Publications by authors named "Michael Deppe"

64 Publications

Longitudinal optic neuritis-unrelated visual evoked potential changes in NMO spectrum disorders.

Neurology 2020 01 3;94(4):e407-e418. Epub 2019 Dec 3.

From the Department of Neurology, Medical Faculty (M.R., J. Harmel, J.G., H.-P.H., O.A., P.A.), and Department of Neurology, Center for Neurology and Neuropsychiatry, LVR-Klinikum (M.R.), Heinrich Heine University Düsseldorf; NeuroCure Clinical Research Center and Experimental and Clinical Research Center (H.Z., A.U.B., F.P.), Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, and Max Delbrueck Center for Molecular Medicine, Germany; Department of Neurology (A.U.B.), University of California Irvine; Department of Neurology (A.H., M.B.), University of Würzburg; Department of Neurology (M.B.), Caritas Hospital, Bad Mergentheim; Clinical Neuroimmunology and Neurochemistry (M.W.H.), Department of Neurology (C.T.), Hannover Medical School; Department of Neurology (C.S., I.A., I.K., K.H.), St. Josef Hospital, Ruhr University Bochum, Germany; Department of Neurology (I.A.), Sechenov First Moscow State Medical University, Moscow, Russia; Marianne-Strauß-Klinik (I.K.), Behandlungszentrum Kempfenhausen für Multiple Sklerose Kranke, Berg; Institute of Clinical Neuroimmunology (J. Halva, T.K., H.P.), University Hospital, Ludwig-Maximilians University, Munich; Molecular Neuroimmunology Group, Department of Neurology (S.J., B.W.), University of Heidelberg, Germany; Department of Neurology (P.R.), Medical University of Vienna, Austria; Institute of Neuropathology (M.S.W.) and Department of Neurology (M.S.W., H.P., P.K.), University Medical Center Göttingen; Department of Neurology (L.R., C.G.), Jena University Hospital; Neuroimmunological Section, Department of Neurology (N.R., U.Z.), University of Rostock; Department of Neurology (M.D., L.K.), University of Münster; Department of Neurology and Institute of Neuroimmunology and MS (K.Y., J.-P.S.), University Medical Center Hamburg-Eppendorf; Department of Neurology (M.K., P.K.), Nordwest-Hospital Sanderbusch, Sande; Department of Neurology (W.M.), Helios Hanseklinikum Stralsund; Department of Neurology (F.L., H.T.), University of Ulm, Germany; and Faculty of Medicine and Health Sciences (A.K.), Macquarie University, Sydney, New South Wales, Australia.

Objective: To investigate if patients with neuromyelitis optica spectrum disorder (NMOSD) develop subclinical visual pathway impairment independent of acute attacks.

Methods: A total of 548 longitudinally assessed full-field visual evoked potentials (VEP) of 167 patients with NMOSD from 16 centers were retrospectively evaluated for changes of P100 latencies and P100-N140 amplitudes. Rates of change in latencies (RCL) and amplitudes (RCA) over time were analyzed for each individual eye using linear regression and compared using generalized estimating equation models.

Results: The rates of change in the absence of optic neuritis (ON) for minimal VEP intervals of ≥3 months between baseline and last follow-up were +1.951 ms/y (n = 101 eyes; SD = 6.274; = 0.012) for the P100 latencies and -2.149 µV/y (n = 64 eyes; SD = 5.013; = 0.005) for the P100-N140 amplitudes. For minimal VEP intervals of ≥12 months, the RCL was +1.768 ms/y (n = 59 eyes; SD = 4.558; = 0.024) and the RCA was -0.527 µV/y (n = 44 eyes; SD = 2.123; = 0.111). The history of a previous ON >6 months before baseline VEP had no influence on RCL and RCA. ONs during the observational period led to mean RCL and RCA of +11.689 ms/y (n = 16 eyes; SD = 17.593; = 0.003) and -1.238 µV/y (n = 11 eyes; SD = 3.708; = 0.308), respectively.

Conclusion: This first longitudinal VEP study of patients with NMOSD provides evidence of progressive VEP latency delay occurring independently of acute ON. Prospective longitudinal studies are needed to corroborate these findings and help to interpret the clinical relevance.
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http://dx.doi.org/10.1212/WNL.0000000000008684DOI Listing
January 2020

Widespread white matter microstructural abnormalities in bipolar disorder: evidence from mega- and meta-analyses across 3033 individuals.

Neuropsychopharmacology 2019 12 21;44(13):2285-2293. Epub 2019 Aug 21.

Department of Psychiatry, Royal Edinburgh Hospital, Edinburgh, UK.

Fronto-limbic white matter (WM) abnormalities are assumed to lie at the heart of the pathophysiology of bipolar disorder (BD); however, diffusion tensor imaging (DTI) studies have reported heterogeneous results and it is not clear how the clinical heterogeneity is related to the observed differences. This study aimed to identify WM abnormalities that differentiate patients with BD from healthy controls (HC) in the largest DTI dataset of patients with BD to date, collected via the ENIGMA network. We gathered individual tensor-derived regional metrics from 26 cohorts leading to a sample size of N = 3033 (1482 BD and 1551 HC). Mean fractional anisotropy (FA) from 43 regions of interest (ROI) and average whole-brain FA were entered into univariate mega- and meta-analyses to differentiate patients with BD from HC. Mega-analysis revealed significantly lower FA in patients with BD compared with HC in 29 regions, with the highest effect sizes observed within the corpus callosum (R = 0.041, P < 0.001) and cingulum (right: R = 0.041, left: R = 0.040, P < 0.001). Lithium medication, later onset and short disease duration were related to higher FA along multiple ROIs. Results of the meta-analysis showed similar effects. We demonstrated widespread WM abnormalities in BD and highlighted that altered WM connectivity within the corpus callosum and the cingulum are strongly associated with BD. These brain abnormalities could represent a biomarker for use in the diagnosis of BD. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.
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http://dx.doi.org/10.1038/s41386-019-0485-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6898371PMC
December 2019

Non-lesional cerebellar damage in patients with clinically isolated syndrome: DTI measures predict conversion into clinically definite multiple sclerosis.

Neuroimage Clin 2018 24;19:633-639. Epub 2018 Apr 24.

Department of Neurology, Westfälische Wilhelms University, Münster, Germany.

Background: Today, no specific test for the diagnosis of multiple sclerosis (MS) is available due to the lack of characteristic symptoms at beginning. This circumstance also complicates estimation of disease progression. Recent findings provided evidence for early, non-lesional cerebellar damage in patients with (clinically definite) relapsing-remitting MS.

Objective: To investigate if microstructural cerebellar alterations can also serve as early structural biomarker for disease progression and conversion from clinically isolated syndrome (CIS) to MS.

