseline clinical and MRI variables associated with clinical worsening during follow-up. In 466 patients with complete central brain atrophy assessment, another linear regression model with percentage central brain volume change (PCBVC) as the dependent variable was built to assess baseline clinical and MRI variables associated with atrophy development.A total of 80 patients (15%) had EDSS progression over the follow-up period. Factors independently predicting the probability to have a clinical progression were lower EDSS (OR = 0.78, 95% CI = 0.62-0.97 p = 0.02) and higher T2 LL (OR = 1.022, 95% CI = 1.006-1.038, p = 0.007) at baseline. In the 466 patients with atrophy assessment, PCBVC declined, on average, by -2.0% (SD = 2.8) (p < 0.001) over the follow-up. The multivariate PCBVC analysis revealed that the PCBVC decrease was independently correlated with higher EDSS (p = 0.03) and T2 LL (p = 0.005) at baseline. The squared correlation coefficients of the composite scores made up of EDSS and T2 LL considered together were able to explain only 3 % of the variance in disability progression and only 4 % of the variance of PCBVC.In RRMS patients, clinical and conventional MRI findings at baseline only modestly predict shortterm accumulation of brain atrophy and disability. These data confirm the need to develop clinical and MRI measures more sensitive towards the more disabling aspects of the disease.

Multi-contrast, isotropic, single-slab 3D MR imaging in multiple sclerosis

To describe signal and contrast properties of an isotropic, single-slab 3D dataset [double inversion-recovery (DIR), fluid-attenuated inversion recovery (FLAIR), T2, and T1-weighted magnetization prepared rapid acquisition gradient-echo (MPRAGE)] and to evaluate its performance in detecting multiple sclerosis (MS) brain lesions compared to 2D T2-weighted spin-echo (T2SE). All single-slab 3D sequences and 2D-T2SE were acquired in 16 MS patients and 9 age-matched healthy controls. Lesions were scored independently by two raters and characterized anatomically. Two-tailed Bonferroni-corrected Student's t-tests were used to detect differences in lesion detection between the various sequences per anatomical area after log-transformation. In general, signal and contrast properties of the 3D sequences enabled improved detection of MS brain lesions compared to 2D-T2SE. Specifically, 3D-DIR showed the highest detection of intracortical and mixed WM-GM lesions, whereas 3D-FLAIR showed the highest total number of WM lesions. Both 3D-DIR and 3D-FLAIR showed the highest number of infratentorial lesions. 3D-T2 and 3D-MPRAGE did not improve lesion detection compared to 2D-T2SE. Multi-contrast, isotropic, single-slab 3D MRI allowed an improved detection of both GM and WM lesions compared to 2D-T2SE. A selection of single-slab 3D contrasts, for example, 3D-FLAIR and 3D-DIR, could replace 2D sequences in the radiological practice.

Incorporating domain knowledge into the fuzzy connectedness framework: application to brain lesion volume estimation in multiple sclerosis

A method for incorporating prior knowledge into the fuzzy connectedness image segmentation framework is presented. This prior knowledge is in the form of probabilistic feature distribution and feature size maps, in a standard anatomical space, and "intensity hints" selected by the user that allow for a skewed distribution of the feature intensity characteristics. The fuzzy affinity between pixels is modified to encapsulate this domain knowledge. The method was tested by using it to segment brain lesions in patients with multiple sclerosis, and the results compared to an established method for lesion outlining based on edge detection and contour following. With the fuzzy connections (FC) method, the user is required to identify each lesion with a mouse click, to provide a set of seed pixels. The algorithm then grows the features from the seeds to define the lesions as a set of objects with fuzzy connectedness above a preset threshold. The FC method gave improved interobserver reproducibility of lesion volumes, and the set of pixels determined to be lesion was more consistent compared to the contouring method. The operator interaction time required to evaluate one subject was reduced from an average of 111 min with contouring to 16 min with the FC method.

Interferon Beta-1b may reverse axonal dysfunction in multiple sclerosis

Progression of the disability of multiple sclerosis (MS) is thought to be related to axonal damage that is seen even in normal appearing white matter (NAWM) of patients' brains. Interferon beta (IFNβ) treatment for MS reduces the frequency of clinical exacerbations and the appearance of new inflammatory demyelinating lesions on magnetic resonance imaging (MRI). However, the effect of IFNβ treatment on axonal damage in MS is not known. The present study aimed to assess the effect of IFNβ on axonal function by comparing the data from localised single voxel proton MR spectroscopy (MRS) performed on eight MS patients given IFNβ-1b treatment and 11 untreated patients. Brain MRI and MRS were performed before the initiation of IFNβ-1b treatment and 24 months after treatment initiation. Levels of N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine (Cr) were calculated as the areas under their peaks shown on MRS and the ratios of NAA/Cr and Cho/Cr were calculated. In the patients treated with IFNβ-1b there was a significant increase in the ratio of NAA/Cr in NAWM (p=0.028) at 24 months after the initiation of treatment. In contrast, there was no significant change in the NAA/Cr ratio in the untreated patients. These results suggest that IFNβ-1b treatment might recover axonal function in NAWM of MS patients.

