Identification of a predominant cognitive phenotype in patients with multiple sclerosis

BACKGROUND AND PURPOSE

Cognitive impairment occurs frequently in multiple sclerosis (MS). However, the prevalence and clinical characteristics of cognitive MS phenotype are not well established. The aim of the study was to characterize the clinical course and neurocognitive impairment of patients with MS meeting an Expanded Disability Status Scale (EDSS)-defined cognitive phenotype.

METHODS

A total of 2302 patients from the Comprehensive Longitudinal Investigation of Multiple Sclerosis at Brigham and Women's Hospital (CLIMB) study were studied. Predominant cognitive MS phenotype was defined as EDSS Cerebral Functional System (FS) subscore ≥3 and remaining EDSS FS subscores ≤2 on at least one clinical visit. Demographic/clinical characteristics, phenotype stability and neurocognitive domain impairment of these subjects were assessed.

RESULTS

A total of 60 of 2302 (2.6%) patients (age 52.8 ± 10.8 years, 68% female, 82% relapsing MS) met criteria for phenotype designation. A total of 29 of 60 (48%) were designated within 10 years of their presenting MS symptom. The mean cohort annualized relapse rate was 0.38 and EDSS score at last clinical assessment was 3.2 ± 1.3. Cognitive phenotype status was poorly sustained, with only 27% of subjects maintaining Cerebral FS score ≥2 throughout all follow-up. However, predominant cognitive phenotype subjects with clinical neuropsychiatric testing [n = 39/60 (65%)] frequently had cognitive impairment (1.5 SD below mean) in ≥1 domain [n = 30/39 (77%) of subjects] affecting memory, attention/executive function and processing speed. A total of 11 of 39 (28%) patients had severe-range cognitive impairment (3.0 SD below mean). Cognitive phenotype designation was associated with low rate of employment at last clinical assessment.

CONCLUSION

Predominant cognitive MS phenotype is rare, although an EDSS-based definition identifies patients with multidomain cognitive impairment and may serve as a practical screen for identification of patients who might warrant close monitoring of neurocognitive status.

Predictors of hematological abnormalities in multiple sclerosis patients treated with fingolimod and dimethyl fumarate and impact of treatment switch on lymphocyte and leukocyte count

BACKGROUND

There is limited data regarding the predictors of hematological abnormalities in multiple sclerosis (MS) patients treated with dimethyl fumarate (DMF) or fingolimod (FNG), and the impact of treatment switch on lymphocyte and leukocyte count METHODS: We identified 405 patients on DMF and 300 patients on FNG (treatment duration: at least 12 month) within a large prospective study of MS patients conducted at the Partners MS Center, Brigham and Women's Hospital (CLIMB study) between Jan 2011 to Feb 2016. Patients had complete blood counts with differentials at baseline and every 6 months while on treatment. Most participants had a clinical visit with complete neurologic examinations every 6 months and brain MRI scan every 12 months. T cell subset profile was available for subgroup of patients (n = 116).

RESULTS

In the FNG group, the risk of developing lymphopenia grade 4 (< 200) was higher in female patients (p = 0.0117) and those who were previously treated with natalizumab (p = 0.0116), while the risk of lymphopenia grade 3b+4 (< 350) was higher in female patients (p = 0.0009). DMF treated patients with lower baseline lymphocyte count had a higher chance of developing lymphopenia grade 2 (< 800) (p < 0.0001) or 2+3 (< 500) (p < 0.0001). We examined the effect of treatment switch between DMF and FNG. No significant recovery in lymphocyte and leukocyte count was observed after treatment switches. Reduced dosing of FNG in patients with lymphopenia led to increase in lymphocyte count but also increased disease activity in 25% of patients.

CONCLUSION

Female sex and prior exposure to natalizumab increased the probability of lymphopenia on FNG, while low absolute lymphocyte count was associated with increased risk of lymphopenia on DMF. Parallel switch did not lead to recovery from hematological abnormalities. Long-term studies with larger number of patients are required to confirm our findings and to establish guidelines for prediction and management of hematological abnormalities.

