Tao Jin1, Ping Wang1, Seong-Gi Kim1,2
1Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; 2Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
The diffusion weighted fMRI signal change has been found to increase at high b-values, indicating a decrease of the apparent diffusion coefficient (ADC). It is currently unclear whether this ADC decrease is predominately caused by vascular contributions. We have studied the diffusion-weighted fMRI in the cat visual cortex for high b-values (up to 2500s/mm2), with and without the suppression of intravascular blood using a contrast agent. We found that the diffusion fMRI signal after contrast agent injection increases with b-value at the parenchyma, indicating a small decrease of ADC in the extravascular space.