T1-Weighted Intensity Increase After a Single Administration of a Linear Gadolinium-Based Contrast Agent in Multiple Sclerosis

Purpose Through analysis of T1-weighted (T1w) images this study investigated gadolinium (Gd) deposition in the brain after administration of a linear (gadopentetic acid) and a cyclic (gadoteric acid) gadolinium-based contrast agent (GBCA) in patients with multiple sclerosis (MS), a disorder frequently requiring magnetic resonance imaging (MRI) scans over years. Methods A total of 3233 T1w images (unenhanced with respect to the same scanning session) of 881 MS patients were retrospectively analyzed. After spatial normalization and intensity scaling using a sphere within the pons, differences of all pairs of subsequent scans were calculated and attributed to either linear (nx202f;= 2718) or cyclic (nx202f;= 385) or no GBCA (nx202f;= 130) according to the first scan. Regional analyses were performed, focusing on the dentate nucleus, and whole brain analyses. By 1-sample t-tests, signal intensity increases within conditions were searched for;conditions were compared by 2-sample t-tests. Furthermore, recent hypotheses on the reversibility of GBCA deposition were tested. Results In the dentate nucleus, a significant increase was observed only after administration of linear GBCA even after a single GBCA administration. This increase differed significantly (px202f;< 0.001) from the other conditions (cyclic and no GBCA). Whole brain analyses revealed T1w signal increases only after administration of linear GBCA within two regions, the dentate nucleus and globus pallidus. Additional analyses did not indicate any decline of Gd deposition in the brain. Conclusion The data point towards Gd deposition in the brain after administration of linear GBCA even after a single administration

CSF parameters associated with early MRI activity in patients with MS

Objective To identify CSF parameters at diagnosis of clinically isolated syndrome (CIS) and MS that are associated with early inflammatory disease activity as measured by standardized cerebral MRI (cMRI). Methods One hundred forty-nine patients with newly diagnosed CIS and MS were included in the retrospective study. cMRI at onset and after 12 months was analyzed for T2 and gadolinium-enhancing lesions. CSF was tested for oligoclonal bands and intrathecal synthesis of immunoglobulin G (IgG), A (IgA), andM(IgM) before initiation of disease-modifying therapy (DMT). In a subgroup of patients, CSF and serum samples were analyzed for sCD27, neurofilament light chain, and IgG subclasses 1 and 3. Association between CSF parameters and cMRI activity was investigated by univariable and multivariable regression analysis in all patients, DMT-treated patients, and untreated patients. Results IgG index, sCD27 levels in CSF, and to a lesser extent IgM index were associated with the occurrence of new cMRI lesions. IgG index and sCD27 levels in CSF were highly correlated. In a multivariable analysis, IgG index and to a lesser extent IgM index together with DMT treatment status and gender were strongest predictors of future cMRI activity. Conclusions CSF parameters such as IgG and IgM index are independently associated with future MRI activity and thus might be helpful to support early treatment decisions in patients newly diagnosed with CIS and MS

Inner retinal layer thinning in radiologically isolated syndrome predicts conversion to multiple sclerosis

Background and purpose: Individuals with radiologically isolated syndrome (RIS) are at increased risk of converting to multiple sclerosis (MS). Early identification of later converters is crucial for optimal treatment decisions. The purpose of this study was to assess the predictive potential of optical coherence tomography (OCT) measures in individuals with RIS regarding conversion to MS. Methods: This prospective observational cohort study included 36 individuals with RIS and 36 healthy controls recruited from two German MS centers. All individuals received baseline OCT and clinical examination and were longitudinally followed over up to 6 years. The primary outcome measure was the conversion to MS. Results: During clinical follow-up of 46 (26-58) months (median, 25%-75% interquartile range), eight individuals with RIS converted to MS. Individuals converting to MS showed a thinning of the peripapillary retinal nerve fiber layer (pRNFL) and the common ganglion cell and inner plexiform layer (GCIP) at baseline and during follow-up. Individuals with a pRNFL of 99 mu m or lower or a GCIP of 1.99 mm(3)or lower were at a 7.5- and 8.0-fold risk for MS conversion, respectively, compared to individuals with higher measures. After correction for other known risk factors, Cox proportional hazards regression revealed a hazard ratio of 1.08 for conversion to MS for each 1 mu m decline in pRNFL. Conclusions: Reduction of the pRNFL might be a novel and independent risk factor for conversion to MS in individuals with RIS. OCT might be useful for risk stratification and therapeutic decision-making in individuals with RIS

Intra-and interscanner variability of magnetic resonance imaging based volumetry in multiple sclerosis