Methods: 46 patients diagnosed with CIS and 26 age-matched healthy controls were admitted to high-resolution MRI including diffusion tensor imaging (DTI) to examine atrophy and microstructural integrity of the cerebellum. Microstructural integrity of cerebellar white matter was assessed by fractional anisotropy (FA) as derived from DTI.

Results: Although all 46 patients of our CIS cohort showed no cerebellar lesions in structural MRI (T1w, T2w, FLAIR), their mean cerebellar FA was already reduced compared to healthy controls. Significant FA reduction at follow-up DTI 6 months after baseline examination was observed. In 16 patients that converted to MS, we found a correlation between initial cerebellar FA and conversion latency ( = 0.71,  < 0.002). Initial cerebellar FA under FA = 0.352 predicted conversion into relapsing-remitting MS within 24 months (FA: mean cerebellar FA of patients with early MS, determined in another study).

Conclusion: DTI seems to reflect early tissue injury in beginning MS, when atrophy and lesions are not yet detectable. Decreased cerebellar FA in patients with CIS might indicate an active and unstable disease stage, resulting in a shorter conversion time into MS.
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http://dx.doi.org/10.1016/j.nicl.2018.04.028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6031094PMC
January 2019

A voxel-based diffusion tensor imaging study in unipolar and bipolar depression.

Bipolar Disord 2017 02 27;19(1):23-31. Epub 2017 Feb 27.

Department of Psychiatry, University of Münster, Münster, Germany.

Objective: The absence of neurobiological diagnostic markers of bipolar disorder (BD) leads to its frequent misdiagnosis as unipolar depression (UD). We investigated if changes in fractional anisotropy (FA) could help to differentiate BD from UD in the state of depression.

Methods: Using diffusion tensor imaging (DTI) we employed a voxel-based analysis approach to examine fractional anisotropy (FA) in 86 patients experiencing an acute major depressive episode according to DSM-IV (N=39 BD, mean age 39.2 years; N=43 UD, mean age 39.0 years), and 42 healthy controls (HC, mean age 36.1 years). The groups did not differ in sex, age or total education time. FA was investigated in white matter (FA >.2) and hypothesis-driven anatomically defined tracts (region-of-interest [ROI] analysis). Additionally, an exploratory gray matter FA analysis was performed.

Results: White matter analysis showed decreased FA in the right corticospinal tract in UD vs HC and in the right corticospinal tract/superior longitudinal fascicle in BD vs HC and also in BD vs UD. ROI analysis revealed decreased FA in BD vs UD in the corpus callosum and in the cingulum. Gray matter exploratory analysis revealed decreased FA in the left middle frontal gyrus and in the right inferior frontal gyrus in UD vs HC, and in the left superior medial gyrus in BD vs HC.

Conclusion: This is one of very few studies directly showing differences in FA between BD and UD. Gray matter FA changes in prefrontal areas might be precursors for future prefrontal gray matter abnormalities in these disorders.
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http://dx.doi.org/10.1111/bdi.12465DOI Listing
February 2017

Neurochondrin is a neuronal target antigen in autoimmune cerebellar degeneration.

Neurol Neuroimmunol Neuroinflamm 2017 Jan 5;4(1):e307. Epub 2016 Dec 5.

Institute of Experimental Immunology (R.M., M. Scharf, I.M.D., S.M., Y.D., B.T., C.P., S.B., W.S., L.K.), Euroimmun AG, Lübeck; Department of Neurology (C.C.G., K.S.G., M.H., U.B., A.S.-M., K.B., C.S., H.L., M.D., T.W., H.W., S.G.M., N.M.), University of Münster; Centre for Neurology and Hertie-Institute for Clinical Brain Research (L.S., M. Synofzik), Tübingen; German Center for Neurodegenerative Diseases (DZNE) (L.S., M. Synofzik), Tübingen; and Institute of Clinical Chemistry and Department of Neurology (K.-P.W.), University Hospital of Schleswig-Holstein, Lübeck, Germany.

Objective: To report on a novel neuronal target antigen in 3 patients with autoimmune cerebellar degeneration.

Methods: Three patients with subacute to chronic cerebellar ataxia and controls underwent detailed clinical and neuropsychological assessment together with quantitative high-resolution structural MRI. Sera and CSF were subjected to comprehensive autoantibody screening by indirect immunofluorescence assay (IFA) and immunoblot. Immunoprecipitation with lysates of hippocampus and cerebellum combined with mass spectrometric analysis was used to identify the autoantigen, which was verified by recombinant expression in HEK293 cells and use in several immunoassays. Multiparameter flow cytometry was performed on peripheral blood and CSF, and peripheral blood was subjected to T-cell receptor spectratyping.

Results: Patients presented with a subacute to chronic cerebellar and brainstem syndrome. MRI was consistent with cortical and cerebellar gray matter atrophy associated with subsequent neuroaxonal degeneration. IFA screening revealed strong immunoglobulin G1 reactivity in sera and CSF with hippocampal and cerebellar molecular and granular layers, but not with a panel of 30 recombinantly expressed established neural autoantigens. Neurochondrin was subsequently identified as the target antigen, verified by IFA and immunoblot with HEK293 cells expressing human neurochondrin as well as the ability of recombinant neurochondrin to neutralize the autoantibodies' tissue reaction. Immune phenotyping revealed intrathecal accumulation and activation of B and T cells during the acute but not chronic phase of the disease. T-cell receptor spectratyping suggested an antigen-specific T-cell response accompanying the formation of antineurochondrin autoantibodies. No such neurochondrin reactivity was found in control cohorts of various neural autoantibody-associated neurologic syndromes, relapsing-remitting multiple sclerosis, cerebellar type of multiple system atrophy, hereditary cerebellar ataxias, other neurologic disorders, or healthy donors.

Conclusion: Neurochondrin is a neuronal target antigen in autoimmune cerebellar degeneration.
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http://dx.doi.org/10.1212/NXI.0000000000000307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5141526PMC
January 2017

Early silent microstructural degeneration and atrophy of the thalamocortical network in multiple sclerosis.

Hum Brain Mapp 2016 May 27;37(5):1866-79. Epub 2016 Feb 27.

Department of Neurology, Westfälische Wilhelms University, Münster, Germany.