Patients report worse MS symptoms after menopause: findings from an online cohort

BACKGROUND

Many women with multiple sclerosis (MS) are postmenopausal, yet the impact of menopause on MS symptoms is unknown.

OBJECTIVE

To investigate patient-reported impact of menopause in a large online research platform, PatientsLikeMe (PLM).

METHODS

A detailed reproductive history survey was deployed to PLM members, and responses were linked to PLM׳s prospectively collected patient-reported severity score (MS Rating Scale, MSRS). The MSRS has previously shown good correlation with physician-derived EDSS scores.

RESULTS

Of the 513 respondents, 55% were postmenopausal; 54% of these reported induced menopause. Median age at natural menopause was 51. Surgical menopause occurred at an earlier age (p<0.001) and was associated with more hormone replacement therapy use (p=0.02) than natural menopause. Postmenopausal status, surgical menopause, and earlier age at menopause were all associated with worse MSRS scores (p≤0.01) in regressions adjusting for age, disease type and duration.

CONCLUSION

Postmenopausal patients in this study reported worse MS disease severity. Further, this study highlights a utility for online research platforms, which allow for rapid generation of hypotheses that then require validation in clinical settings.

Low testosterone is associated with disability in men with multiple sclerosis

BACKGROUND

Gonadal steroids may modulate disease course in multiple sclerosis (MS).

OBJECTIVE

To assess the prevalence and clinical associations of hypogonadism in men with MS.

METHODS

Male patients, aged 18-65 years, with relapsing-remitting MS (RRMS) or clinically-isolated syndrome (CIS) and their first symptom < 10 years prior were selected from a longitudinal clinical study. We measured their hormones in stored morning blood samples, and collected their Expanded Disability Status Scale (EDSS) scores every 6 months and their Symbol Digit Modalities Test (SDMT) results annually.

RESULTS

Our analysis included 96 men with a mean age of 40 years, EDSS of 1.1 and disease duration of 4.6 years. Of these men, 39% were hypogonadal (total testosterone < 288 ng/dL); none showed compensatory elevations in luteinizing hormone. Their low testosterone levels and testosterone:estradiol ratios were negatively correlated with body mass index (BMI) and leptin, and showed no correlation with 25-hydroxy-vitamin D levels. In our primary cross-sectional analyses, there was a negative age-adjusted correlation between total testosterone and EDSS (p = 0.044). In the age-adjusted longitudinal analyses, higher baseline testosterone levels were associated with less decline in SDMT (p = 0.012).

CONCLUSIONS

Men with MS may experience hypogonadotropic hypogonadism. Low testosterone levels may be associated with worse clinical outcomes. A potential neuroprotective role for testosterone warrants further investigation.

Metabolic and endocrine correlates of cognitive function in healthy young women

OBJECTIVE

Obesity has been associated with cognitive decline in longitudinal studies of older individuals. We hypothesized that the cognitive sequelae of obesity may be detectable in the reproductive years. In addition, we explored the hypothesis that these associations may be mediated by the hormonal milieu.

DESIGN AND METHODS

Of 49 young healthy lean and overweight women aged 20-45, we investigated the association between performance on a battery of cognitive tests, body composition parameters [body mass index, total fat, abdominal (visceral, subcutaneous, and total) adipose tissue, and muscle], and hormone levels (insulin, adiponectin, leptin, insulin-like growth factor 1 (IGF-1), estrogen, testosterone, and vitamin D).

RESULTS

We found a significant negative association between both visceral adiposity and muscle, and performance in the domain of verbal learning and memory, after controlling for age and education. Other body composition parameters showed similar trends (0.05 < P < 0.10). Additionally, the degree of insulin resistance was negatively associated with executive function domain. None of the associations between the other hormones examined (adipokines, IGF-1, gonadal hormones, and vitamin D) and cognitive function were significant.

