Klaus Straubinger

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Proton-decoupled 31P NMR spectroscopy of the heart and calf muscle of healthy volunteers was performed with a 1.5 T whole-body imager. By use of two-dimensional chemical-shift imaging in combination with slice-selective excitation, well-resolved localized spectra (elements of 38 ml) were obtained within 20 to 35 min from which the homonuclear J coupling(More)
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;(More)
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(More)
T2 measurements of 31P NMR signals of ATP using the Hahn 90 degrees-180 degrees spin-echo sequence imply difficulties whenever the 180 degrees pulse angle is not completely perfect. The reason for this finding is the crucial influence of the J-couplings of the ATP signals which result in intensity modulations and consequently in false T2 values even when(More)
The time evolution of the density operator of an AB spin system during a double-spin-echo pulse sequence is evaluated analytically by a computer-algebra system. The computer-algebra system allows one to generate the extensive formulas describing the density operator and yields an expression for the integral of the spectral signals. The simulation of spectra(More)
Quantification of citrate by localized 1H spectroscopy is usually performed using the water signal as reference, but the signal behavior of the J-coupled AB spin system of citrate after multipulse excitation is not as trivial as for uncoupled substances. The influence of the timing scheme of double spin-echo sequences and of the spatial flip angle(More)
The influence of pulse angle variations in the localization sequence stimulated echo acquisition mode (STEAM) on the signal of strongly coupled AB spin systems has been examined. Experimental1H nuclear magnetic resonance (NMR) spectra of citrate were recorded on a 1.5 T whole-body imager. Theoretically calculated spectra were generated, with good(More)
31P magnetic resonance spectroscopy (MRS) examinations of the calf muscles of healthy volunteers were performed to determine T2 of the coupled ATP signals by use of the Hahn spin-echo and the frequency-selective spin-echo method. Additional measurements with the J-coupling refocused double echo are presented. The most reliable determination of T2 relaxation(More)
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