Recent studies on patients with clinically isolated syndrome (CIS) and multiple sclerosis (MS) demonstrated thalamic atrophy. Here we addressed the following question: Is early thalamic atrophy in patients with CIS and relapsing-remitting MS (RRMS) mainly a direct consequence of white matter (WM) lesions-as frequently claimed-or is the atrophy stronger correlated to "silent" (nonlesional) microstructural thalamic alterations? One-hundred and ten patients with RRMS, 12 with CIS, and 30 healthy controls were admitted to 3 T magnetic resonance imaging. Fractional anisotropy (FA) was computed from diffusion tensor imaging (DTI) to assess thalamic and WM microstructure. The relative thalamic volume (RTV) and thalamic FA were significantly reduced in patients with CIS and RRMS relative to healthy controls. Both measures were also correlated. The age, gender, WM lesion load, thalamic FA, and gray matter volume-corrected RTV were reduced even in the absence of thalamic and extensive white matter lesions-also in patients with short disease duration (≤24 months). A voxel-based correlation analysis revealed that the RTV reduction had a significant effect on local WM FA-in areas next to the thalamus and basal ganglia. These WM alterations could not be explained by WM lesions, which had a differing spatial distribution. Early thalamic atrophy is mainly driven by silent microstructural thalamic alterations. Lesions do not disclose the early damage of thalamocortical circuits, which seem to be much more affected in CIS and RRMS than expected. Thalamocortical damage can be detected by DTI in normal appearing brain tissue. Hum Brain Mapp 37:1866-1879, 2016. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/hbm.23144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6867391PMC
May 2016

TCD-Profiling Using AVERAGE. A New Technique to Evaluate Transcranial Doppler Ultrasound Flow Spectra of Subjects with Cerebral Small Vessel Disease.

Cerebrovasc Dis 2016 25;41(1-2):50-9. Epub 2015 Nov 25.

Department of Neurology, University Hospital Muenster, Muenster, Germany.

Background: There is an unmet need for screening methods to detect and quantify cerebral small vessel disease (SVD). Transcranial Doppler ultrasound (TCD) flow spectra of the larger intracranial arteries probably contain relevant information about the microcirculation. However, it has not yet been possible to exploit this information as a valuable biomarker.

Methods: We developed a technique to generate normalized and averaged flow spectra during middle cerebral artery Doppler ultrasound examinations. Second, acceleration curves were calculated, and the absolute amount of the maximum positive and negative acceleration was calculated. Findings were termed 'TCD-profiling coefficient' (TPC). Validation study: we applied this noninvasive method to 5 young adults for reproducibility. Degenerative microangiopathy study: we also tested this new technique in 30 elderly subjects: 15 free of symptoms but with MRI-verified presence of cerebral SVD, and 15 healthy controls. SVD severity was graded according to a predefined score. Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) study: TPC values of 10 CADASIL patients were compared with those of 10 healthy controls. Pulse wave analysis and local measurements of carotid stiffness were also performed. CADASIL patients were tested for cognitive impairment with the Montreal Cognitive Assessment scale. White matter and basal ganglia lesions in their cerebral MRI were evaluated according to the Wahlund score.

Results: Validation study: the technique delivered reproducible results. Degenerative microangiopathy study: patients with SVD had significantly larger TPCs compared with controls (SVD: 2,132; IQR 1,960-2,343%/s vs.

Controls: 1,935; IQR 1,782-2,050%/s, p = 0.01). TPC values of subjects with SVD significantly correlated with SVD severity scores (R = 0.58, n = 15, p < 0.05). CADASIL study: TPC values of CADASIL patients were significantly higher than values of the controls (CADASIL: 2,504; IQR 2,308-2,930%/s vs. controls 2,084; 1,839-2,241%/s, p = 0.008), and also significantly higher than the TPC values of the patients with SVD from the degenerative microangiopathy study (p = 0.007). CADASIL patients had significantly worse cognitive test results than healthy controls.

Conclusion: TCD-profiling detects impairment of the cerebral microcirculatory state. The suitability of the TCD-profiling for the evaluation of cerebral microangiopathy was confirmed.
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http://dx.doi.org/10.1159/000441921DOI Listing
November 2016

Deficits in tongue motor control are linked to microstructural brain damage in multiple sclerosis: a pilot study.

BMC Neurol 2015 Oct 8;15:190. Epub 2015 Oct 8.

George-Huntington-Institute, Technology Park Muenster, Johann-Krane-Weg 27, 48149, Muenster, Germany.

Background: Deterioration of fine motor control of the tongue is common in Multiple Sclerosis (MS) and has a major impact on quality of life. However, the underlying neuronal substrate is largely unknown. Here, we aimed to explore the association of tongue motor dysfunction in MS patients with overall clinical disability and structural brain damage.

Methods: We employed a force transducer based quantitative-motor system (Q-Motor) to objectively assess tongue function in 33 patients with MS. The variability of tongue force output (TFV) and the mean applied tongue force (TF) were measured during an isometric tongue protrusion task. Twenty-three age and gender matched healthy volunteers served as controls. Correlation analyses of motor performance in MS patients with individual disease burden as expressed by the Expanded Disability Status Scale (EDSS) and with microstructural brain damage as measured by the fractional anisotropy (FA) on Diffusion Tensor Imaging were performed.

Results: MS patients showed significantly increased TFV and decreased TF compared to controls (p < 0.02). TFV but not TF was correlated with the EDSS (p < 0.04). TFV was inversely correlated with FA in the bilateral posterior limb of the internal capsule expanding to the brain stem (p < 0.001), a region critical to tongue function. TF showed a weaker, positive and unilateral correlation with FA in the same region (p < 0.001).

Conclusions: Changes in TFV were more robust and correlated better with disease phenotype and FA changes than TF. TFV might serve as an objective and non-invasive outcome measure to augment the quantitative assessment of motor dysfunction in MS.
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http://dx.doi.org/10.1186/s12883-015-0451-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4599335PMC
October 2015

Early and Degressive Putamen Atrophy in Multiple Sclerosis.

Int J Mol Sci 2015 Sep 25;16(10):23195-209. Epub 2015 Sep 25.

Department of Neurology, Westfälische Wilhelms University, Albert-Schweitzer-Campus 1, Gebäude A1, 48149 Münster, Germany.

Putamen atrophy and its long-term progress during disease course were recently shown in patients with multiple sclerosis (MS). Here we investigated retrospectively the time point of atrophy onset in patients with relapsing-remitting MS (RRMS). 68 patients with RRMS and 26 healthy controls (HC) were admitted to 3T MRI in a cross-sectional study. We quantitatively analyzed the putamen volume of individual patients in relation to disease duration by correcting for age and intracranial volume (ICV). Patient's relative putamen volume (RPV), expressed in percent of ICV, was significantly reduced compared to HC. Based on the correlation between RPV and age, we computed the age-corrected RPV deviation (ΔRPV) from HC. Patients showed significantly negative ΔRPV. Interestingly, the age-corrected ΔRPV depended logarithmically on disease duration: Directly after first symptom manifestation, patients already showed a reduced RPV followed by a further degressive volumetric decline. This means that atrophy progression was stronger in the first than in later years of disease. Putamen atrophy starts directly after initial symptom manifestation or even years before, and progresses in a degressive manner. Due to its important role in neurological functions, early detection of putamen atrophy seems necessary. High-resolution structural MRI allows monitoring of disease course.
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http://dx.doi.org/10.3390/ijms161023195DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4632693PMC
September 2015

FDG μPET Fails to Detect a Disease-Specific Phenotype in Rats Transgenic for Huntington's Disease – A 15 Months Follow-up Study.

