Comparison Between Kurtosis and Biexponential Models for Diffusion-Weighted Brain Imaging with High Resolution and High B-Factor

Bibek Dhital¹, Robert Turner¹

B-factors greater than 2000 s.mm^-2 are rarely used in diffusion-weighted imaging, due to the consequent loss of adequate SNR. Early studies at high b-factor used biexponential fitting, but recently its appropriateness for human brain imaging has been questioned, and kurtosis analysis has been proposed as an alternative with fewer fit parameters. Benefitting from the high SNR of diffusion-weighted STEAM-EPI at 7T, we acquired diffusion-weighted images with a resolution of 2 mm isotropic and maximum b-value of 8000 s.mm^-2 . Comparing biexponential fits to kurtosis fits for each voxel, we found that biexponential fits showed much superior goodness-of-fit throughout the brain.