CONCLUSION

These preliminary findings suggest a possible association between obesity and cognitive function in healthy young women of reproductive age. More research is warranted into the potential modulatory effect of insulin resistance on this association.

Diffusion tensor analysis of pediatric multiple sclerosis and clinically isolated syndromes

BACKGROUND AND PURPOSE

DTI has shown focal and diffuse white matter abnormalities in adults and children with MS. Here we explore whether DTI abnormalities are present at the time of a first attack or CIS in children and whether early DTI features can predict the development of MS.

MATERIALS AND METHODS

We assessed region-of-interest and tract-based mean ADC and mean FA values for 3 major white matter pathways and NAWM in 20 children with MS, 27 children with forms of CIS, and controls. Tracts were selected by using standard region-of-interest placements on color FA maps. Identical ROIs were placed in the NAWM on b = 0 T2-weighted images to ensure that both ROIs and resulting tracts passed through NAWM. Conventional MR imaging characteristics were assessed by visual inspection. Statistical analysis compared FA and ADC values between groups by a t test. Logistic regression assessed the predictive value of DTI measures and published conventional MR imaging measures for conversion from CIS to MS.

RESULTS

In pediatric patients with MS, all white matter pathways and analysis confined to the NAWM demonstrated higher mean ADC values and lower mean FA than in controls. In contrast, there were no significant differences in mean ADC and mean FA of white matter pathways in all CIS cohorts compared with controls. In the CIS cohort, none of the DTI measures in white matter pathways or in NAWM were significantly associated with conversion to RRMS in univariate or multivariate models (P > .05 in all models).

CONCLUSIONS

There are significant anisotropic abnormalities in the NAWM of major tracts in children with MS. In contrast, there were no significant changes in pediatric patients with CIS compared with controls at baseline. DTI measures did not predict conversion to MS. The period between CIS and conversion to pediatric MS may represent a window of opportunity for the prevention of diffuse damage in the CNS and potentially progressive disability.

Mechanically adaptive intracortical implants improve the proximity of neuronal cell bodies

The hypothesis is that the mechanical mismatch between brain tissue and microelectrodes influences the inflammatory response. Our unique, mechanically adaptive polymer nanocomposite enabled this study within the cerebral cortex of rats. The initial tensile storage modulus of 5 GPa decreases to 12 MPa within 15 min under physiological conditions. The response to the nanocomposite was compared to surface-matched, stiffer implants of traditional wires (411 GPa) coated with the identical polymer substrate and implanted on the contralateral side. Both implants were tethered. Fluorescent immunohistochemistry labeling examined neurons, intermediate filaments, macrophages, microglia and proteoglycans. We demonstrate, for the first time, a system that decouples the mechanical and surface chemistry components of the neural response. The neuronal nuclei density within 100 µm of the device at four weeks post-implantation was greater for the compliant nanocomposite compared to the stiff wire. At eight weeks post-implantation, the neuronal nuclei density around the nanocomposite was maintained, but the density around the wire recovered to match that of the nanocomposite. The glial scar response to the compliant nanocomposite was less vigorous than it was to the stiffer wire. The results suggest that mechanically associated factors such as proteoglycans and intermediate filaments are important modulators of the response of the compliant nanocomposite.

A 3T MR imaging investigation of the topography of whole spinal cord atrophy in multiple sclerosis

BACKGROUND AND PURPOSE

Spinal cord atrophy is a common feature of MS. However, it is unknown which cord levels are most susceptible to atrophy. We performed whole cord imaging to identify the levels most susceptible to atrophy in patients with MS versus controls and also tested for differences among MS clinical phenotypes.

MATERIALS AND METHODS

Thirty-five patients with MS (2 with CIS, 27 with RRMS, 2 with SPMS, and 4 with PPMS phenotypes) and 27 healthy controls underwent whole cord 3T MR imaging. The spinal cord contour was segmented and assigned to bins representing each C1 to T12 vertebral level. Volumes were normalized, and group comparisons were age-adjusted.

