Caudate nuclei volume, diffusion tensor metrics, and T(2) relaxation in healthy adults and relapsing-remitting multiple sclerosis patients: implications for understanding gray matter degeneration

PURPOSE

To investigate the utility of caudate nuclei (CN) macro- and microstructural metrics as markers of gray matter degeneration in healthy adults and relapsing-remitting multiple sclerosis (RRMS) patients.

MATERIALS AND METHODS

The normal age- and pathology-related changes in caudate nuclei volume (CNV), the corresponding diffusion tensor metrics, and the T(2) relaxation times were measured in a cohort of 32 healthy adults (12 men/20 women; age range 21-59 years) and 32 age-matched RRMS patients (8 men/34 women; age range 21-57 years).

RESULTS

Smaller values in both the absolute CNV and the caudate volume ratio relative to the total intracranial volume (CNVp) were observed in the RRMS group relative to healthy controls. The fractional anisotropy (FA), based on the diffusion tensor imaging (DTI) of the CN increased with age in healthy adults (r = 0.52; P = 0.003) but not in patients (r = 0.28; P = 0.12). The caudate FA value was approximately 9% larger in RRMS patients relative to controls (P = 0.001). The mean diffusivity of the CN was greater in the RRMS group compared to controls (P = 0.02). The caudate T(2) relaxation times were smaller in the RRMS group relative to the control group (3% reduction, P = 0.05). T(2) relaxation times did not exhibit age-related changes (P > 0.35) in either cohort. Strong and significant correlations between CNVp and whole-brain lesion load (r = -0.48; P = 0.005) and whole-brain CSF fraction (r = -0.46; P = 0.01) were also noted.

CONCLUSION

These preliminary findings indicate that caudate DTI-derived metrics can serve as potential quantitative radiological markers of MS pathology.

3D MPRAGE improves classification of cortical lesions in multiple sclerosis

BACKGROUND

Gray matter lesions are known to be common in multiple sclerosis (MS) and are suspected to play an important role in disease progression and clinical disability. A combination of magnetic resonance imaging (MRI) techniques, double-inversion recovery (DIR), and phase-sensitive inversion recovery (PSIR), has been used for detection and classification of cortical lesions. This study shows that high-resolution three-dimensional (3D) magnetization-prepared rapid acquisition with gradient echo (MPRAGE) improves the classification of cortical lesions by allowing more accurate anatomic localization of lesion morphology.

METHODS

11 patients with MS with previously identified cortical lesions were scanned using DIR, PSIR, and 3D MPRAGE. Lesions were identified on DIR and PSIR and classified as purely intracortical or mixed. MPRAGE images were then examined, and lesions were re-classified based on the new information.

RESULTS

The high signal-to-noise ratio, fine anatomic detail, and clear gray-white matter tissue contrast seen in the MPRAGE images provided superior delineation of lesion borders and surrounding gray-white matter junction, improving classification accuracy. 119 lesions were identified as either intracortical or mixed on DIR/PSIR. In 89 cases, MPRAGE confirmed the classification by DIR/PSIR. In 30 cases, MPRAGE overturned the original classification.

CONCLUSION

Improved classification of cortical lesions was realized by inclusion of high-spatial resolution 3D MPRAGE. This sequence provides unique detail on lesion morphology that is necessary for accurate classification.

Proton magnetic resonance spectroscopy in multiple sclerosis

Proton magnetic resonance spectroscopy ((1)H-MRS) provides tissue metabolic information in vivo. This article reviews the role of MRS-determined metabolic alterations in lesions, normal-appearing white matter, gray matter, and spinal cord in advancing our knowledge of pathologic changes in multiple sclerosis (MS). In addition, the role of MRS in objectively evaluating therapeutic efficacy is reviewed. This potential metabolic information makes MRS a unique tool to follow MS disease evolution, understand its pathogenesis, evaluate the disease severity, establish a prognosis, and objectively evaluate the efficacy of therapeutic interventions.