J Huntingtons Dis 2015 ;4(1):37-47

George-Huntington-Institute, Muenster, Germany.

Background: FDG-PET detects hypometabolism in premanifest and symptomatic Huntington's disease (HD). A cross-sectional study suggested that whole-brain FDG-PET is capable to detect a phenotype in transgenic (tg) HD rats. Recently, a longitudinal follow-up study showed no FDG-PET changes in tgHD rats. Both studies applied small sample sizes and analysis was limited to whole-brain or striatum.

Objective: We therefore performed a follow-up study in a larger cohort of tgHD and wild-type (wt) rats encompassing several pre-defined regions of interest (ROIs) and hypothesis free voxel-by-voxel SPM analysis to clarify whether FDG-PET can detect a phenotype in tgHD rats and to determine onset …and effect sizes of changes over time.

Methods: N = 19 tgHD- and n = 20 wt-rats, mixed gender, were included. Repeated small animal FDG-μPET and MRI were performed at 5,10,15, and 20 months of age. ROIs encompassing entire brain, cortex, striatum, thalamus, subventricular-zone, and cerebellum were placed manually on the MRI and transferred to the co-registered μPET. Mean and maximal FDG-PET activities within ROIs were calculated and normalized to cerebellar FDG uptake. Activity and spatially normalized FDG-μPET were compared between groups on a hypothesis-free voxel-by-voxel basis using SPM.

Results: FDG uptake showed changes over time in both tgHD- and wt-rats, however, there was no consistent difference between tgHD- and wt-rats in both the manual ROI and SPM analysis.

Conclusions: In this transgenic rat model of HD FDG-μPET imaging does not detect significant alterations at the ages investigated. Further investigations are warranted employing other age groups and alternative imaging biomarkers for neuronal degeneration, respectively.
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October 2015

Recovery of thalamic microstructural damage after Shiga toxin 2-associated hemolytic-uremic syndrome.

J Neurol Sci 2015 Sep 23;356(1-2):175-83. Epub 2015 Jun 23.

Department of Neurology, Westfälische Wilhelms University, Albert-Schweitzer-Campus 1, Gebäude A1, 48149 Münster, Germany. Electronic address:

Introduction: The underlying pathophysiology of neurological complications in patients with hemolytic-uremic syndrome (HUS) remains unclear. It was recently attributed to a direct cytotoxic effect of Shiga toxin 2 (Stx2) in the thalamus. Conventional MRI of patients with Stx2-caused HUS revealed - despite severe neurological symptoms - only mild alterations if any, mostly in the thalamus. Against this background, we questioned: Does diffusion tensor imaging (DTI) capture the thalamic damage better than conventional MRI? Are neurological symptoms and disease course better reflected by thalamic alterations as detected by DTI? Are other brain regions also affected?

Methods: Three women with serious neurological deficits due to Stx2-associated HUS were admitted to MRI/DTI at disease onset. Two of them were longitudinally examined. Fractional anisotropy (FA) and mean diffusivity were computed to assess Stx2-caused microstructural damage.

Results: Compared to 90 healthy women, all three patients had significantly reduced thalamic FA. Thalamic mean diffusivity was only reduced in two patients. DTI of the longitudinally examined women demonstrated slow normalization of thalamic FA, which was paralleled by clinical improvement.

Conclusion: Whereas conventional MRI only shows slight alterations based on subjective evaluation, DTI permits quantitative, objective, and longitudinal assessment of cytotoxic cerebral damage in individual patients.
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http://dx.doi.org/10.1016/j.jns.2015.06.045DOI Listing
September 2015

Assessment of immune functions and MRI disease activity in relapsing-remitting multiple sclerosis patients switching from natalizumab to fingolimod (ToFingo-Successor).

BMC Neurol 2015 Jun 23;15:96. Epub 2015 Jun 23.

Department of neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, building A1, Münster, 48149, Germany.

Background: In light of the increased risk of progressive multifocal encephalopathy (PML) development under long-term treatment with the monoclonal antibody natalizumab which is approved for treatment of active relapsing remitting multiple sclerosis (RRMS), there is a clear need for alternative treatment options with comparable efficacy and reduced PML risk. One such option is fingolimod, a functional sphingosin-1-receptor antagonist that has been approved as first oral drug for treatment of active RRMS. However, the optimal switching design in terms of prevention of disease reoccurrence is still unknown. Moreover, potential additive effects of both drugs on immune functions, especially with regard to migration, have not yet been evaluated.

Methods/design: This is an exploratory, open-label, monocentric, investigator-initiated clinical trial. Fifteen RRMS patients under stable treatment with natalizumab will receive one last natalizumab infusion followed by a wash-out period of 8 weeks before fingolimod treatment initiation for a period of 24 weeks. Disease activity under natalizumab and during switching will be closely monitored by assessment of relapse rate and disease severity as well as high-frequent high-resolution magnetic resonance imaging including quantitative diffusion tensor imaging. Immunological assays include longitudinal assessment of adhesion molecule expression, functional evaluation of the migratory capacity of immune cells in an in-vitro model of the blood-brain-barrier, and the quality of cellular antiviral immune responses.

Discussion: Our trial represents the first detailed and longitudinal functional analysis of key immunological parameters in the process of switching from natalizumab and fingolimod, especially with regard to potential additive effects of both drugs on trafficking and immune surveillance. Moreover, our study will generate valuable information about even subtle disease exacerbations as consequence of natalizumab cessation, which will help to understand whether a switching protocol containing a wash-out period of 8 weeks before fingolimod treatment is appropriate in terms of disease stability.
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http://dx.doi.org/10.1186/s12883-015-0354-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4477482PMC
June 2015

Evidence for early, non-lesional cerebellar damage in patients with multiple sclerosis: DTI measures correlate with disability, atrophy, and disease duration.

Mult Scler 2016 Jan 28;22(1):73-84. Epub 2015 Apr 28.

Department of Neurology, Westfälische Wilhelms University, Albert-Schweitzer-Campus 1, Gebäude A1, Münster, 48149, Germany.

Background: Common symptoms of multiple sclerosis (MS) such as gait ataxia, poor coordination of the hands, and intention tremor are usually the result of dysfunctionality in the cerebellum. Magnetic resonance imaging (MRI) has frequently failed to detect cerebellar damage in the form of inflammatory lesions in patients presenting with symptoms of cerebellar dysfunction.

Objective: To detect microstructural cerebellar tissue alterations in early MS patients with a "normal appearing" cerebellum using diffusion tensor imaging (DTI).

Methods: A total of 68 patients with relapsing-remitting MS (RRMS) and without cerebellar lesions and 26 age-matched healthy controls were admitted to high-resolution MRI and DTI to assess microstructure and volume of the cerebellar white matter (CBWM).

