Stefan Traud

Universitätsspital Basel, Bâle, Basel-City, Switzerland

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Publications (12)58.2 Total impact

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    ABSTRACT: Segmentation of deep grey matter (DGM) using 2-dimensional MRI data is challenging.•We performed a systematic comparison between 2 and 3D data segmentation using FIRST.•The DGM volumes of 70 multiple sclerosis patients were statistically compared.•We found a good agreement of the segmentation results for the large DGM structures.•Our results indicate that FIRST is suitable for the segmentation of 2D data sets acquired in multicentre studies.
    Clinical neuroimaging 11/2014; 7. DOI:10.1016/j.nicl.2014.11.010 · 2.53 Impact Factor
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    ABSTRACT: In multiple sclerosis (MS) regional grey matter (GM) atrophy has been associated with disability progression. The aim of this study was to compare regional GM volume changes in relapsing-remitting MS (RRMS) patients with progressive and stable disability, using voxel-based morphometry (VBM). We acquired baseline and 1-year follow-up 3-dimensional (3D) T1-weighted magnetic resonance imaging (MRI) data of RRMS patients, using two 1.5-Tesla scanners. Patients were matched pair-wise with respect to age, gender, disease duration, medication, scanner and baseline Expanded Disability Status Scale (EDSS) into 13 pairs, with either progressive EDSS (≥ 1 point change y(-1)) or stable EDSS, as well as into 29 pairs with either progressive Multiple Sclerosis Functional Composite (MSFC) at ≥ 0.25% decrease in y(-1) in any component, or stable MSFC. We analysed longitudinal regional differences in GM volumes in the progressive and stable EDSS and MSFC groups, respectively, using VBM. Significant GM volume reductions occurred in the right precuneus, in the progressive EDSS group. Differential between-group effects occurred in the right precuneus and in the postcentral gyrus. Further longitudinal GM volume reductions occurred in the right orbicular gyrus, in the progressive MSFC group, but no between-group differences were observed (non-stationary cluster-wise inference, all Pcorrected < 0.05). These results suggested a direct association of disability progression and regional GM atrophy in RRMS.
    Multiple Sclerosis 06/2013; 20(2). DOI:10.1177/1352458513493034 · 4.86 Impact Factor
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    ABSTRACT: Voxel-based morphometry (VBM) has been used repeatedly in single-center studies to investigate regional gray matter (GM) atrophy in multiple sclerosis (MS). In multi-center trials, across-scanner variations might interfere with the detection of disease-specific structural abnormalities, thereby potentially limiting the use of VBM. Here we evaluated longitudinally inter-site differences and inter-site comparability of regional GM in MS using VBM. Baseline and follow up 3D T1-weighted magnetic resonance imaging (MRI) data of 248 relapsing-remitting (RR) MS patients, recruited in two clinical centers, (center1/2: n = 129/119; mean age 42.6 ± 10.7/43.3 ± 9.3; male:female 33:96/44:75; median disease duration 150 [72–222]/116 [60–156]) were acquired on two different 1.5T MR scanners. GM volume changes between baseline and year 2 while controlling for age, gender, disease duration, and global GM volume were analyzed. The main effect of time on regional GM volume was larger in data of center two as compared to center one in most of the brain regions. Differential effects of GM volume reductions occured in a number of GM regions of both hemispheres, in particular in the fronto-temporal and limbic cortex (cluster P corrected <0.05). Overall disease-related effects were found bilaterally in the cerebellum, uncus, inferior orbital gyrus, paracentral lobule, precuneus, inferior parietal lobule, and medial frontal gyrus (cluster P corrected <0.05). The differential effects were smaller as compared to the overall effects in these regions. These results suggest that the effects of different scanners on longitudinal GM volume differences were rather small and thus allow pooling of MR data and subsequent combined image analysis. Hum Brain Mapp, 2011. © 2011 Wiley-Liss, Inc.
    Human Brain Mapping 05/2012; 33(5):1225 - 1245. DOI:10.1002/hbm.21279 · 6.92 Impact Factor
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    ABSTRACT: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. MS lesions show a typical distribution pattern and primarily affect the white matter (WM) in the periventricular zone and in the centrum semiovale. To track lesion development during disease progression, we compared the spatiotemporal distribution patterns of lesions in relapsing-remitting MS (RRMS) and secondary progressive MS (SPMS). We used T1 and T2 weighted MR images of 209 RRMS and 62 SPMS patients acquired on two different 1.5 Tesla MR scanners in two clinical centers followed up for 25 (± 1.7) months. Both cross-sectional and longitudinal differences in lesion distribution between RRMS and SPMS patients were analyzed with lesion probability maps (LPMs) and permutation-based inference. MS lesions clustered around the lateral ventricles and in the centrum semiovale. Cross-sectionally, compared to RRMS patients, the SPMS patients showed a significantly higher regional probability of T1 hypointense lesions (p≤0.03) in the callosal body, the corticospinal tract, and other tracts adjacent to the lateral ventricles, but not of T2 lesions (peak probabilities were RRMS: T1 9%, T2 18%; SPMS: T1 21%, T2 27%). No longitudinal changes of regional T1 and T2 lesion volumes between baseline and follow-up scan were found. The results suggest a particular vulnerability to neurodegeneration during disease progression in a number of WM tracts.
