Peter Hallscheidt

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The present study proposes a catheter system with an expandable coil etched on a polyimide foil. The catheter system combines the advantages of a small insertion diameter when the coil is rolled up in a protective carrier sheath with an increased signal-to-noise ratio (SNR) and penetration depth when the coil is pushed out. After imaging, the coil can be(More)
In this work active MR catheter tracking with automatic slice alignment was combined with an autocalibrated parallel imaging technique. Using an optimized generalized autocalibrating partially parallel acquisitions (GRAPPA) algorithm with an acceleration factor of 2, we were able to reduce the acquisition time per image by 34%. To accelerate real-time(More)
High-frequency volumetric Power Doppler ultrasound (HF-VPDU) captures flow-dependent signals in blood vessels and can be used to assess antiangiogenic therapy effects in rodent tumors. However, the sensitivity is limited to vessels larger than capillaries. Contrast-enhanced HF-VPDU reveals all perfused vessels by assessing stimulated acoustic emissions from(More)
In active catheter tracking, small RF coils are attached to the catheter for localization. For interactive catheter steering at vessel branchings, it is necessary to visualize not only a single point near the catheter tip but also the entire shape and orientation of the catheter's distal end. Therefore, a 35-mm-long twisted-pair RF coil was added to a 5(More)
Flow measurements can be used to quantify blood flow during MR-guided intravascular interventional procedures. In this study, a fast flow measurement technique is proposed that quantifies flow velocities in the vicinity of a small RF coil attached to an intravascular catheter. Since the small RF coil receives signal from only a limited volume around the(More)
AIMS Measurements indicating a loss of integrity of the levator ani muscle, which is an integral part of the pelvic floor, have been subject of recent studies using translabial ultrasound and 3D-MRI-models. We transferred these measurements into 2D-3 T-MR-images for clinical routine, as it is objective and does not need exhaustive post-processing. METHODS(More)
We report a case of a woman with a gastrointestinal bleeding. An esophageal ulcer was detected in the endoscopy, however a histological malignancy could not be found. A computer tomography (CT) scan showed a thickness in the distal esophagus and enlarged lymph nodes, so a malignancy was highly suspected. However, the patient refused to follow the(More)
Magnetic resonance imaging (MRI) is ideally suited to monitor minimally invasive operations with catheters or needles, since it offers both a superior soft-tissue contrast and the possibility to perform functional tests. In the present study, small radio-frequency coils were attached to the instruments in order to localize the MR-invisible instruments. The(More)
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