Stephan Witoszynskyj

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We present a fully automated phase unwrapping algorithm (Phi UN) which is optimized for high-resolution magnetic resonance imaging data. The algorithm is a region growing method and uses separate quality maps for seed finding and unwrapping which are retrieved from the full complex information of the data. We compared our algorithm with an established(More)
Susceptibility-weighted MR imaging (SWI) has become a non-invasive diagnostic modality for functional MR imaging (fMRI) of the brain and also for the imaging of tumors, injuries, malformations or microhemorrhages. SWI often enables detection of otherwise subtle abnormalities or provides additional relevant information when combined with routine MR imaging.(More)
A method is presented for the combination of phase images from multi-channel RF coils in the absence of a volume reference coil. It is based on the subtraction of 3D phase offset maps from the phase data from each coil. Phase offset maps are weighted combinations of phase measurements at two echo times. Multi-Channel Phase Combination using measured 3D(More)
We present numerical simulations and experimental results for susceptibility weighted imaging (SWI) at 7 T. Magnitude, phase, and SWI contrast were simulated for different voxel geometries and imaging parameters, resulting in an echo time of 14 msec for optimum contrast between veins and surrounding tissue. Slice thickness of twice the in-plane voxel size(More)
Susceptibility-weighted (SW) magnetic resonance (MR) imaging provides high-resolution, distortion-free blood oxygen level-dependent (BOLD) data for assessment of cerebral veins, blood products, and brain lesions. Currently, reconstruction of SW imaging data is not implemented on all MR imaging systems or is restricted in terms of parameter adjustments. New(More)
Susceptibility weighted imaging (SWI) combines magnitude and phase information from a high-resolution, fully velocity compensated, three-dimensional (3D) gradient echo sequence. We report on the use of this MRI technique in a young patient with acute lymphocytic leukemia (ALL) and demonstrate a higher detection rate of hemorrhagic lesion in comparison with(More)
Einleitung In den letzten Jahren hat sich die BOLD-MR-Venographie [1] (auch suszeptibilitätsgewichtete Bildgebung, kurz SWI genannt) immer mehr etablieren können und wird zur Untersuchung von Tumoren [2,3], aber auch zur Untersuchung physiologischer Vorgänge verwendet [4]. Zur Generierung von BOLD Venogrammen wird Phasen-und Magnitudeninformation, beginnend(More)
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