RESULTS

There was a trend toward decreased spinal cord volume at the upper cervical levels in PPMS/SPMS versus controls. A trend toward increased spinal cord volume throughout the cervical and thoracic cord in RRMS/CIS versus controls reached statistical significance at the T10 vertebral level. A statistically significant decrease was found in spinal cord volume at the upper cervical levels in PPMS/SPMS versus RRMS/CIS.

CONCLUSIONS

Opposing pathologic factors impact spinal cord volume measures in MS. Patients with PPMS demonstrated a trend toward upper cervical cord atrophy. However patients with RRMS showed a trend toward increased volume at the cervical and thoracic levels, which most likely reflects inflammation or edema-related cord expansion. With the disease causing both expansion and contraction of the cord, the specificity of spinal cord volume measures for neuroprotective therapeutic effect may be limited.

Identification and clinical impact of multiple sclerosis cortical lesions as assessed by routine 3T MR imaging

BACKGROUND AND PURPOSE

Histopathologic studies have reported widespread cortical lesions in MS; however, in vivo detection by using routinely available pulse sequences is challenging. We investigated the relative frequency and subtypes of cortical lesions and their relationships to white matter lesions and cognitive and physical disability.

MATERIALS AND METHODS

Cortical lesions were identified and classified on the basis of concurrent review of 3D FLAIR and 3D T1-weighted IR-SPGR 3T MR images in 26 patients with MS. Twenty-five patients completed the MACFIMS battery. White matter lesion volume, cortical lesion number, and cortical lesion volume were assessed.

RESULTS

Overall, 249 cortical lesions were detected. Cortical lesions were present in 24/26 patients (92.3%) (range per patient, 0-30; mean, 9.6 ± 8.8). Most (94.4%, n = 235) cortical lesions were classified as mixed cortical-subcortical (type I); the remaining 5.6% (n = 14) were classified as purely intracortical (type II). Subpial cortical lesions (type III) were not detected. White matter lesion volume correlated with cortical lesion number and cortical lesion volume (r(S) = 0.652, r(S) = 0.705, respectively; both P < .001). After controlling for age, depression, and premorbid intelligence, we found that all MR imaging variables (cortical lesion number, cortical lesion volume, white matter lesion volume) correlated with the SDMT score (R(2) = 0.513, R(2) = 0.449, R(2) = 0.418, respectively; P < .014); cortical lesion number also correlated with the CVLT-II scores (R(2) = 0.542-0.461, P < .043). The EDSS scores correlated with cortical lesion number and cortical lesion volume (r(S) = 0.472, r(S) = 0.404, respectively; P < .05), but not with white matter lesion volume.

CONCLUSIONS

Our routinely available imaging method detected many cortical lesions in patients with MS and was useful in their precise topographic characterization in the context of the gray matter-white matter junction. Routinely detectable cortical lesions were related to physical disability and cognitive impairment.

HLA B*44: protective effects in MS susceptibility and MRI outcome measures

OBJECTIVE

In addition to the main multiple sclerosis (MS) major histocompatibility complex (MHC) risk allele (HLA DRB1*1501), investigations of the MHC have implicated several class I MHC loci (HLA A, HLA B, and HLA C) as potential independent MS susceptibility loci. Here, we evaluate the role of 3 putative protective alleles in MS: HLA A*02, HLA B*44, and HLA C*05.

METHODS

Subjects include a clinic-based patient sample with a diagnosis of either MS or a clinically isolated syndrome (n = 532), compared to subjects in a bone marrow donor registry (n = 776). All subjects have 2-digit HLA data. Logistic regression was used to determine the independence of each allele's effect. We used linear regression and an additive model to test for correlation between an allele and MRI and clinical measures of disease course.