    Multiple Sclerosis 04/2012; 18(11):1577-84. DOI:10.1177/1352458512442756 · 4.86 Impact Factor
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    ABSTRACT: Univariate analyses have identified gray matter (GM) alterations in different groups of MS patients. While these methods detect differences on the basis of the single voxel or cluster, multivariate methods like support vector machines (SVM) identify the complex neuroanatomical patterns of GM differences. Using multivariate linear SVM analysis and leave-one-out cross-validation, we aimed at identifying neuroanatomical GM patterns relevant for individual classification of MS patients. We used SVM to separate GM segmentations of T1-weighted three-dimensional magnetic resonance (MR) imaging scans within different age- and sex-matched groups of MS patients with either early (n=17) or late MS (n=17) (contrast I), low (n=20) or high (n=20) white matter lesion load (contrast II), and benign MS (BMS, n=13) or non-benign MS (NBMS, n=13) (contrast III) scanned on a single 1.5 T MR scanner. GM patterns most relevant for individual separation of MS patients comprised cortical areas of all the cerebral lobes as well as deep GM structures, including the thalamus and caudate. The patterns detected were sufficiently informative to separate individuals of the respective groups with high sensitivity and specificity in 85% (contrast I), 83% (contrast II) and 77% (contrast III) of cases. The study demonstrates that neuroanatomical spatial patterns of GM segmentations contain information sufficient for correct classification of MS patients at the single case level, thus making multivariate SVM analysis a promising clinical application.
    NeuroImage 03/2012; 60(1):400-8. DOI:10.1016/j.neuroimage.2011.12.070 · 6.36 Impact Factor
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    ABSTRACT: Persistent black holes (PBH) are associated with axonal loss and disability progression in multiple sclerosis (MS). The objective of this work was to determine if BHT-3009, a DNA plasmid-encoding myelin basic protein (MBP), reduces the risk of new lesions becoming PBH, compared to placebo, and to test if pre-treatment serum anti-MBP antibody levels impact on the effect of BHT-3009 treatment. In this retrospective, blinded MRI study, we reviewed MRI scans of 155 MS patients from a double-blind, randomized, phase II trial with three treatment arms (placebo, 0.5 and 1.5 mg BHT-3009). New lesions at weeks 8 and 16 were tracked at week 48 and those appearing as T1-hypointense were classified as PBH. A subset of 46 patients with available pre-treatment serum anti-MBP IgM levels were analyzed separately. Overall, there was no impact of treatment on the risk for PBH. However, there was a significant interaction between anti-MBP antibodies and treatment effect: patients receiving 0.5 mg BHT-3009 showed a reduced risk of PBH with higher antibody levels compared to placebo (p < 0.01). Although we found no overall reduction of the risk for PBH in treated patients, there may be an effect of low-dose BHT-3009, depending on the patients' pre-treatment immune responses.
    Journal of Neurology 01/2012; 259(7):1375-82. DOI:10.1007/s00415-011-6361-x · 3.84 Impact Factor
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    ABSTRACT: The association of white matter (WM) lesions and grey matter (GM) atrophy is a feature in relapsing-remitting multiple sclerosis (RRMS). The spatiotemporal distribution pattern of WM lesions, their relations to regional GM changes and the underlying dynamics are unclear. Here we combined parametric and non-parametric voxel-based morphometry (VBM) to clarify these issues. MRI data from RRMS patients with progressive (PLV, n = 45) and non-progressive WM lesion volumes (NPLV, n = 44) followed up for 12 months were analysed. Cross-sectionally, the spatial WM lesion distribution was compared using lesion probability maps (LPMs). Longitudinally, WM lesions and GM volumes were studied using FSL-VBM and SPM5-VBM, respectively. WM lesions clustered around the lateral ventricles and in the centrum semiovale with a more widespread pattern in the PLV than in the NPLV group. The maximum local probabilities were similar in both groups and higher for T2 lesions (PLV: 27%, NPLV: 25%) than for T1 lesions (PLV: 15%, NPLV 14%). Significant WM lesion changes accompanied by cortical GM volume reductions occurred in the corpus callosum and optic radiations (P = 0.01 corrected), and more liberally tested (uncorrected P < 0.01) in the inferior fronto-occipital and longitudinal fasciculi, and corona radiata in the PLV group. Not any WM or GM changes were found in the NPLV group. In the PLV group, WM lesion distribution and development in fibres, was associated with regional GM volume loss. The different spatiotemporal distribution patterns of patients with progressive compared to patients with non-progressive WM lesions suggest differences in the dynamics of pathogenesis.
