Signal Source in Heavily Diffusion-Weighted functional MRI

The contribution of the BOLD effect in heavily diffusion weighted fMRI is still unclear. In this study, a multiple spin-echo echo-planar-imaging sequence after motion probing gradients was used to measure the transverse relaxation rate at different b-values. The results suggest that the contribution of BOLD to DW fMRI signal changes is independent of b-value. It is speculated that the main contribution to heavily diffusion-weighted functional MRI signal is not the BOLD effect.17th Scientific Meeting & Exhibitio