RESULTS

After accounting for the effect of HLA DRB1*1501, both HLA A*02 and HLA B*44 are validated as susceptibility alleles (p(A*02) 0.00039 and p(B*44) 0.00092) and remain significantly associated with MS susceptibility in the presence of the other allele. Although A*02 is not associated with MS outcome measures, HLA B*44 demonstrates association with a better radiologic outcome both in terms of brain parenchymal fraction and T2 hyperintense lesion volume (p = 0.03 for each outcome).

CONCLUSION

The MHC class I alleles HLA A*02 and HLA B*44 independently reduce susceptibility to MS, but only HLA B*44 appears to influence disease course, preserving brain volume and reducing the burden of T2 hyperintense lesions in subjects with MS.

Analysis of 55 autoimmune disease and type II diabetes loci: further confirmation of chromosomes 4q27, 12q13.2 and 12q24.13 as type I diabetes loci, and support for a new locus, 12q13.3-q14.1

A candidate gene study was conducted on 10 established type II diabetes genes and 45 genes associated with autoimmune diseases, including type I diabetes (T1D), in a maximum of 1410 affected sib-pair families assembled by the Type I Diabetes Genetics Consortium. Associations at P values <10(-3) were found for three known T1D regions at chromosomes 4q27, 12q13.2 and 12q24.13 (http://www.T1DBase.org). Support was obtained for a newly identified T1D candidate locus on chromosome 12q13.3-12q14.1 (rs1678536/KIF5A: P=8.1 x 10(-3); relative risk (RR) for minor allele=0.89, 95% CI=0.82-0.97), which has a separate association from the previously reported T1D candidate locus ERBB3/12q13.2-q13.3. Our new evidence adds to that previously published for the same gene region in a T1D case-control study (rs1678542; P=3.0 x 10(-4); odds ratio (OR)=0.92, 95% CI=0.88-0.96). This region, which contains many genes, has also been associated with rheumatoid arthritis.

Tract-based analysis of callosal, projection, and association pathways in pediatric patients with multiple sclerosis: a preliminary study

BACKGROUND AND PURPOSE

Region-of-interest (ROI) and tract-based diffusion tensor imaging (DTI) analyses have detected increased apparent diffusion coefficients (ADCs) and decreased fractional anisotropy (FA) in callosal and projection systems of adult patients with multiple sclerosis (MS). We explored whether similar changes occur in pediatric patients with MS, assessing 3 major white matter pathways (interhemispheric, projection, and intrahemispheric) in both visibly involved and normal-appearing white matter (NAWM).

MATERIALS AND METHODS

DTI datasets from 10 patients with established pediatric MS and 10 age- sex-, and imaging technique-matched controls were analyzed. Tracts were reconstructed by using a fiber assignment by continuous tracking algorithm with a diffusion-weighted imaging mask and a 35 degrees angular threshold. Tracts were selected by using standard ROI placements on color FA maps cross-referenced to b = 0 T2-weighted images for studying white matter pathways. Ten identical ROIs were placed in NAWM on b = 0 T2-weighted images to ensure that both ROIs and resulting tracts passed through NAWM.

RESULTS

In pediatric MS, all tracts had higher mean ADC values (P = .002 to P < .04) and lower mean FA (P = .009 to P < .02) than those in healthy controls. Even when the tracts were confined to NAWM, the mean ADC was higher (P < .004 to P < .05) and the mean FA was lower (P = .002 to P < .02). T2 lesion burden correlated with tract-based mean ADC. ROI mean ADC increased, and both tract and ROI mean FA decreased with increasing T2 lesion burden, however with a statistically nonsignificant correlation.

CONCLUSIONS

Increased mean ADC and decreased mean FA occur in all 3 major white matter pathways, both in visibly involved white matter and NAWM in pediatric MS.

