Biomedical subjects
Publications and source records attributed to M Bunse.
31P MRS examinations of the brain of 10 healthy volunteers were performed to determine T2 of the coupled ATP signals by use of the localized 90 degrees-TE/2-2662-TE/2-acq frequency selective spin echo sequence for elimination of phase and intensity distortions. The T2 relaxation times obtained are much longer than usually assumed: gamma-ATP: 89 +/- 9 ms; alpha-ATP: 84 +/- 6 ms; beta-ATP: 62 +/- 3 ms.
Using a flow-rephased spin-echo technique with a short echo time of TE = 9.7 msec, "white blood" multislice and single slice first echo images of the human heart were acquired using standard 1.5 T whole-body imagers. The technique almost completely eliminates phase shifts for flow with constant velocity and constant acceleration, so the investigations with healthy volunteers show images which are almost free of the artifacts often found in ECG-gated standard spin-echo imaging of the heart. T1-weighted images with good contrast between tissue and blood are achieved at any time during the whole heart cycle. The results obtained indicate that the technique might be helpful for imaging small vessels, vessels which contain slowly flowing blood, and vessels located in regions with static field inhomogeneities, for example, lung vessels.
31P MRS examinations of the calf muscles of 12 healthy volunteers were performed to determine T2 of the coupled ATP signals by using the 90 degrees-TE/2-2662-TE/2-acq selective spin-echo sequence for elimination of phase and intensity distortions. The T2 relaxation times obtained are much longer than those usually assumed: gamma-ATP, 93 ms; alpha-ATP, 74 ms; beta-ATP, 75 ms.
The FID, DRESS, CRISIS/CODEX, and STEAM techniques for localized 31P NMR spectroscopy were compared using a Siemens Magnetom SP63 1.5 T whole-body imager and a surface-coil, 80 mm in diameter, acting as transmitter and receiver coil. The comparison was performed with phantom experiments and human in vivo investigations on the calf muscle. The phantom experiments which used the same volume size showed a comparable signal-to-noise ratio for FID and DRESS, while the two fully localized techniques showed a reduction in signal-to-noise ratio to 76% for CRISIS/CODEX and 31% for STEAM. The in vivo measurements confirm the phantom results and reveal that CRISIS/CODEX gains a 2.5 fold higher signal-to-noise ratio than STEAM under the same conditions.