Results: We found cerebellar fractional anisotropy (FA) and CBWM volume reductions in the group of 68 patients. Interestingly, a subgroup of these patients that was derived by including only patients with early and mild MS (N=23, median age 30 years, median Expanded Disability Status Scale =1.5, median duration 28 months) showed already cerebellar FA but no CBWM volume reductions. FA reductions were correlated with disability, atrophy, and disease duration.

Conclusion: "Normal appearing" cerebellar white matter can be damaged in a very early stage of RRMS. DTI seems to be a sensitive tool for detecting this hidden cerebellar damage.
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http://dx.doi.org/10.1177/1352458515579439DOI Listing
January 2016

Volume transition analysis: a new approach to resolve reclassification of brain tissue in repeated MRI scans.

J Neurosci Methods 2015 Mar 18;243:78-83. Epub 2015 Feb 18.

Institute of Epidemiology and Social Medicine, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany.

Background: Variability in brain tissue volumes derived from magnetic resonance images is attributable to various sources. In quantitative comparisons it is therefore crucial to distinguish between biologically and methodically conditioned variance and to take spatial accordance into account.

New Method: We introduce volume transition analysis as a method that not only provides details on numerical and spatial accordance of tissue volumes in repeated scans but also on voxel shifts between tissue types. Based on brain tissue probability maps, mono- and bidirectional voxel shifts can be examined by explicitly separating volume transitions into source and target. We apply the approach to a set of subject data from repeated intra-scanner (one week and 30 month interval) as well as inter-scanner measurements.

Results: In all measurement scenarios, we found similar inter-class transitions of 9.9-15.9% of intracranial volume. The percentage of monodirectional net volume transition however increases from 0.3% in short term intra-scanner to 1.6% in long term intra-scanner and 9.3% in inter-scanner comparisons.

Comparison With Existing Methods: Unlike most routinely used variability measures volume transition analysis is able to monitor reclassifications and thus to quantify not only balanced flows but also the amount of monodirectional net flows between tissue classes. The approach is independent from group analysis and can thus be applied in as few as two images.

Conclusions: The proposed method is an easily applicable tool that is useful in discovering intra-individual brain changes and assists in separating biological from technical variance in structural brain measures.
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http://dx.doi.org/10.1016/j.jneumeth.2015.01.028DOI Listing
March 2015

Increased cortical curvature reflects white matter atrophy in individual patients with early multiple sclerosis.

Neuroimage Clin 2014 3;6:475-87. Epub 2014 Mar 3.

Department of Neurology, Westfälische Wilhelms University, Münster, Germany.

Objective: White matter atrophy occurs independently of lesions in multiple sclerosis. In contrast to lesion detection, the quantitative assessment of white matter atrophy in individual patients has been regarded as a major challenge. We therefore tested the hypothesis that white matter atrophy (WMA) is present at the very beginning of multiple sclerosis (MS) and in virtually each individual patient. To find a new sensitive and robust marker for WMA we investigated the relationship between cortical surface area, white matter volume (WMV), and whole-brain-surface-averaged rectified cortical extrinsic curvature. Based on geometrical considerations we hypothesized that cortical curvature increases if WMV decreases and the cortical surface area remains constant.

Methods: In total, 95 participants were enrolled: 30 patients with early and advanced relapsing-remitting MS; 30 age-matched control subjects; 30 patients with Alzheimer's disease (AD) and 5 patients with clinically isolated syndrome (CIS).

Results: 29/30 MS and 5/5 CIS patients showed lower WMV than expected from their intracranial volume (average reduction 13.0%, P < 10(- 10)), while the cortical surface area showed no significant differences compared with controls. The estimated WMV reductions were correlated with an increase in cortical curvature (R = 0.62, P = 0.000001). Discriminant analysis revealed that the curvature increase was highly specific for the MS and CIS groups (96.7% correct assignments between MS and control groups) and was significantly correlated with reduction of white matter fractional anisotropy, as determined by diffusion tensor imaging and the Expanded Disability Status Scale. As expected by the predominant gray and WM degeneration in AD, no systematic curvature increase was observed in AD.

Conclusion: Whole-brain-averaged cortical extrinsic curvature appears to be a specific and quantitative marker for a WMV-cortex disproportionality and allows us to assess "pure" WMA without being confounded by intracranial volume. WMA seems to be a characteristic symptom in early MS and can already occur in patients with CIS and should thus be considered in future MS research and clinical studies.
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http://dx.doi.org/10.1016/j.nicl.2014.02.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4299934PMC
August 2015

A human post-mortem brain model for the standardization of multi-centre MRI studies.

Neuroimage 2015 Apr 14;110:11-21. Epub 2015 Jan 14.

Brain Imaging Center (BIC), Goethe University, Frankfurt am Main, Germany.

Multi-centre MRI studies of the brain are essential for enrolling large and diverse patient cohorts, as required for the investigation of heterogeneous neurological and psychiatric diseases. However, the multi-site comparison of standard MRI data sets that are weighted with respect to tissue parameters such as the relaxation times (T1, T2) and proton density (PD) may be problematic, as signal intensities and image contrasts depend on site-specific details such as the sequences used, imaging parameters, and sensitivity profiles of the radiofrequency (RF) coils. Water or gel phantoms are frequently used for long-term and/or inter-site quality assessment. However, these phantoms hardly mimic the structure, shape, size or tissue distribution of the human brain. The goals of this study were: (1) to validate the long-term stability of a human post-mortem brain phantom, performing quantitative mapping of T1, T2, and PD, and the magnetization transfer ratio (MTR) over a period of 18months; (2) to acquire and analyse data for this phantom and the brain of a healthy control (HC) in a multi-centre study for MRI protocol standardization in four centres, while conducting a voxel-wise as well as whole brain grey (GM) and white matter (WM) tissue volume comparison. MTR, T2, and the quotient of PD in WM and GM were stable in the post-mortem brain with no significant changes. T1 was found to decrease from 267/236ms (GM/WM) to 234/216ms between 5 and 17weeks post embedment, stabilizing during an 18-month period following the first scan at about 215/190ms. The volumetric measures, based on T1-weighted MP-RAGE images obtained at all participating centres, revealed inter- and intra-centre variations in the evaluated GM and WM volumes that displayed similar trends in both the post-mortem brain as well as the HC. At a confidence level of 95%, brain regions such as the brainstem, deep GM structures as well as boundaries between GM and WM tissues were found to be less reproducible than other brain regions in all participating centres. The results demonstrate that a post-mortem brain phantom may be used as a reliable tool for multi-centre MR studies.
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http://dx.doi.org/10.1016/j.neuroimage.2015.01.028DOI Listing
April 2015

Clinical relevance of specific T-cell activation in the blood and cerebrospinal fluid of patients with mild Alzheimer's disease.

Neurobiol Aging 2015 Jan 23;36(1):81-9. Epub 2014 Aug 23.