Effect of intravenous methylprednisolone on the number, size and confluence of plaques in relapsing-remitting multiple sclerosis

The aim of the present study was to evaluate whether intravenous methylprednisolone (IVMP) pulses affect the confluence and enlargement of T2 lesions in the long term in patients with relapsing-remitting (RR) multiple sclerosis (MS). Of 88 RR MS patients, randomly assigned to regular pulses of IVMP (1 g/day for 5 days with an oral prednisone taper) or IVMP on the same dose schedule only for relapses, and followed up without other disease-modifying drug therapy for 5 years, 81 patients completed the trial as planned. Pulsed IVMP was given every 4 months for 3 years, and then every 6 months for the subsequent 2 years. Calculations were performed for number, size and lesion volume (LV) of T2- and confluent T2-lesions. At study entry, the number, size and LV of T2- and confluent T2-lesions were well matched in the two study arms. At the end of the study, patients who received IVMP pulses every 4-6 months for 5 years had significantly fewer confluent T2 lesions (105 vs. 270, p<0.0001), lower confluent T2-LV (5.4 ml vs. 17.4 ml, p<0.00001), fewer large T2 lesions (>10 mm) (165 vs. 541, p<0.00001), and lower T2-LV/N degrees T2 lesion index (0.52 vs. 1.1, p=0.007) when compared to patients who received IVMP only for relapses. There were more small T2 lesions (1082 vs. 288, p<0.000001) in the IVMP pulsed arm. Patients who received higher total doses of IVMP showed the smallest changes in confluent T2-LV during the study. This study suggests that treatment with pulses of IVMP may prevent the confluence of T2 lesions, which may in turn contribute to slower progression of disability in the long term. However, pulsed IVMP treatment did not significantly slow down accumulation of overall T2-LV and there were more smaller T2 lesions in the IVMP pulsed arm at the end of the study.

Pooled historical MRI data as a basis for research in multiple sclerosis--a statistical evaluation

Pooled data from placebo groups of different trials can serve as historical control for ongoing or future therapeutic studies and as a reference for power calculations. In order to assess their usefulness for this purpose, we investigated the degree of heterogeneity of placebo arm data from 14 controlled studies included in the database of the Sylvia Lawry Centre for Multiple Sclerosis Research. Since different criteria for the inclusion/exclusion of patients were used in these studies, an attempt was made to adjust the distribution of magnetic resonance imaging (MRI) measures for the differences in the study populations. The analyses showed that, even after adjustment, significant differences remained. This heterogeneity does not reduce the usefulness of the database for statistical analysis of inter-relationships between variables, provided that it is explicitly taken into account as a stratification factor. However, care must be taken when trying to compare the results of a newly treated group with the patients of this pool. Heterogeneity in some MRI variables was greatly reduced when only studies from the same image analysis centre were compared.

Detection of cortical lesions is dependent on choice of slice thickness in patients with multiple sclerosis