Regional white matter atrophy--based classification of multiple sclerosis in cross-sectional and longitudinal data

BACKGROUND AND PURPOSE

The different clinical subtypes of multiple sclerosis (MS) may reflect underlying differences in affected neuroanatomic regions. Our aim was to analyze the effectiveness of jointly using the inferior subolivary medulla oblongata volume (MOV) and the cross-sectional area of the corpus callosum in distinguishing patients with relapsing-remitting multiple sclerosis (RRMS), secondary-progressive multiple sclerosis (SPMS), and primary-progressive multiple sclerosis (PPMS).

MATERIALS AND METHODS

We analyzed a cross-sectional dataset of 64 patients (30 RRMS, 14 SPMS, 20 PPMS) and a separate longitudinal dataset of 25 patients (114 MR imaging examinations). Twelve patients in the longitudinal dataset had converted from RRMS to SPMS. For all images, the MOV and corpus callosum were delineated manually and the corpus callosum was parcellated into 5 segments. Patients from the cross-sectional dataset were classified as RRMS, SPMS, or PPMS by using a decision tree algorithm with the following input features: brain parenchymal fraction, age, disease duration, MOV, total corpus callosum area and areas of 5 segments of the corpus callosum. To test the robustness of the classification technique, we applied the results derived from the cross-sectional analysis to the longitudinal dataset.

RESULTS

MOV and central corpus callosum segment area were the 2 features retained by the decision tree. Patients with MOV >0.94 cm(3) were classified as having RRMS. Patients with progressive MS were further subclassified as having SPMS if the central corpus callosum segment area was <55.12 mm(2), and as having PPMS otherwise. In the cross-sectional dataset, 51/64 (80%) patients were correctly classified. For the longitudinal dataset, 88/114 (77%) patient time points were correctly classified as RRMS or SPMS.

CONCLUSIONS

Classification techniques revealed differences in affected neuroanatomic regions in subtypes of multiple sclerosis. The combination of central corpus callosum segment area and MOV provides good discrimination among patients with RRMS, SPMS, and PPMS.

Spinal cord lesions and clinical status in multiple sclerosis: A 1.5 T and 3 T MRI study

OBJECTIVE

Assess the relationship between spinal cord T2 hyperintense lesions and clinical status in multiple sclerosis (MS) with 1.5 and 3 T MRI.

METHODS

Whole cord T2-weighted fast spin-echo MRI was performed in 32 MS patients [Expanded Disability Status Scale (EDSS) score (mean+/-SD: 2+/-1.9), range 0-6.5]. Protocols at 1.5 T and 3 T were optimized and matched on voxel size.

RESULTS

Moderate correlations were found between whole cord lesion volume and EDSS score at 1.5 T (r(s)=.36, p=0.04), but not at 3 T (r(s)=0.13, p=0.46). Pyramidal Functional System Score (FSS) correlated with thoracic T2 lesion number (r(s)=.46, p=0.01) and total spinal cord lesion number (r(s)=0.37, p=0.04) and volume (r(s)=0.37, p=0.04) at 1.5 T. Bowel/bladder FSS correlated with T2 lesion volume and number in the cervical, thoracic, and total spine at 1.5 T (r(s) 0.40-0.57, all p<0.05). These MRI-FSS correlations were non-significant at 3 T. However, these correlation coefficients did not differ significantly between platforms (Choi's test p>0.05). Correlations between whole cord lesion volume and timed 25-foot walk were non-significant at 1.5 T and 3 T (p>0.05). Lesion number and volume did not differ between MRI platforms in the MS group (p>0.05).

CONCLUSIONS

Despite the use of higher field MRI strength, the link between spinal lesions and MS disability remains weak. The 1.5 T and 3 T protocols yielded similar results for many comparisons.

Natalizumab treatment is associated with peripheral sequestration of proinflammatory T cells

BACKGROUND

Natalizumab is an antibody directed against integrin alpha4 that reduces disease activity in patients with multiple sclerosis (MS) by blocking migration of T and B cells into the CNS. The goal of this study was to characterize the effects of natalizumab treatment on cytokine production and expression of activation markers, costimulatory molecules, and trafficking determinants on CD4+ and CD8+ T cells.