    Human Brain Mapping 10/2010; 31(10):1542-55. DOI:10.1002/hbm.20951 · 6.92 Impact Factor
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    ABSTRACT: Prevention of global gray matter (GM) volume changes in multiple sclerosis (MS) are an objective in clinical trials, but the effect of immunomodulatory medication on regional GM atrophy progression is unclear. MRIs from 86 patients with relapsing-remitting MS (RRMS) followed up for 24 months were analyzed using voxel-based morphometry. An analysis of covariance model (cluster threshold, corrected p<0.05) was used to compare GM volumes between baseline and follow-up while stratified by immunomodulatory medication (IM): Interferone INF-beta-1a (n=34), INF-beta-1b (n=16), glatiramer acetate (GA) (n=15), and no-immunomodulatory treatment (n=21). In the INF-beta-1a/1b group (n=50), significant GM volume reductions were observed during follow-up in fronto-temporal, cingulate and cerebellar cortical brain regions, without significant differences between the INF-beta-1a and INF-beta-1b patients. In the GA group and in unmedicated patients, no significant regional GM volume reductions were observed. In contrast to GA, INF-beta-1a/1b treatment was associated with GM volume reductions in hippocampal/parahippocampal and anterior cingulate cortex. This is the first longitudinal study investigating the effects of IMs on GM in RRMS. Results suggest differences in the dynamics of regional GM volume atrophy in differentially treated or untreated RRMS patients.
    Brain research 02/2010; 1325:174-82. DOI:10.1016/j.brainres.2010.02.035 · 2.83 Impact Factor
  • NeuroImage 07/2009; 47. DOI:10.1016/S1053-8119(09)70124-7 · 6.36 Impact Factor
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    NeuroImage 07/2009; 47. DOI:10.1016/S1053-8119(09)70452-5 · 6.36 Impact Factor
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    ABSTRACT: Previous studies have established regional gray matter (GM) volume loss in multiple sclerosis (MS) but the relationship between development of white matter (WM) lesions and changes of regional GM volumes is unclear. The present study addresses this issue by means of voxel-based morphometry (VBM). T1-weighted three-dimensional magnetic resonance imaging (MRI) data from MS patients followed up for 12 months were analyzed using VBM. An analysis of covariance model assessed with cluster size inference (all corrected for multiple comparisons, p<0.01) was used to compare GM volumes between baseline and follow-up while controlling for age, gender, and disease duration. Lesion burden, i.e. volumes of T1 hypointense and T2 hyperintense lesions and the number of new T2 lesions at year one, was also determined. Comparing all MS patients (n=211) longitudinally, GM volume remained unchanged during one year-follow-up. Focusing on patients with relapsing remitting MS (RRMS) (n=151), significant cortical GM volume reductions between baseline and follow-up scans were found in the anterior and posterior cingulate, the temporal cortex, and cerebellum. Within the RRMS group, those patients with increasing T2 and T1 lesion burden (n=45) showed additional GM volume loss during follow-up in the frontal and parietal cortex, and precuneus. In contrast, patients lacking an increase in WM lesion burden (n=44) did not show any significant GM changes. The present study suggests that the progression of regional GM volume reductions is associated with WM lesion progression and occurs predominantly in fronto-temporal cortical areas.
    NeuroImage 10/2008; 45(1):60-7. DOI:10.1016/j.neuroimage.2008.10.006 · 6.36 Impact Factor
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    ABSTRACT: FA skeleton histogram (median) vs. T2w lesion load y = -0,0285x + 4347,4 p = 5 x 10 -16 3000 3500 4000 4500 5000 0 2000 4000 6000 8000 10000 T2w lesion load median [FA] median Linear (median) Fig. 3: Examplary slices from TBSS / RANDOMISE results, tfce corrected cluster size p<0.05. High-lighted overlays visualize the statistical tests FA |grpX > FA |grpY ; i. e. A) G1>G4 "low T2w lesion load vs. high T2w lesion load"; B) G2>G4 "low EDSS vs. high EDSS" in high T2w lesion load groups; the pyramidal tract is delineated along consecutive slices. Introduction: Pathological heterogeneity in multiple sclerosis (MS) still makes it difficult defining correlates between clinical status/symptoms and characteristics on the one hand, and structural tissue changes on the other hand. Usually, clinical scores (e. g. EDSS, MSSS) hardly correlate with MR imaging parameters like lesion load (T1w-black holes, T2w-hyperintense lesions) or global MR estimates (e. g. ADC and FA histograms derived from DW imaging). We investigate the contribution of the recently proposed approach of TBSS (tract based spatial statistics [1]) to characterize large cohorts of MS patients in more detail with respect to structural integrity as assessed by DT imaging. TBSS offers the advantages of whole brain voxelwise analyses of DW data, but still preserves spatial information in standard space. In this study, TBSS was carried out to investigate how white matter integrity can contribute to understand differences between patient groups with regard to their FA skeleton representation derived from DW imaging.