Understanding the importance of cortical lesions in MS pathogenesis has changed. Histopathologic studies using new immunohistochemical methods show that cortical lesions can be detected more frequently than previously reported. Newer MRI sequences also detect cortical lesions more accurately. The aim of this study was to evaluate whether the effect of slice thickness (th) is an important factor for detection of cortical lesions in patients with multiple sclerosis (MS). We aimed also to investigate the relationship of cortical lesions with clinical status or other MRI variables. Forty-one patients with relapsing-remitting (RR) MS (11 males, 30 females with mean EDSS 2.3) underwent scans of Two-dimensional (2D)-fluid-attenuated inversion recovery (FLAIR) and 3D-T1-WI at 1.5-, 3-, and 5-mm slice thicknesses on 1.5-T MRI. Cortical and juxtacortical lesions were volumetrically assessed using a semiautomated method. 2D-FLAIR and 3D-T1-WI were coregistered and the matrix of the neocortical volume (NCV) segmentation mask (SIENAX-generated) was used to classify the location of the cortical-subcortical lesions. Cortical lesions fell into three classes: (1) class 1 were defined as lesions located in the NCV, (2) class 2 were juxtacortical lesions in contact with the NCV mask, and (3) class 3 were cortical-juxtacortical lesions situated in both regions. We measured NCV and normalized gray matter (GM) volume as well. We used partial correlation and multiple regressions to investigate the relationship between cortical lesions and other clinical and MRI variables. Of the total T2-lesion volume (T2-LV) measured on 1.5-mm th scans (mean 16108 mm(3)), cortical lesions represented 2.4% (276 mm(3)), juxtacortical lesions 6.1% (760 mm(3)), and cortical-juxtacortical 3.7% (491 mm(3)). Compared to 1.5-mm th scan, cortical LV was reduced by -28.3%, p < 0.001 on 3-mm th and by -40.78%, p < 0.001 on 5-mm th scans. Results for juxtacortical LV were for 3-mm th scans (-17.9%, p < 0.01) and for 5-mm th scans (-30.3%, p < 0.01). The figures for cortical-juxtacortical LV were also for 3-mm th scans (-16.2%, p < 0.01) and for 5-mm th scans (-26.7%, p < 0.01). We observed a significant correlation between T2-LV and GM atrophy in all slice thickness (r = -0.4 to -0.48, p = 0.001-0.003) and a modest relationship between cortical and cortical-juxtacortical LVs and disability, especially at 1.5-mm slice thickness (r = 0.35, p = 0.025). Use of thinner slices (1.5 mm) on 2D-FLAIR images can significantly increase the sensitivity and precision of detecting cortical and juxtracotical lesions in patients with MS. Cortical and juxtacortical lesions contribute more to disability development than total T2-LV alone.

Mitoxantrone treatment in patients with early relapsing-remitting multiple sclerosis

We investigated the clinical and MRI effects of mitoxantrone (MITOX) administered to 45 patients during the first five years of highly active relapsing-remitting multiple sclerosis. Differences occurring between the end of treatment and follow-up (clinical mean: 3.6 years; brain MR: 1.8 years) with respect to baseline variables (EDSS, annualized relapse rate, active T2 lesions, new T1 lesions and number of Gd-enhancing lesions) were analysed using parametric and non-parametric tests. One patient developed leukemia four months after the end of the treatment; no other serious adverse events occurred during treatment and the follow-up period. A clinically relevant reduction in the annualized relapse rate ( P < 0.0001 at end of treatment and P < 0.0001 at follow-up) and improvement in the EDSS ( P < 0.0001 at end of treatment and P = 0.0005 at follow-up) was found. At the end of treatment, 53% of patients experienced no increase in active T2 lesions, while 73% showed no increase in the number of new T1 lesions. At follow-up, 41 out of 45 (91%) patients showed a stable MRI pattern and were active-scan free. Despite potential serious adverse events, MITOX may be considered an option in selected patients with very active early MS. Multiple Sclerosis 2007; 13: 975—980. http://msj.sagepub.com

Time-series modeling of multiple sclerosis disease activity: a promising window on disease progression and repair potential?

This article discusses and reviews advanced forms of serial morphometry in the context of a disease progression model in multiple sclerosis (MS). This model of disease activity distinguishes between overall disease activity and the proportion thereof that becomes permanent damage. This translates into a progression model that features a repair potential, which, when exhausted, marks the conversion or progression from relapsing to progressive disease. The level of repair capacity at a given time determines the rate of progression. Both clinical and MRI variables appear to be in support of such a model. We examine possible MRI markers for this repair capacity, particularly the short-term behavior of new MRI lesions, quantified by methods of time-series analysis--that is, capturing lesion dynamics in the form of MRI intensity change directly, rather than shape or volume change. Lower rates of individual lesion recovery may represent lower repair and greater proximity to a progressive stage. Individuals with low transient lesion turnover appear to undergo more rapid progression and atrophy. Because disease-modifying therapies aim to alter the pathophysiological chain of inflammation, demyelination, and axonal loss, a therapeutic effect may therefore be more readily apparent as a change in lesion dynamics and recovery rate and level, rather than a change in total lesion burden or enhancing lesion number.

