Tissue and vascular contributions to diffusion fMRI in rat inferior colliculus using quadratic exponential kurtosis model

Abstract

Under functional activation, both tissue and vasculature undergo physiological changes (such as cell swelling and vessel dilation). Non-diffusion-weighted BOLD and diffusion-weighted BOLD have been reported to reflect different tissue/vascular contribution when the strength of diffusion attenuation (b-value) is alternated. Different b-values signal fittings and kurtosis models are presented in this study to evaluate non-Gaussian distribution of diffusion displacement in brain tissue during activation. Kurtosis increased and was mainly contributed by the increase in blood flow during activation as indicated by the initial fast decay of diffusion signal.