Deep gray matter atrophy in multiple sclerosis: a tensor based morphometry

Tensor based morphometry (TBM) was applied to determine the atrophy of deep gray matter (DGM) structures in 88 relapsing multiple sclerosis (MS) patients. For group analysis of atrophy, an unbiased atlas was constructed from 20 normal brains. The MS brain images were co-registered with the unbiased atlas using a symmetric inverse consistent nonlinear registration. These studies demonstrate significant atrophy of thalamus, caudate nucleus, and putamen even at a modest clinical disability, as assessed by the expanded disability status score (EDSS). A significant correlation between atrophy and EDSS was observed for different DGM structures: (thalamus: r=-0.51, p=3.85 x 10(-7); caudate nucleus: r=-0.43, p=2.35 x 10(-5); putamen: r=-0.36, p=6.12 x 10(-6)). Atrophy of these structures also correlated with 1) T2 hyperintense lesion volumes (thalamus: r=-0.56, p=9.96 x 10(-9); caudate nucleus: r=-0.31, p=3.10 x 10(-3); putamen: r=-0.50, p=6.06 x 10(-7)), 2) T1 hypointense lesion volumes (thalamus: r=-0.61, p=2.29 x 10(-10); caudate nucleus: r=-0.35, p=9.51 x 10(-4); putamen: r=-0.43, p=3.51 x 10(-5)), and 3) normalized CSF volume (thalamus: r=-0.66, p=3.55 x 10(-12); caudate nucleus: r=-0.52, p=2.31 x 10(-7), and putamen: r=-0.66, r=2.13 x 10(-12)). More severe atrophy was observed mainly in thalamus at higher EDSS. These studies appear to suggest a link between the white matter damage and DGM atrophy in MS.

Magnetic resonance imaging as a surrogate outcome for multiple sclerosis relapses

BACKGROUND

Magnetic resonance imaging (MRI) of lesions in the brain may be the best current candidate for a surrogate biological marker of clinical outcomes in relapsing remitting multiple sclerosis (MS), based on its role as an objective indicator of disease pathology. No biological surrogate marker has yet been validated for MS clinical outcomes.

OBJECTIVE

The objective of this study was to use a multi-phased study to determine if a valid surrogate relationship could be demonstrated between counts of contrast enhancing lesions (CELs) and occurrence of relapses in MS.

METHODS

We examined correlations for the concurrent and predictive relationship between CELs over 6 months and MS relapses over the same 6 months and an additional 6 months (total: 12 months), using available data on untreated patients from a large clinical trial and natural history database.

RESULTS

Concurrent and predictive correlations were inadequate to justify continuation of this study to the planned additional phases required to demonstrate a surrogate relationship between CELs and MS relapses.

CONCLUSIONS

Confidence intervals for correlations between CELs and MS relapses exclude the possibility that CELs can be a good surrogate for relapses over the time scales we investigated. Further exploration of surrogacy between MRI measures and MS clinical outcomes may require improved datasets, the development of MRI techniques that couple better to clinical disease, and the ability to test a wide range of imaging- and clinically-based hypotheses for surrogacy.

Diffusion-tensor MR imaging of cortical lesions in multiple sclerosis: initial findings

PURPOSE

To prospectively perform a direct measurement of fractional anisotropy (FA) and mean diffusivity (MD) in cortical lesions of patients with multiple sclerosis (MS).

MATERIALS AND METHODS

The study was approved by the institutional review board and was HIPAA compliant; informed consent was obtained. Magnetic resonance (MR) images, including double inversion-recovery (DIR), phase-sensitive inversion-recovery (PSIR), and diffusion-tensor images, were acquired from nine MS patients with cortical lesions (five women, four men; median age, 47 years) and nine age- and sex-matched volunteer control subjects. Following nonlinear elastically constrained image registration for aligning diffusion-weighted images to DIR images, maps of FA and MD were computed for each subject. Cortical lesions were identified on DIR images and validated by using PSIR images. The diffusion-tensor imaging maps were then overlaid on the coregistered DIR images, and mean FA and MD values were measured in regions of interest drawn on the cortical lesions. Differences between normal gray matter (GM) and cortical lesions were evaluated by using the generalized estimating equation. FA and MD histograms of whole brain and GM (global analysis) in healthy control subjects and MS patients were also computed for comparison with those in previously published studies.