MRI to monitor treatment efficacy in multiple sclerosis

It is the primary goal of disease modifying treatments in multiple sclerosis (MS) to prevent the occurrence of new clinical deficits and lessen or prevent accumulation of disability. As a consequence, clinical aspects constitute the major outcome variables in treatment trials and are also the leading factor for treatment decisions in individual patients. However, determining treatment efficacy by clinical evaluation suffers from limited objectivity, sensitivity, and specificity for the underlying pathophysiologic aspects, which may constitute the target of a given therapy. Magnetic resonance imaging (MRI) can partly overcome these limitations by showing morphologic aspects of the disease with clinical relevance and responsiveness to therapy. Within the past 10 years sufficient data have been collected to establish the accumulation of new/enlarging T2 lesions and gadolinium enhancing lesions, T2 lesion load, T1-hypointense lesions, and brain volume changes as reasonably well-defined markers of disease processes, which may serve to monitor treatment efficacy. Accordingly, these variables have been extensively used for probing the efficacy of disease modifying treatments. In part they are also suited to guide therapeutic decisions in the individual patient. Further options may come from the use of advanced techniques like magnetization transfer MRI, diffusion-weighted MRI, and proton magnetic resonance spectroscopy, which detect more subtle MS related tissue abnormalities. Irrespective of the technique employed, great care has to be given to the standardization and reproducibility of both data acquisition and interpretation when using MRI to monitor treatment efficacy. For the individual patient therapeutic decisions based on MRI need experience and caution.

Conventional MRI in Multiple Sclerosis

During the past 10 years, conventional magnetic resonance imaging (cMRI) has become an established tool for the assessment of patients with multiple sclerosis (MS) and to monitor treatment trials. This is mainly due to the sensitivity and reproducibility of cMRI in the detection of MS-related damage. A large effort has also been devoted to develop imaging strategies capable of providing accurate estimates of the extent of disease-related damage not only in the brain, but also in the spinal cord and optic nerve. Guidelines have been defined to integrate MR findings in the diagnostic evaluation of patients at presentation with clinically isolated syndromes suggestive of MS, and specific acquisition protocols have been offered for monitoring longitudinal changes in patients with established disease. Despite the fact that the role of cMRI in MS has been profoundly obviated by the advent of modern and quantitative MR techniques, several issues are still unresolved. Technical development in acquisition and postprocessing, as well as the introduction of high-field magnets in the clinical arena, are likely to increase our understanding of disease pathobiology, mainly through an increased ability to quantify the extent of gray matter damage.

Statistical Issues Related to the Use of MRI Data in Multiple Sclerosis

Since magnetic resonance imaging (MRI) of the brain has proved to be the most important paraclinical tool for diagnosing multiple sclerosis (MS) and monitoring its evolution, methodological and statistical issues related to the use of MRI markers in MS have been the focus of several studies in the past 10 years. While many of these methodological issues have been addressed using standard procedures available from other areas of application of medical statistics, in some cases statistical procedures that are not standard have been developed specifically for MRI variables in MS. Two of the major achievements in the statistical methods applied to the use of MRI variables in MS in the past 10 years were the identification of a parametric model to describe the distribution of MRI lesion counts across patients and the study of the relationships between MRI markers and clinical variables, with the aim to validate MRI parameters as surrogates for clinical progression.

Long-term follow-up of patients treated with glatiramer acetate: a multicentre, multinational extension of the European/Canadian double-blind, placebo-controlled, MRI-monitored trial

Glatiramer acetate (GA) is effective in reducing clinical and magnetic resonance imaging (MRI) activity in relapsing-remitting multiple sclerosis (RRMS). Serial long-term MRI data are lacking for large cohorts of GA-treated patients. The European/Canadian GA study consisted of two consecutive phases, each lasting nine months. The first treatment phase was randomized, double-blind and placebo-controlled. The second was an open-label, active treatment phase with daily administration of 20 mg GA subcutaneously for all patients. For the long-term follow-up (LTFU), dual echo, pre- and postgadolinium T1-weighted brain MRI scans were obtained with the same acquisition scheme as for the original trial and a neurological assessment was performed. Lesion volumes, normalized brain volumes and percentage brain volume changes (PBVC) were measured. One hundred and forty-two (63.4%) of the 224 patients who completed the two phases of the European/Canadian study underwent the LTFU after a mean period of 5.8 years (range: 5.3-6.4); 73 were treated with GA from study initiation. MRI measures at LTFU did not significantly differ between patients originally assigned to placebo and those who were always treated with GA, but the proportion of patients who did not require walking aids at LTFU was lower in the latter group (P=0.034). PBVC between baseline and LTFU was significantly correlated with lesion load at study entry. An earlier initiation of GA treatment in patients with active RRMS might, at least partially, have a favourable impact on long-term disease evolution. Multiple Sclerosis 2007; 13: 502-508. http://msj.sagepub.com