On the effect of flow and modest diffusion weighting in fMRI
Hoogduin H, Versluis M
University Medical Center Groningen, University of Groningen
The effect of flow and modest diffusion weighting in fMRI is studied using a newly developed method which allows a cyclic variation of the amount of flow or diffusion weighting over the scanned volumes in a fast multi-echo SENSE EPI sequence. The multi-echo acquisition allows the creation of T2* and I0 maps. Results show that in the motor cortex I0 reduces and T2* increases upon execution of a motor task. The reduction in I0 is significantly larger when flow or diffusion weighting is applied while changes in T2* remain nearly constant. This indicates that the intravascular contribution to the BOLD effect at 3T is negligable.