Till-Karsten Hauser

YNICL Journal 2019 Journal Article

Hypercapnic BOLD MRI compared to H215O PET/CT for the hemodynamic evaluation of patients with Moyamoya Disease

• Till-Karsten Hauser
• Achim Seeger
• Benjamin Bender
• Uwe Klose
• Johannes Thurow
• Ulrike Ernemann
• Marcos Tatagiba
• Philipp T. Meyer

BACKGROUND AND PURPOSE: O PET/CT with ACZ challenge to assess comparability between both modalities. METHODS: O PET/CT with ACZ challenge in patients with angiographically proven MMD. Images of both modalities were analyzed retrospectively in a blinded, standardized fashion by visual inspection, as well as with a semi-quantitative analysis using stimuli-induced approximated regional perfusion-weighted data and BOLD-signal changes with reference to cerebellum. RESULTS: 20 consecutive patients fulfilled the inclusion criteria, a total of 160 vascular territories were analyzed retrospectively. Visual analysis (4-step visual rating system) of standardized, color-coded cerebrovascular reserve/reactivity maps showed a very strong correlation (Spearman's rho = 0.9, P < 0.001) between both modalities. Likewise, comparison of approximated regional perfusion changes across vascular territories (normalized to cerebellar change) reveal a highly significant correlation between both methods (Pearson's r = 0.71, P < 0.001). CONCLUSIONS: O PET/CT with ACZ challenge. It therefore holds future potential in becoming a routine examination in the pre- and postoperative evaluation of MMD patients after further prospective evaluation.

YNIMG Journal 2012 Journal Article

Functional MRI-guided probabilistic tractography of cortico-cortical and cortico-subcortical language networks in children

• Philip Julian Broser
• Samuel Groeschel
• Till-Karsten Hauser
• Karen Lidzba
• Marko Wilke

In this study, we analyzed the structural connectivity of cortico-cortical and cortico-subcortical language networks in healthy children, using probabilistic tractography based on high angular resolution diffusion imaging. In addition to anatomically defining seed and target regions for tractography, we used fMRI to target inferior frontal and superior temporal cortical language areas on an individual basis. Further, connectivity between these cortical and subcortical (thalamus, caudate nucleus) language regions was assessed. Overall, data from 15 children (8f) aged 8–17years (mean age 12. 1±3years) could be included. A slight but non-significant trend towards leftward lateralization was found in the arcuate fasciculus/superior longitudinal fasciculus (AF/SLF) using anatomically defined masks (p >. 05, Wilcoxon rank test), while the functionally-guided tractography showed a significant lateralization to the left (p <. 01). Connectivity of the thalamus with language regions was strong but not lateralized. Connectivity of the caudate nucleus with inferior-frontal language regions was also symmetrical, while connectivity with superior-temporal language regions was strongly lateralized to the left (p <. 01). To conclude, we could show that tracking the arcuate fasciculus/superior longitudinal fasciculus is possible using both anatomically and functionally-defined seed and target regions. With the latter approach, we could confirm the presence of structurally-lateralized cortico-cortical language networks already in children, and finally, we could demonstrate a strongly asymmetrical connectivity of the caudate nucleus with superior temporal language regions. Further research is necessary in order to assess the usability of such an approach to assess language dominance in children unable to participate in an active fMRI study.

YNIMG Journal 2011 Journal Article

Assessing language and visuospatial functions with one task: A “dual use” approach to performing fMRI in children

• Kathina Ebner
• Karen Lidzba
• Till-Karsten Hauser
• Marko Wilke

In order to increase the rate of successful functional MR studies in children it is helpful to shorten the time spent in the scanner. To this effect, assessing two cognitive functions with one task seems to be a promising approach. The hypothesis of this study was that the control condition of an established language task (vowel identification task, VIT) requires visuospatial processing and that the control condition (VITCC) therefore may also be applicable to localize visuospatial functions. As a reference task, a visual search task (VST, previously established for use in children) was employed. To test this hypothesis, 43 children (19 f, 24 m; 12. 0±2. 6, range 7. 9 to 17. 8years) were recruited and scanned using both tasks. Second-level random effects group analyses showed activation of left inferior-frontal cortex in the active condition of the VIT, as in previous studies. Additionally, analysis of the VITCC demonstrated activation in right-dominant superior parietal and high-frontal brain regions, classically associated with visuospatial functions; activation seen in the VST was similar with a substantial overlap. However, lateralization in the parietal lobe was significantly more bilateral in the VST than in the VITCC. This suggests that the VIT can not only be applied to assess language functions (using the active>control contrast), but also that the control>active condition is useful for assessing visuospatial functions. Future task design may benefit from such a “dual use” approach to performing fMRI not only, but also particularly in children.