Department of Neurology, University Hospital Münster, Münster, Germany. Electronic address:

In Alzheimer's disease, the contribution of inflammation is still controversially discussed. The aim of this study was to identify a particular immune profile in the peripheral blood (PB) and cerebrospinal fluid (CSF) in patients with mild Alzheimer's disease (mAD) and mild cognitive impairment (MCI) and its potential functional relevance and association with neurodegeneration. A total of 88 patients with cognitive decline (54 mAD, 19 MCI, and 15 other dementias) were included in this study and compared with a group of younger (mean age, 31.3 years) and older (mean age, 68.9 years) healthy volunteers. Patients underwent detailed neurologic and neuropsychological examination, magnetic resonance imaging including voxel-based morphometry of gray matter, voxel-based diffusion tensor imaging, and white matter lesion volumetry, and PB and CSF analysis including multiparameter flow cytometry. Multiparameter flow cytometry revealed that proportions of activated HLA-DR positive CD4(+) and CD8(+) T-cells were slightly and significantly increased in the PB of MCI and mAD patients, respectively, when compared with healthy elderly controls but not in patients with other dementias. Although only a slight enhancement of the proportion of activated CD4(+) T-cells was observed in the CSF of both MCI and mAD patients, the proportion of activated CD8(+) T-cells was significantly increased in the CSF of mAD patients when compared with healthy elderly individuals. A slight increase in the proportion of activated CD8(+) T-cells was also observed in the intrathecal compartment of MCI patients. Activation of cytotoxic CD8(+) T-cells was considerably related to AD-typical neuropsychological deficits. Voxel-based regression analysis revealed a significant correlation between CD8(+) T-cell activation and microstructural tissue damage within parahippocampal areas as assessed by diffusion tensor imaging. Taken together, peripheral and intrathecal CD8(+) T-cell activation in mAD was significantly different from other dementias, suggesting a specific adaptive immune response. Lymphocyte activation seems to have a clinical impact because levels of activated CD8(+) T-cells were correlated with clinical and structural markers of AD pathology.
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http://dx.doi.org/10.1016/j.neurobiolaging.2014.08.008DOI Listing
January 2015

In vivo mapping of hippocampal subfields in mesial temporal lobe epilepsy: relation to histopathology.

Hum Brain Mapp 2014 Sep 17;35(9):4718-28. Epub 2014 Mar 17.

Department of Epileptology, University of Bonn, Bonn, Germany; Department of NeuroCognition/Imaging, Life & Brain Research Center, Bonn, Germany.

A particularly popular automated magnetic resonance imaging (MRI) hippocampal subfield mapping technique is the one described by Van Leemput et al. (2009: Hippocampus 19:549-557) that is currently distributed with FreeSurfer software. This method assesses the probabilistic locations of subfields based on a priori knowledge of subfield topology determined from high-field MRI. Many studies have applied this technique to conventionally acquired T1-weighted MRI data. In the present study, we investigated the relationship between this technique applied to conventional T1-weighted MRI data acquired at 3 T and postsurgical hippocampal histology in patients with medically intractable mesial temporal lobe epilepsy (mTLE) and hippocampal sclerosis (HS). Patients with mTLE (n = 82) exhibited significant volume loss of ipsilateral CA1, CA2-3, CA4-dentate gyrus (DG), subiculum, and fimbria relative to controls (n = 81). Histopathological analysis indicated that the most significant neuronal loss was observed in CA1, then CA4 and CA3, and more subtle neuronal loss in CA2, consistent with classical HS. Neuronal density of CA1 significantly correlated with MRI-determined volume of CA1, and increasingly so with CA2-3 and CA4-DG. Patients with increased HS based on histopathology had greater volume loss of the ipsilateral hippocampal regions on MRI. We conclude by suggesting that whilst time efficient and fully reproducible when applied to conventional single acquisition sequences, the use of the automated subfield technique described here may necessitate the application to multiacquisition high-resolution MR sequences for accurate delineation of hippocampal subfields.
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http://dx.doi.org/10.1002/hbm.22506DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6869541PMC
September 2014

Early detection of widespread progressive brain injury after cardiac arrest: a single case DTI and post-mortem histology study.

PLoS One 2014 14;9(3):e92103. Epub 2014 Mar 14.

Department of Neurology, University of Münster, Münster, Germany.

Objective: We tested the hypothesis in sense of a proof of principle that white matter (WM) degeneration after cardiopulmonary arrest (CPA) can be assessed much earlier by diffusion tensor imaging (DTI) than by conventional MRI.

Methods: We performed DTI and T2-weighted FLAIR imaging over four serial acquisitions of a 76-year-old man with unresponsive wakefulness syndrome at day 41, 75, 173 and 284 after CPA. DTI was also performed in ten healthy control subjects. Fractional anisotropy (FA) derived from DTI was assessed in eleven regions of interest within the cerebral white matter (WM) and compared with post-mortem neuropathological findings.

Results: In contrast to conventional FLAIR images that revealed only circumscribed WM damage, the first DTI demonstrated significant reduction of FA across the whole WM. The following FLAIR images (MRI 2-4) revealed increasing atrophy and leukoaraiosis paralleled by clinical deterioration with reduction of wakefulness and intractable seizures. Neuropathological findings confirmed the widespread and marked brain injury following CPA.

Conclusion: DTI may help to evaluate microstructural brain damage following CPA and may have predictive value for further evolution of cerebral degeneration in the chronic phase after CPA.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0092103PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3954875PMC
November 2014

DTI detects water diffusion abnormalities in the thalamus that correlate with an extremity pain episode in a patient with multiple sclerosis.

Neuroimage Clin 2013 28;2:258-62. Epub 2013 Jan 28.

Department of Neurology, Westfälische Wilhelms University, Münster, Germany.

Background: Various types of multiple sclerosis (MS) related pain have been discussed. One concept is that deafferentation secondary to lesions in the spino-thalamo-cortical network can cause central pain. However, this hypothesis is somehow limited by a lack of a robust association between pain episodes and sites of lesion location.

Objective: We tested the hypothesis that temporary tissue alterations in the thalamus that are not detectable by conventional magnetic resonance imaging (T1w, FLAIR) can potentially explain a focal, paroxysmal central pain episode of a patient with MS. For microstructural tissue assessment we employed ten longitudinal diffusion tensor imaging (DTI) examinations.

Results: We could demonstrate an abnormal, unilateral temporary increase of the fractional anisotropy (FA) in the thalamus contralateral to the affected body side. Before the pain episode and after pain relief the FA reached completely normal values as seen in identically investigated age and gender matched 100 healthy control subjects.