RESULTS

FA and MD values were significantly higher in cortical lesions compared with similar regions in healthy control subjects. Histogram peak FA was significantly decreased and peak MD was significantly increased in patients relative to control subjects.

CONCLUSION

DIR and PSIR combined with nonlinear image registration allowed direct focal measurement of FA and MD in cortical lesions.

Cervical Spinal Cord Lesions in Multiple Sclerosis: T1-weighted Inversion-Recovery MR Imaging with Phase-Sensitive Reconstruction

This magnetic resonance (MR) imaging study was approved by the institutional review board and was HIPAA compliant. Written informed consent was obtained from all participants. The purpose of the study was to prospectively compare T1-weighted inversion recovery with short inversion time inversion recovery (STIR) and dual fast spin echo (FSE) for imaging cervical spinal cord lesions in patients with multiple sclerosis (MS). Twelve patients (eight men, four women; median age, 44 years) were imaged by using T1-weighted inversion recovery, STIR, and FSE. Contrast between lesions and normal cervical cord was measured for each sequence, and generalized estimating equation analysis was used to test statistical significance of the results. Normalized contrast between lesion and normal-appearing spinal cord was significantly higher for T1-weighted inversion recovery than for the other sequences (P < .0001). Use of phase-sensitive reconstruction improved lesion localization and boundary definition. These advantages of T1-weighted inversion recovery over STIR and dual-echo FSE suggest that it has potential in cervical spinal cord imaging of MS. (c) RSNA, 2007.

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.

Improved identification of intracortical lesions in multiple sclerosis with phase-sensitive inversion recovery in combination with fast double inversion recovery MR imaging

BACKGROUND AND PURPOSE

Accurate detection and classification of purely intracortical lesions in multiple sclerosis (MS) are important in understanding their role in disease progression and impact on the clinical manifestations of the disease. However, detection of these lesions with conventional MR imaging remains a challenge. Although double inversion recovery (DIR) has been shown to improve the sensitivity of the detection of cortical lesions, this sequence has low signal-to-noise ratio (SNR), poor delineation of lesion borders, and is prone to image artifacts. We demonstrate that intracortical lesions can be identified and classified with greater confidence by the combination of DIR with phase-sensitive inversion recovery (PSIR) images.

MATERIALS AND METHODS

A total of 16 subjects with MS were included in this study. DIR, PSIR, and fluid-attenuated inversion recovery (FLAIR) images were acquired and inspected by 3 experts, with identification of lesions by consensus. PSIR and DIR images were jointly used to classify lesions as purely intracortical, mixed gray-white matter, and juxtacortical. The difference in the number of lesions detected in each category was compared between combined PSIR and DIR and conventional FLAIR.

RESULTS

PSIR consistently allowed a clearer classification and delineation of lesions. Combined PSIR and DIR images showed a 337% improvement in the total number of lesions detected compared with FLAIR alone. Detection of intracortical lesions was improved by 417% compared with FLAIR. Detection of mixed gray-white matter and juxtacortical lesions was improved by 396% and 130%, respectively, compared with FLAIR.

CONCLUSION

Reliable detection and classification of intracortical lesions in MS are greatly improved by combined use of PSIR and DIR.

Longitudinal magnetic resonance spectroscopic imaging of primary progressive multiple sclerosis patients treated with glatiramer acetate: multicenter study

Multicenter proton magnetic resonance spectroscopic imaging (MRSI) studies were performed on 58 primary progressive multiple sclerosis (PPMS) patients from four centers for investigating the efficacy of glatiramer acetate (GA) treatment. These patients were drawn from 943 subjects who participated in the PROMiSe trial. In these MRSI studies, patients were followed over a period of 3 years. MRSI data were acquired by all the centers using the same pulse sequence, and spectral analysis was performed at a single site using a customized analysis software package. Quantitative metabolite ratios, N-acetyl aspartate (NAA)/creatine (Cr) and choline (Cho)/Cr, were compared between GA-treated and placebo-treated PPMS patients. There was no significant difference in metabolite ratios between GA-treated and placebo-treated patients. The difference in metabolite ratios between the normal-appearing tissues (NAT) and lesion-containing regions (LCR) in GA treated patients was not significantly different from placebo treated patients. Strong lipid resonances, even in the absence of lesions, were observed on MRSI data in both gray matter and white matter in placebo- and GA-treated PPMS patients. No significant difference in number of patients with lipids between the two groups over a period of 3 years was found.