YNIMG Journal 2010 Journal Article

Corrigendum to “Visualization, quantification and correlation of brain atrophy with clinical symptoms in spinocerebellar ataxia types 1, 3 and 6” [NeuroImage 49 (2010) 158–168]

• Jörg B. Schulz
• Johannes Borkert
• Stefanie Wolf
• Tanja Schmitz-Hübsch
• Maryla Rakowicz
• Caterina Mariotti
• Ludger Schöls
• Dagmar Timmann

YNIMG Journal 2010 Journal Article

Visualization, quantification and correlation of brain atrophy with clinical symptoms in spinocerebellar ataxia types 1, 3 and 6

• Jörg B. Schulz
• Johannes Borkert
• Stefanie Wolf
• Tanja Schmitz-Hübsch
• Maryla Rakowicz
• Caterina Mariotti
• Ludger Schoels
• Dagmar Timmann

Background and objective Biomarkers to monitor neurological dysfunction in autosomal dominant inherited spinocerebellar ataxias (SCA) are lacking. We therefore aimed to visualize, quantify and correlate localized brain atrophy with clinical symptoms in SCA1, SCA3, and SCA6. Methods We compared patients suffering from SCA1 (n =48), SCA3 (n =24), and SCA6 (n =10) with 32 controls using magnetic resonance imaging (MRI) on four different scanners in eight centers followed by voxel-based morphometry (VBM) and quantitative three-dimensional (3D) volumetry. Results SCA1 and SCA3 patients presented with severe atrophy in total brainstem (consisting of midbrain, pons, and medulla), pons, medulla, total cerebellum, cerebellar hemispheres and cerebellar vermis, putamen and caudate nucleus. Atrophy in the cerebellar hemispheres was less severe in SCA3 than in SCA1 and SCA6. Atrophy in SCA6 was restricted to the grey matter of the cerebellum (VBM and volumetry), total brainstem and pons (volumetry only). Overall, we did not observe substantial atrophy in the cerebral cortex. A discriminant analysis taking into account data from pons, cerebellar hemispheres, medulla, midbrain and putamen achieved a reclassification probability of 81. 7% for SCA1, SCA3, and SCA6. The repeat length of the expanded allele showed a weak negative correlation with the volume of the brainstem, pons, caudate nucleus and putamen in SCA3, and a weak correlation with the pons in SCA1, whereas no such correlation was found in SCA6. Clinical dysfunction as measured by the Scale for the Assessment and Rating of Ataxia (SARA) and the Unified Huntington's Disease Rating Scale functional assessment correlated best with the atrophy of pons in SCA1, with total brainstem atrophy in SCA3 and atrophy of total cerebellum in SCA6. Conclusions Our data provide strong evidence that MRI is an attractive surrogate marker for clinical studies of SCA. In each SCA genotype clinical dysfunction may be caused by different patho-anatomical processes.

YNIMG Journal 2004 Journal Article

Magnetic resonance imaging-based volumetry differentiates progressive supranuclear palsy from corticobasal degeneration

• Klaus Gröschel
• Till-Karsten Hauser
• Andreas Luft
• Nicholas Patronas
• Johannes Dichgans
• Irene Litvan
• Jörg B Schulz

Because there are no biological markers for the clinical diagnosis of progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), we established a mathematical model based on three-dimensional magnetic resonance (MR) imaging to differentiate between these parkinsonian disorders. Using MR imaging-based volumetry we studied the pattern of atrophic changes in patients with probable, possible or definite PSP (n = 33) or CBD (n = 18). Patients were compared with 22 controls with similar age. To establish a mathematical model that would allow for differentiation of PSP, CBD and controls we performed a discriminant analysis. We found a significant reduction in average brain, brainstem, midbrain and frontal gray matter volumes in patients with PSP, whereas patients with CBD showed atrophy of parietal cortex and corpus callosum. With the exception of reduced midbrain volumes in PSP, the measured volumes of anatomical structures showed an extensive overlap with the normal range on an individual basis. Using only post mortem confirmed cases of PSP (n = 8) and CBD (n = 7) as well as all controls, the volumes of midbrain, parietal white matter, temporal gray matter, brainstem, frontal white matter and pons were identified to separate best between groups and were used to construct a model with two canonical variables. This model allowed to correctly predict the diagnosis in 95% of controls as well as in 76% of all PSP and 83% of all CBD patients. Similar results were obtained only when patients with a possible and probable diagnosis of PSP and CBD, who were not involved in the development of the discriminant analysis, were classified. 3D-MR imaging-based volumetry may help to differentiate PSP from CBD ante mortem.