Conclusion: THESE FINDINGS SUGGEST THAT: i.) frequently applied and quantitatively evaluated DTI could be used as a sensitive imaging technique for detection of pathological processes associated with MS not detectable with conventional imaging strategies, ii.) temporary pathological processes in the "normal-appearing" thalamus may explain waxing and waning symptoms like episodes of central pain, and iii.) cross-sectional case examinations on (MS) patients with central pain should be performed to investigate how often thalamic alterations occur together with central pain.
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http://dx.doi.org/10.1016/j.nicl.2013.01.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3778262PMC
November 2013

Brainstem involvement as a cause of central sleep apnea: pattern of microstructural cerebral damage in patients with cerebral microangiopathy.

PLoS One 2013 23;8(4):e60304. Epub 2013 Apr 23.

Department of Neurology, University Hospital of Muenster, Muenster, Germany.

Background: The exact underlying pathomechanism of central sleep apnea with Cheyne-Stokes respiration (CSA-CSR) is still unclear. Recent studies have demonstrated an association between cerebral white matter changes and CSA. A dysfunction of central respiratory control centers in the brainstem was suggested by some authors. Novel MR-imaging analysis tools now allow far more subtle assessment of microstructural cerebral changes. The aim of this study was to investigate whether and what severity of subtle structural cerebral changes could lead to CSA-CSR, and whether there is a specific pattern of neurodegenerative changes that cause CSR. Therefore, we examined patients with Fabry disease (FD), an inherited, lysosomal storage disease. White matter lesions are early and frequent findings in FD. Thus, FD can serve as a "model disease" of cerebral microangiopathy to study in more detail the impact of cerebral lesions on central sleep apnea.

Patients And Methods: Genetically proven FD patients (n = 23) and age-matched healthy controls (n = 44) underwent a cardio-respiratory polysomnography and brain MRI at 3.0 Tesla. We applied different MR-imaging techniques, ranging from semiquantitative measurement of white matter lesion (WML) volumes and automated calculation of brain tissue volumes to VBM of gray matter and voxel-based diffusion tensor imaging (DTI) analysis.

Results: In 5 of 23 Fabry patients (22%) CSA-CSR was detected. Voxel-based DTI analysis revealed widespread structural changes in FD patients when compared to the healthy controls. When calculated as a separate group, DTI changes of CSA-CSR patients were most prominent in the brainstem. Voxel-based regression analysis revealed a significant association between CSR severity and microstructural DTI changes within the brainstem.

Conclusion: Subtle microstructural changes in the brainstem might be a neuroanatomical correlate of CSA-CSR in patients at risk of WML. DTI is more sensitive and specific than conventional structural MRI and other advanced MR analyses tools in demonstrating these abnormalities.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0060304PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3634049PMC
November 2013

Concomitant fractional anisotropy and volumetric abnormalities in temporal lobe epilepsy: cross-sectional evidence for progressive neurologic injury.

PLoS One 2012 11;7(10):e46791. Epub 2012 Oct 11.

Department of Neurology, University of Münster, Münster, Germany ; Department of Clinical Neuroscience, Institute of Psychiatry, King's College London, London, United Kingdom.

Background: In patients with temporal lobe epilepsy and associated hippocampal sclerosis (TLEhs) there are brain abnormalities extending beyond the presumed epileptogenic zone as revealed separately in conventional magnetic resonance imaging (MRI) and MR diffusion tensor imaging (DTI) studies. However, little is known about the relation between macroscopic atrophy (revealed by volumetric MRI) and microstructural degeneration (inferred by DTI).

Methodology/principal Findings: For 62 patients with unilateral TLEhs and 68 healthy controls, we determined volumes and mean fractional anisotropy (FA) of ipsilateral and contralateral brain structures from T1-weighted and DTI data, respectively. We report significant volume atrophy and FA alterations of temporal lobe, subcortical and callosal regions, which were more diffuse and bilateral in patients with left TLEhs relative to right TLEhs. We observed significant relationships between volume loss and mean FA, particularly of the thalamus and putamen bilaterally. When corrected for age, duration of epilepsy was significantly correlated with FA loss of an anatomically plausible route - including ipsilateral parahippocampal gyrus and temporal lobe white matter, the thalamus bilaterally, and posterior regions of the corpus callosum that contain temporal lobe fibres - that may be suggestive of progressive brain degeneration in response to recurrent seizures.

Conclusions/significance: Chronic TLEhs is associated with interrelated DTI-derived and volume-derived brain degenerative abnormalities that are influenced by the duration of the disorder and the side of seizure onset. This work confirms previously contradictory findings by employing multi-modal imaging techniques in parallel in a large sample of patients.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0046791PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3469561PMC
April 2013

Executive performance is related to regional gray matter volume in healthy older individuals.

Hum Brain Mapp 2013 Dec 19;34(12):3333-46. Epub 2012 Jul 19.

Department of Neurology, University Hospital of Münster, Münster, Germany; Department of Neurology, University of München, München, Germany.

Individual differences in executive functioning and brain morphology are considerable. In this study, we investigated their interrelation in a large sample of healthy older individuals. Digit span, trail-making, and Stroop tasks were used to assess different executive subfunctions in 367 nondemented community-dwelling individuals (50-81 years). Task performance was analyzed relative to brain structure using voxel-based morphometry, corrected for age and sex. Improved task performance was associated with increased local gray matter volume in task-specific patterns that showed partial, but not complete overlap with known task-specific functional imaging patterns. While all three tasks showed associations with prefrontal gray matter volume as expected for executive functioning, the strongest overlap between the three tasks was found in insular cortex, suggesting that it has a previously underestimated role for executive functions. The association between the insular cortex and executive functioning was corroborated using stereological region-of-interest measurement of insular volume in a subgroup of 93 subjects. Quantitatively, the volume of the single most strongly related region explained 2.4 ± 1.1% of the variance in executive performance over and above the variance explained by age, which amounted to 7.4 ± 4.1%. The age-independent peak associations between executive performance and gray matter described here occurred in regions that were also strongly affected by age-related gray matter atrophy, consistent with the hypothesis that age-related regional brain volume loss and age-related cognitive changes are linked.
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http://dx.doi.org/10.1002/hbm.22146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6869861PMC
December 2013

The influence of spatial registration on detection of cerebral asymmetries using voxel-based statistics of fractional anisotropy images and TBSS.

PLoS One 2012 5;7(6):e36851. Epub 2012 Jun 5.

Department of Neurology, University of Münster, Münster, Germany.