Prognosis of the individual course of disease--steps in developing a decision support tool for Multiple Sclerosis

Background

Multiple sclerosis is a chronic disease of uncertain aetiology. Variations in its disease course make it difficult to impossible to accurately determine the prognosis of individual patients. The Sylvia Lawry Centre for Multiple Sclerosis Research (SLCMSR) developed an "online analytical processing (OLAP)" tool that takes advantage of extant clinical trials data and allows one to model the near term future course of this chronic disease for an individual patient.

Results

For a given patient the most similar patients of the SLCMSR database are intelligently selected by a model-based matching algorithm integrated into an OLAP-tool to enable real time, web-based statistical analyses. The underlying database (last update April 2005) contains 1,059 patients derived from 30 placebo arms of controlled clinical trials. Demographic information on the entire database and the portion selected for comparison are displayed. The result of the statistical comparison is provided as a display of the course of Expanded Disability Status Scale (EDSS) for individuals in the database with regions of probable progression over time, along with their mean relapse rate. Kaplan-Meier curves for time to sustained progression in the EDSS and time to requirement of constant assistance to walk (EDSS 6) are also displayed. The software-application OLAP anticipates the input MS patient's course on the basis of baseline values and the known course of disease for similar patients who have been followed in clinical trials.

Conclusion

This simulation could be useful for physicians, researchers and other professionals who counsel patients on therapeutic options. The application can be modified for studying the natural history of other chronic diseases, if and when similar datasets on which the OLAP operates exist.

Glatiramer acetate in primary progressive multiple sclerosis: results of a multinational, multicenter, double-blind, placebo-controlled trial

OBJECTIVE

To determine whether glatiramer acetate (GA) slows accumulation of disability in primary progressive multiple sclerosis.

METHODS

A total of 943 patients with primary progressive multiple sclerosis were randomized to GA or placebo (PBO) in this 3-year, double-blind trial. The primary end point was an intention-to-treat analysis of time to 1- (entry expanded disability status scale, 3.0-5.0) or 0.5-point expanded disability status scale change (entry expanded disability status scale, 5.5-6.5) sustained for 3 months. The trial was stopped after an interim analysis by an independent data safety monitoring board indicated no discernible treatment effect on the primary outcome. Intention-to-treat analyses of disability and magnetic resonance imaging end points were performed.

RESULTS

There was a nonsignificant delay in time to sustained accumulated disability in GA- versus PBO-treated patients (hazard ratio, 0.87 [95% confidence interval, 0.71-1.07]; p = 0.1753), with significant decreases in enhancing lesions in year 1 and smaller increases in T2 lesion volumes in years 2 and 3 versus PBO. Post hoc analysis showed that survival curves for GA-treated male patients diverged early from PBO-treated male subjects (hazard ratio, 0.71 [95% confidence interval, 0.53-0.95]; p = 0.0193).

INTERPRETATION

The trial failed to demonstrate a treatment effect of GA on primary progressive multiple sclerosis. Both the unanticipated low event rate and premature discontinuation of study medication decreased the power to detect a treatment effect. Post hoc analysis suggests GA may have slowed clinical progression in male patients who showed more rapid progression when untreated.

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

Segmentation of gadolinium-enhanced lesions on MRI in multiple sclerosis

PURPOSE

To develop and implement a method for identification and quantification of gadolinium (Gd) enhancements with minimal human intervention.

MATERIALS AND METHODS

Dual fast spin echo (FSE), fluid attenuation inversion recovery (FLAIR), and pre- and postcontrast T1-weighted spin echo were acquired on 22 subjects. The enhancements were identified on the postcontrast T1-weighted images based on morphological operations. A single threshold based on the ratio of the difference of postcontrast and precontrast T1 images with that of precontrast T1 images is applied to the reconstructed images to reduce the false classifications. False classification of enhancements arising from enhancing vasculature and structures such as the choroid plexus that lack a blood-brain barrier were reduced by assuming that the true enhancements are always associated with hyperintense lesions on T2-weighted images (T2 lesions). The enhanced lesions were further delineated based on fuzzy connectivity.