METHODS

In a longitudinal study, we investigated the expression of surface makers and cytokine expression on peripheral blood lymphocytes from 28 patients with MS who started natalizumab treatment and were followed for 1 year. A mixed effects model was used to compare pretreatment to on-treatment measurements.

RESULTS

The frequency of CD4+ T cells producing interferon-gamma, tumor necrosis factor, and interleukin (IL)-17 upon anti-CD3 stimulation increased 6 months after initiation of natalizumab treatment and remained elevated throughout the follow-up. The frequency of CD4+ T cells expressing CD25, HLA-DR, and CCR6 ex vivo was increased at one or more time points during treatment. Among CD8+ T cells, the frequency of cells producing IL-2 and IL-17 after stimulation was increased during natalizumab treatment, as was the frequency of CD8+ T cells expressing CD58 and CCR5 ex vivo. The increase in the frequency of activated cells could not be replicated by in vitro exposure to natalizumab.

CONCLUSION

Natalizumab treatment increases the percentage of activated leukocytes producing proinflammatory cytokines in blood, presumably due to sequestration of activated cells in the peripheral circulation.

T2 hypointensity in the deep gray matter of patients with benign multiple sclerosis

Background

Gray matter (GM) magnetic resonance imaging (MRI) T2 hypointensity, a putative marker of iron deposition, commonly occurs in multiple sclerosis (MS). However, GM T2 hypointensity in benign MS (BMS) has not yet been characterized.

Objective

To determine the presence of deep GM T2 hypointensity in BMS, compare it to secondary progressive (SP) MS and assess its association with clinical and diffusion tensor (DT) MRI measures.

Methods

Thirty-five cognitively unimpaired BMS, 26 SPMS patients, and 25 healthy controls were analyzed for normalized T2-intensity in the basal ganglia and thalamus, global T2 hyperintense lesion volume, global atrophy, and white matter and GM DT metrics.

Results

BMS and SPMS patients showed deep GM T2 hypointensity compared with controls. T2 hypointensity was similar in both MS subgroups and moderately correlated ( r = −0.45 to 0.42) with DT MRI metrics. GM T2 hypointensity in BMS showed a weak to moderate correlation ( r = −0.44 to −0.35) with disability.

Conclusions

GM in BMS is not spared from structural change including iron deposition. However, while T2 hypointensity is related to global tissue disruption reflected in DT MRI, the expression of benign versus non-benign MS is likely related to other factors.

Normal findings on brain fluid-attenuated inversion recovery MR images at 3T

BACKGROUND AND PURPOSE

Fluid attenuated inversion recovery (FLAIR) MR imaging of the brain has become a routine tool for assessing lesions in patients with suspected neurologic disorders. There is growing interest in 3T brain FLAIR MR imaging but little normative data are available. The purpose of this study was to evaluate the frequency and topography of cerebral hyperintensities seen with FLAIR MR imaging of the brain at 3T in a normal population and compare those findings to 1.5T.

MATERIALS AND METHODS

Whole-brain 2D FLAIR MR imaging was performed in 22 healthy controls (mean age, 44 +/- 8 years; range, 30-53 years) at 3T. Fifteen of these subjects also underwent 2D FLAIR at 1.5T, with similar optimized parameters and voxel size. Cerebral hyperintense areas, including discrete foci, anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts were assessed. The Spearman rank test assessed the correlation between discrete hyperintense foci and age. The Wilcoxon signed rank test compared foci detectability at 3T versus 1.5T.

