Catalina S. Arteaga de Castro1, Alex Bhogal1, Mariska P. Luttje1, Marco van Vulpen1, Juus Noteboom1, Peter R. Luijten1, Uulke A. van der Heide2, Dennis W.J. Klomp1
1University Medical Center Utrecht, Utrecht, Netherlands; 2Netherlands Cancer Institute, Amsterdam, Netherlands
Variations of the main magnetic field can cause linewidth broadening and signal loss in long (8-10 min) MRSI experiments. In prostate MRSI a strongly coupled spin system (citrate) is observed. This spin system is sensitive to field variations, which can change the appearance of its peaks. Dynamic main field variations are observed in the prostate that exceed 15 Hz. These cause temporal susceptibility changes that explain the deteriorated spectrum. Second order B0 dynamic shimming simulations showed a gain of more than 10 Hz after correction of the B0 variations. Dynamic shimming can be implemented using localized navigators or field probes.