RESULTS

The segmented Gd enhancements were evaluated quantitatively with manually identified enhancements based on similarity measures. The average similarity index (SI) of 0.76 suggests excellent performance of the proposed methodology. The Bland-Altman plot shows a close agreement between the results obtained manually and those based on the proposed methodology.

CONCLUSION

The proposed algorithm identifies and quantifies Gd enhancements accurately with minimal human intervention.

EFNS guidelines on the use of neuroimaging in the management of multiple sclerosis

Magnetic resonance (MR)-based techniques are widely used for the assessment of patients with suspected and definite multiple sclerosis (MS). However, despite the publication of several position papers, which attempted to define the utility of MR techniques in the management of MS, their application in everyday clinical practice is still suboptimal. This is probably related, not only, to the fact that the majority of published guidelines focused on the optimization of MR technology in clinical trials, but also to the continuing development of modern, quantitative MR-based techniques, that have not as yet entered the clinical arena. The present report summarizes the conclusions of the 'EFNS Expert Panel of Neuroimaging of MS' on the application of conventional and non-conventional MR techniques to the clinical management of patients with MS. These guidelines are intended to assist in the use of conventional MRI for the diagnosis and longitudinal monitoring of patients with MS. In addition, they should provide a foundation for the development of more widespread but rational clinical applications of non-conventional MR-based techniques in studies of MS patients.

MRI T2 lesion burden in multiple sclerosis: a plateauing relationship with clinical disability

BACKGROUND

Previous studies have shown only modest correlation between multiple sclerosis (MS) lesions on MRI and clinical disability.

OBJECTIVE

To investigate the relationship between proton density/T2-weighted (T2) burden of disease (BOD) quantitatively measured on MRI scans and clinical determinants including disability.

METHODS

Using the Sylvia Lawry Centre for Multiple Sclerosis Research (SLCMSR) database, the authors studied baseline T2 BOD data from a pooled subsample of 1,312 placebo MS patients from 11 randomized controlled trials. Univariate comparisons guided development of multiple regression models incorporating the most important clinical predictors.

RESULTS

Significant, although weak to moderate, correlations were found between T2 BOD and age at disease onset, disease duration, disease course, disability (as measured by the Expanded Disability Status Scale [EDSS]), relapse rate, certain presenting symptoms, and gadolinium enhancement. An unexpected but key finding that persisted in the multiple regression analyses was a plateauing relationship between T2 BOD and disability for EDSS values above 4.5.

CONCLUSIONS

This study confirmed the limited correlation between clinical manifestations and T2 burden of disease (BOD) but revealed an important plateauing relationship between T2 BOD and disability.

Unified approach for multiple sclerosis lesion segmentation on brain MRI

The presence of large number of false lesion classification on segmented brain MR images is a major problem in the accurate determination of lesion volumes in multiple sclerosis (MS) brains. In order to minimize the false lesion classifications, a strategy that combines parametric and nonparametric techniques is developed and implemented. This approach uses the information from the proton density (PD)- and T2-weighted and fluid attenuation inversion recovery (FLAIR) images. This strategy involves CSF and lesion classification using the Parzen window classifier. Image processing, morphological operations, and ratio maps of PD- and T2-weighted images are used for minimizing false positives. Contextual information is exploited for minimizing the false negative lesion classifications using hidden Markov random field-expectation maximization (HMRF-EM) algorithm. Lesions are delineated using fuzzy connectivity. The performance of this algorithm is quantitatively evaluated on 23 MS patients. Similarity index, percentages of over, under, and correct estimations of lesions are computed by spatially comparing the results of present procedure with expert manual segmentation. The automated processing scheme detected 80% of the manually segmented lesions in the case of low lesion load and 93% of the lesions in those cases with high lesion load.

