Does the Signal Arising from a Single Fascicle Significantly Deviates from a Monoexponential Decay with a Clinical Scanner?

Benoit Scherrer¹, Maxime Taquet¹, ², Onur Afacan¹, Simon K. Warfield¹

Multiple works have shown that the diffusion attenuation in a voxel significantly deviates from a monoexponential decay. However, when imaging with a clinical scanner with long δ, it is not clear that the signal arising from a single fascicle is non-monoexponential. We hypothesize that the non-monoexponential behavior observed in voxels may reflect predominantly the presence of multiple fascicles with heterogeneous orientation and the presence of an additional compartment that is macroscopically isotropic. We imaged a region containing a single fascicle orientation, the body of the corpus and investigated the residual diffusion decay after subtracting the contribution of unrestricted diffusion.