The sensitivity of diffusion tensor imaging (DTI) for detecting microstructural white matter alterations has motivated the application of voxel-based statistics (VBS) to fractional anisotropy (FA) images (FA-VBS). However, detected group differences may depend on the spatial registration method used. The objective of this study was to investigate the influence of spatial registration on detecting cerebral asymmetries in FA-VBS analyses with reference to data obtained using Tract-Based Spatial Statistics (TBSS). In the first part of this study we performed FA-VBS analyses using three single-contrast and one multi-contrast registration: (i) whole-brain registration based on T2 contrast, (ii) whole-brain registration based on FA contrast, (iii) individual-hemisphere registration based on FA contrast, and (iv) a combination of (i) and (iii). We then compared the FA-VBS results with those obtained from TBSS. We found that the FA-VBS results depended strongly on the employed registration approach, with the best correspondence between FA-VBS and TBSS results when approach (iv), the "multi-contrast individual-hemisphere" method was employed. In the second part of the study, we investigated the spatial distribution of residual misregistration for each registration approach and the effect on FA-VBS results. For the FA-VBS analyses using the three single-contrast registration methods, we identified FA asymmetries that were (a) located in regions prone to misregistrations, (b) not detected by TBSS, and (c) specific to the applied registration approach. These asymmetries were considered candidates for apparent FA asymmetries due to systematic misregistrations associated with the FA-VBS approach. Finally, we demonstrated that the "multi-contrast individual-hemisphere" approach showed the least residual spatial misregistrations and thus might be most appropriate for cerebral FA-VBS analyses.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0036851PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3367973PMC
October 2012

Early microstructural white matter changes in patients with HIV: a diffusion tensor imaging study.

BMC Neurol 2012 May 1;12:23. Epub 2012 May 1.

Department of Neurology, University of M uumlnster, Albert-Schweitzer-Campus, Germany.

Background: Previous studies have reported white matter (WM) brain alterations in asymptomatic patients with human immunodeficiency virus (HIV).

Methods: We compared diffusion tensor imaging (DTI) derived WM fractional anisotropy (FA) between HIV-patients with and without mild macroscopic brain lesions determined using standard magnetic resonance imaging (MRI). We furthermore investigated whether WM alterations co-occurred with neurocognitive deficits and depression. We performed structural MRI and DTI for 19 patients and 19 age-matched healthy controls. Regionally-specific WM integrity was investigated using voxel-based statistics of whole-brain FA maps and region-of-interest analysis. Each patient underwent laboratory and neuropsychological tests.

Results: Structural MRI revealed no lesions in twelve (HIV-MRN) and unspecific mild macrostructural lesions in seven patients (HIV-MRL). Both analyses revealed widespread FA-alterations in all patients. Patients with HIV-MRL had FA-alterations primarily adjacent to the observed lesions and, whilst reduced in extent, patients with HIV-MRN also exhibited FA-alterations in similar regions. Patients with evidence of depression showed FA-increase in the ventral tegmental area, pallidum and nucleus accumbens in both hemispheres, and patients with evidence of HIV-associated neurocognitive disorder showed widespread FA-reduction.

Conclusion: These results show that patients with HIV-MRN have evidence of FA-alterations in similar regions that are lesioned in HIV-MRL patients, suggesting common neuropathological processes. Furthermore, they suggest a biological rather than a reactive origin of depression in HIV-patients.
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http://dx.doi.org/10.1186/1471-2377-12-23DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3500236PMC
May 2012

Progression of microstructural putamen alterations in a case of symptomatic recurrent seizures using diffusion tensor imaging.

Seizure 2012 Jul 28;21(6):478-81. Epub 2012 Apr 28.

Department of Neurology, University of Münster, Germany.

Microstructural alterations of the putamen were recently reported in patients with partial and generalized epilepsy disorders. However, it is unknown whether these alterations pre-exist or are secondary to recurrent seizures. Here we investigated the progression of putamen fractional anisotropy (FA) alterations in a case of recurrent psychomotor seizures using longitudinal diffusion tensor imaging (DTI) shortly before (DTI-1) and after a psychomotor seizure (DTI-2). We obtained FA values of a hypothesis-guided putamen region-of-interest (ROI) and seven exploratory ROIs. FA values from both DTIs were compared with reference values from 19 controls. Relative to controls, the patient's putamen FA was increased at DTI-1 (13% left putamen, 7% right putamen), an effect that was exacerbated at DTI-2 (24% left putamen (p<0.05), 20% right putamen). In the exploratory ROIs we found FA reductions in the corticospinal tract, temporal lobe, and occipital lobe (p<0.05) relative to controls at DTI-1 and DTI-2. In contrast to the putamen, all exploratory ROIs showed no relevant FA change between DTI-1 and DTI-2. These results suggest that recurrent seizures may lead to progressive microstructural putamen alterations.
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http://dx.doi.org/10.1016/j.seizure.2012.03.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3778939PMC
July 2012

Methodological aspects of functional transcranial Doppler sonography and recommendations for simultaneous EEG recording.

Ultrasound Med Biol 2012 Jun 12;38(6):989-96. Epub 2012 Apr 12.

Department of Neurology, Justus-Liebig University, Giessen, Germany.

The neurovascular coupling describes a vasoregulative principle of the brain that adapts local cerebral blood flow in accordance with the underlying neuronal activity. It is the basis of modern indirect brain imaging techniques. Because of its wide availability and high tolerability the functional transcranial Doppler has been often used to assess brain function in clinical conditions. In the present paper we will give an overview of the current understanding of the coupling, explain basic principles of the Doppler technique and summarize relevant findings of functional Doppler tests in the different vascular territories of the brain. Finally, the concept of a combined functional electroencephalogram and transcranial Doppler technique will be outlined, which allows simultaneous investigation of the neuronal and vascular responses of neurovascular coupling.
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http://dx.doi.org/10.1016/j.ultrasmedbio.2012.02.027DOI Listing
June 2012

Volume estimation of the thalamus using freesurfer and stereology: consistency between methods.

Neuroinformatics 2012 Oct;10(4):341-50

Department of Neurology, University of Münster, Münster, Germany.

Freely available automated MR image analysis techniques are being increasingly used to investigate neuroanatomical abnormalities in patients with neurological disorders. It is important to assess the specificity and validity of automated measurements of structure volumes with respect to reliable manual methods that rely on human anatomical expertise. The thalamus is widely investigated in many neurological and neuropsychiatric disorders using MRI, but thalamic volumes are notoriously difficult to quantify given the poor between-tissue contrast at the thalamic gray-white matter interface. In the present study we investigated the reliability of automatically determined thalamic volume measurements obtained using FreeSurfer software with respect to a manual stereological technique on 3D T1-weighted MR images obtained from a 3 T MR system. Further to demonstrating impressive consistency between stereological and FreeSurfer volume estimates of the thalamus in healthy subjects and neurological patients, we demonstrate that the extent of agreeability between stereology and FreeSurfer is equal to the agreeability between two human anatomists estimating thalamic volume using stereological methods. Using patients with juvenile myoclonic epilepsy as a model for thalamic atrophy, we also show that both automated and manual methods provide very similar ratios of thalamic volume loss in patients. This work promotes the use of FreeSurfer for reliable estimation of global volume in healthy and diseased thalami.
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http://dx.doi.org/10.1007/s12021-012-9147-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3464372PMC
October 2012
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