Effects of oral glatiramer acetate on clinical and MRI-monitored disease activity in patients with relapsing multiple sclerosis: a multicentre, double-blind, randomised, placebo-controlled study

BACKGROUND

Parenterally administered glatiramer acetate reduces the frequency of relapses and the formation of active brain lesions seen with MRI in multiple sclerosis. This study assessed whether two doses of glatiramer acetate given orally could improve clinical and MRI measures of inflammation and neurodegeneration in a large cohort of patients with relapsing-remitting multiple sclerosis.

METHODS

1912 patients with relapsing-remitting multiple sclerosis were screened and 1651 were randomised to receive 50 mg or 5 mg of glatiramer acetate or placebo by daily oral administration over 14 months. The intention-to-treat cohort consisted of 1644 patients who took at least one dose of study medication (50 mg glatiramer acetate [n=543], 5 mg glatiramer acetate [n=553], placebo [n=548]). After baseline investigation, clinical assessments were done every 2 months and MRI was obtained for all patients at baseline and at study exit. Additionally, MRI was undertaken every 2 months for a cohort of 486 patients. The primary outcome was the total number of confirmed relapses observed during the study period. Several prespecified clinical and MRI secondary and tertiary outcomes assessed treatment efficacy on inflammation and neurodegeneration due to multiple sclerosis.

FINDINGS

The cumulative number of confirmed relapses did not differ between the two active treatment groups and the placebo group. Relative to placebo, the rate ratio for the 50 mg glatiramer acetate treated group was 0.92 (95% CI 0.77-1.08, p=0.30) and for the 5 mg glatiramer acetate treated group was 0.98 (0.83-1.15, p=0.76). No drug effect was seen for any of the secondary and tertiary endpoints. The study drug was safe and well tolerated.

INTERPRETATION

5 mg and 50 mg glatiramer acetate administered orally on a daily basis do not affect relapse rate or other clinical and MRI parameters of disease activity and burden in patients with relapsing-remitting multiple sclerosis. Treatment with oral formulations of glatiramer acetate at the doses tested cannot be recommended.

The use of glatiramer acetate in the treatment of multiple sclerosis

Glatiramer acetate is a collection of synthetic polypeptides indicated as therapy for relapsing a remitting multiple sclerosis (MS). Current understanding of the immunological and neuroprotective mechanisms of action of GA makes it unique among current MS therapies. The clinical efficacy of GA appears similar to that of the recombinant beta interferons. GA has a favorable side effect profile with excellent patient compliance and long-term acceptance. The results of pivotal controlled clinical trials and long-term data derived from organized extension studies are reviewed. Supportive data from open-label comparison, combination treatment and therapeutic switch studies are also provided to enable informed decisions on the appropriate place for GA among other immunomodulatory treatments for relapsing MS.

Diagnostic criteria for multiple sclerosis: 2005 revisions to the "McDonald Criteria"

New diagnostic criteria for multiple sclerosis integrating magnetic resonance image assessment with clinical and other paraclinical methods were introduced in 2001. The "McDonald Criteria" have been extensively assessed and used since 2001. New evidence and consensus now strengthen the role of these criteria in the multiple sclerosis diagnostic workup to demonstrate dissemination of lesions in time, to clarify the use of spinal cord lesions, and to simplify diagnosis of primary progressive disease. The 2005 Revisions to the McDonald Diagnostic Criteria for MS should simplify and speed diagnosis, whereas maintaining adequate sensitivity and specificity.

Pilot study to examine the effect of antibiotic therapy on MRI outcomes in RRMS

This trial examined the safety and possible MRI and clinical effects of anti-chlamydial antibiotic therapy in relapsing-remitting MS (RRMS). Newly diagnosed MS patients were selected to participate if they showed Chlamydia pneumoniae gene in their CSF and had one or more enhancing lesions on brain magnetic resonance imaging (MRI). After a 4-month run in phase of monthly MRI, patients were randomized to receive rifampin (300 mg twice daily) and azithromycin (500 mg every other day) for 6 months or placebo (PBO). Patients then had monthly MRI on therapy and two additional scans on months 12 and 14. Lumbar punctures were repeated between months 7 and 8 and within 2 weeks of termination of the study. Data on 4 patients on treatment and 4 on PBO were available for analysis. The primary outcome measure of showing a beneficial effect on enhancing lesions was not met. However, there was a significant difference in brain parenchymal fraction loss favoring those patient receiving antibiotics compared with PBO (p< or =0.02). Three of the four patients on antibiotic therapy cleared the organism from the CSF by month 12; in the PBO group one patient cleared the organism. The reduction in atrophy in patients receiving antibiotics must be viewed with caution, due to the small number of patients studied.