RESULTS

FLAIR at 3T commonly showed hyperintensities such as discrete foci (mean, 10.68 per subject; at least 1 present in 68% of subjects), anterior and posterior periventricular capping, diffuse posterior white matter hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and ventricular CSF flow artifacts. FLAIR at 3T showed a higher hyperintense foci volume (170 +/- 243 versus 93 +/- 152 mm3, P < .01) and number (9.4 +/- 13 versus 5.5 +/- 9.2, P < .01) than at 1.5T. No significant differences (P = .68) in the length/diameter of individual discrete hyperintense foci were seen between 3T and 1.5T. Discrete foci volume (r = 0.72 at 3T, r = 0.70 at 1.5T) and number (r = 0.74 at 3T; r = 0.69 at 1.5T) correlated with age to a similar degree on both platforms. All discrete foci were confined to the noncallosal supratentorial white matter. The other nonfocal hyperintensities (anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts) were generally more common and prominent at 3T than at 1.5T.

CONCLUSIONS

Discrete and diffuse parenchymal brain white matter FLAIR hyperintensities are more common and prominent at 3T than at 1.5T in healthy volunteers.

Daclizumab in treatment of multiple sclerosis patients

BACKGROUND

Daclizumab is a humanized monoclonal antibody (mAb) that blocks the interleukin-2 receptor alpha subunit (IL-2R-alpha chain; CD25) expressed on activated T cells leading to the inhibition of T-cell expansion, thus strongly reduces brain inflammation in patients with multiple sclerosis (MS). Another mechanism is significant expansion of CD56 (bright) natural killer (NK) cells that in turn inhibit T-cell survival.

OBJECTIVE

At the Partners MS center, we have been using Daclizumab in an open-label fashion in patients who fail first line therapy or non-standard immunosuppressive treatment. Our aim was to assess its safety and tolerability in our patient population.

Medulla oblongata volume: a biomarker of spinal cord damage and disability in multiple sclerosis

BACKGROUND AND PURPOSE

While brain MR imaging is routinely performed, the MR imaging assessment of spinal cord pathology in multiple sclerosis (MS) is less frequent in clinical practice. The purpose of this study was to determine whether measurements of medulla oblongata volume (MOV) on routine brain MR imaging could serve as a biomarker of spinal cord damage and disability in MS.

MATERIALS AND METHODS

We identified 45 patients with MS with both head and cervical spinal cord MR imaging and 29 age-matched and sex-matched healthy control subjects with head MR imaging. Disability was assessed by the expanded disability status scale (EDSS) and ambulation index (AI). MOV and upper cervical cord volume (UCCV) were manually segmented; semiautomated segmentation was used for brain parenchymal fraction (BPF). These measures were compared between groups, and linear regression models were built to predict disability.

RESULTS

In the patients, MOV correlated significantly with UCCV (r = 0.67), BPF (r = 0.45), disease duration (r = -0.64), age (r = -0.47), EDSS score (r = -0.49) and AI (r = -0.52). Volume loss of the medulla oblongata was -0.008 cm(3)/year of age in patients with MS, but no significant linear relationship with age was found for healthy control subjects. The patients had a smaller MOV (mean +/- SD, 1.02 +/- 0.17 cm(3)) than healthy control subjects (1.15 +/- 0.15 cm(3)), though BPF was unable to distinguish between these 2 groups. MOV was smaller in patients with progressive MS (secondary- progressive MS, 0.88 +/- 0.19 cm(3) and primary-progressive MS, 0.95 +/- 0.30 cm(3)) than in patients with relapsing-remitting MS (1.08 +/- 0.15 cm(3)). A model including both MOV and BPF better predicted AI than BPF alone (P = .04). Good reproducibility in MOV measurements was demonstrated for intrarater (intraclass correlation coefficient, 0.97), interrater (0.79), and scan rescan data (0.81).

CONCLUSION

MOV is associated with disability in MS and can serve as a biomarker of spinal cord damage.

Bayesian inference of population expansions in domestic bovines

The past population dynamics of four domestic and one wild species of bovine were estimated using Bayesian skyline plots, a coalescent Markov chain Monte Carlo method that does not require an assumed parametric model of demographic history. Four domestic species share a recent rapid population expansion not visible in the wild African buffalo (Syncerus caffer). The estimated timings of the expansions are consistent with the archaeological records of domestication.