Brain volumetric measurements in multiple sclerosis (MS) reflect not only disease-specific processes but also other sources of variability. The latter has to be considered especially in multicenter and longitudinal studies. Here, we compare data generated by three different 3-Tesla magnetic resonance scanners (Philips Achieva; Siemens Verio; GE Signa MR750). We scanned two patients diagnosed with relapsing remitting MS six times per scanner within three weeks (T1w and FLAIR, 3D). We assessed T2-hyperintense lesions by an automated lesion segmentation tool and determined volumes of grey matter (GM), white matter (WM) and whole brain (GM + WM) from the lesion-filled T1-weighted images using voxel-based morphometry (SPM8/VBM8) and SIENAX (FSL). We measured cortical thickness using FreeSurfer from both, lesion-filled and original T1-weighted images. We quantified brain volume changes with SIENA. In both patients, we found significant differences in total lesion volume, global brain tissue volumes and cortical thickness measures between the scanners. Morphometric measures varied remarkably between repeated scans at each scanner, independent of the brain imaging software tool used. We conclude that for cross-sectional multicenter studies, the effect of different scanners has to be taken into account. For longitudinal monocentric studies, the expected effect size should exceed the size of false positive findings observed in this study. Assuming a physiological loss of brain volume of about 0.3% per year in healthy adult subjects (Good et al., 2001), which may double in MS (De Stefano et al., 2010; De Stefano et al., 2015), with current tools reliable estimation of brain atrophy in individual patients is only possible over periods of several years. (C) 2016 Elsevier Inc. All rights reserved

Automated segmentation of changes in FLAIR-hyperintense white matter lesions in multiple sclerosis on serial magnetic resonance imaging

Longitudinal analysis of white matter lesion changes on serial MRI has become an important parameter to study diseases with white-matter lesions. Here, we build on earlier work on cross-sectional lesion segmentation; we present a fully automatic pipeline for serial analysis of FLAIR-hyperintense white matter lesions. Our algorithm requires three-dimensional gradient echo T1- and FLAIR- weighted images at 3 Tesla as well as available cross-sectional lesion segmentations of both time points. Preprocessing steps include lesion filling and intrasubject registration. For segmentation of lesion changes, initial lesion maps of different time points are fused; herein changes in intensity are analyzed at the voxel level. Significance of lesion change is estimated by comparison with the difference distribution of FLAIR intensities within normal appearing white matter. The method is validated on MRI data of two time points from 40 subjects with multiple sclerosis derived from two different scanners (20 subjects per scanner). Manual segmentation of lesion increases served as gold standard. Across all lesion increases, voxel-wise Dice coefficient (0.7) as well as lesion-wise detection rate (0.8) and false-discovery rate (0.2) indicate good overall performance. Analysis of scans from a repositioning experiment in a single patient with multiple sclerosis did not yield a single false positive lesion. We also introduce the lesion change plot as a descriptive tool for the lesion change of individual patients with regard to both number and volume. An open source implementation of the algorithm is available at http//www.satastical-modeling.de/lst.html

Within-patient correspondence of amyloid-beta and intrinsic network connectivity in Alzheimer's disease

There is striking overlap between the spatial distribution of amyloid-beta pathology in patients with Alzheimer's disease and the spatial distribution of high intrinsic functional connectivity in healthy persons. This overlap suggests a mechanistic link between amyloid-beta and intrinsic connectivity, and indeed there is evidence in patients for the detrimental effects of amyloid-beta plaque accumulation on intrinsic connectivity in areas of high connectivity in heteromodal hubs, and particularly in the default mode network. However, the observed spatial extent of amyloid-beta exceeds these tightly circumscribed areas, suggesting that previous studies may have underestimated the negative impact of amyloid-beta on intrinsic connectivity. We hypothesized that the known positive baseline correlation between patterns of amyloid-beta and intrinsic connectivity may mask the larger extent of the negative effects of amyloid-beta on connectivity. Crucially, a test of this hypothesis requires the within-patient comparison of intrinsic connectivity and amyloid-beta distributions. Here we compared spatial patterns of amyloid-beta-plaques (measured by Pittsburgh compound B positron emission tomography) and intrinsic functional connectivity (measured by resting-state functional magnetic resonance imaging) in patients with prodromal Alzheimer's disease via spatial correlations in intrinsic networks covering fronto-parietal heteromodal cortices. At the global network level, we found that amyloid-beta and intrinsic connectivity patterns were positively correlated in the default mode and several fronto-parietal attention networks, confirming that amyloid-beta aggregates in areas of high intrinsic connectivity on a within-network basis. Further, we saw an internetwork gradient of the magnitude of correlation that depended on network plaque-load. After accounting for this globally positive correlation, local amyloid-beta-plaque concentration in regions of high connectivity co-varied negatively with intrinsic connectivity, indicating that amyloid-beta pathology adversely reduces connectivity anywhere in an affected network as a function of local amyloid-beta-plaque concentration. The local negative association between amyloid-beta and intrinsic connectivity was much more pronounced than conventional group comparisons of intrinsic connectivity would suggest. Our findings indicate that the negative impact of amyloid-beta on intrinsic connectivity in heteromodal networks is underestimated by conventional analyses. Moreover, our results provide first within-patient evidence for correspondent patterns of amyloid-beta and intrinsic connectivity, with the distribution of amyloid-beta pathology following functional connectivity gradients within and across intrinsic networks