Increased T2-sensitivity in BOLD fMRI using stimulated echoes: A Monte-Carlo simulation
Goerke U, Ugurbil K
CMRR/University of Minnesota
Monte-Carlo simulations were applied to calculate the relative BOLD signal changes in a stimulated echo sequence. The model was based on the diffusion of water molecules in the presence of local magnetic field variations in the vicinity of capillaries and venules. Neighboring vessels were included to account for long diffusion times. The predicted increase of the relative signal change with longer echo and mixing time is consistent with experimental results. It is concluded that more efficient dynamic averaging is the main mechanism for the enhanced T2-sensitivity of the STE.