Marek Chmelk1,2, Wolfgang Bogner, 2,3, Stephan Gruber, 2,3, Siegfried Trattnig, 2,3, Martin Krk, 2,3
1Department of Radiology, Medical University of Vienna, Vienna, Austria; 2MR Centre of Excellence, Medical University of Vienna, Vienna, Austria; 3Department of Radiology, Medical University of Vienna, Vienna, Austria
It has been shown that in vivo muscle 31P T1 relaxation times decrease at higher magnetic field (7T) due to higher contribution of chemical shift anisotropy. The purpose of this study was to compare and optimize SNR-per-unit-time of 31P 3D MRSI in the human calf at 3T and 7T. Phantom experiments with comparable T1 times showed 94% increase of SNR-per-unit-time whereas in vivo muscle SNR-per-unit time was increased by 140%, partly due to shorter T1 relaxation. Both higher magnetic field and shorter T1 relaxation time contribute to improvement of 31P MRSI SNR-per-unit-time at 7T.