Segmentation and quantification of black holes in multiple sclerosis

A technique that involves minimal operator intervention was developed and implemented for identification and quantification of black holes on T1-weighted magnetic resonance images (T1 images) in multiple sclerosis (MS). Black holes were segmented on T1 images based on grayscale morphological operations. False classification of black holes was minimized by masking the segmented images with images obtained from the orthogonalization of T2-weighted and T1 images. Enhancing lesion voxels on postcontrast images were automatically identified and eliminated from being included in the black hole volume. Fuzzy connectivity was used for the delineation of black holes. The performance of this algorithm was quantitatively evaluated on 14 MS patients.

Phase-sensitive T1 inversion recovery imaging: a time-efficient interleaved technique for improved tissue contrast in neuroimaging

BACKGROUND AND PURPOSE

High tissue contrast and short acquisition time are desirable when scanning patients. The purpose of this report is to describe the implementation of a new technique for generating high gray matter (GM) and white matter (WM) contrast in a short scan time, make a quantitative evaluation of the contrast efficiency, and explore its potential applications in neuroimaging.

METHOD

A fully interleaved T1-weighted inversion recovery (T1IR) sequence with phase-sensitive reconstruction (PS-T1IR) is implemented. This sequence is compared with conventional T1-weighted spin-echo imaging (T1SE) and T1-weighted fluid-attenuated inversion recovery (T1FLAIR). The time efficiency and contrast enhancement have been quantitatively analyzed in normal volunteers. The performance of the sequence is evaluated in >30 patients with neurologic disorders. The sensitivity of PS-T1IR relative to T1SE in detecting gadolinium enhancements is also evaluated.

RESULTS

PS-T1IR is more time-efficient than T1SE and generates better GM-WM contrast. It results in the best contrast-to-noise ratio (CNR) efficiency (1.16) compared with T1FLAIR (0.73) and T1SE (0.23). For a typical clinical protocol, PS-T1IR takes only 1:30 minutes versus 2:40 minutes for T1SE imaging for the whole brain coverage. Although gadolinium enhancements are detected with comparable sensitivity on both PS-T1IR and T1SE sequences, in certain instances, the latter sequence appears to be more sensitive in demonstrating gadolinium enhancements within WM.

CONCLUSION

PS-T1IR has the highest CNR efficiency compared with T1FLAIR and T1SE. It is a very practical technique for neuroradiologic applications.

Imaging of multiple sclerosis: role in neurotherapeutics

Magnetic resonance imaging (MRI) plays an ever-expanding role in the evaluation of multiple sclerosis (MS). This includes its sensitivity for the diagnosis of the disease and its role in identifying patients at high risk for conversion to MS after a first presentation with selected clinically isolated syndromes. In addition, MRI is a key tool in providing primary therapeutic outcome measures for phase I/II trials and secondary outcome measures in phase III trials. The utility of MRI stems from its sensitivity to longitudinal changes including those in overt lesions and, with advanced MRI techniques, in areas affected by diffuse occult disease (the so-called normal-appearing brain tissue). However, all current MRI methodology suffers from limited specificity for the underlying histopathology. Conventional MRI techniques, including lesion detection and measurement of atrophy from T1- or T2-weighted images, have been the mainstay for monitoring disease activity in clinical trials, in which the use of gadolinium with T1-weighted images adds additional sensitivity and specificity for areas of acute inflammation. Advanced imaging methods including magnetization transfer, fluid attenuated inversion recovery, diffusion, magnetic resonance spectroscopy, functional MRI, and nuclear imaging techniques have added to our understanding of the pathogenesis of MS and may provide methods to monitor therapies more sensitively in the future. However, these advanced methods are limited by their cost, availability, complexity, and lack of validation. In this article, we review the role of conventional and advanced imaging techniques with an emphasis on neurotherapeutics.