Using Track Similarity to Determine Optimum Sequence Parameters for Diffusion Spectrum Imaging

For clinical diffusion spectrum imaging (DSI), fewer diffusion-encoding gradients and lower maximal diffusion-encoding sensitivity (bmax) are needed to reduce scan time and keep the hardware stable. However, aliasing or truncation artifact may become prominent when 3D Fourier transform of the q-space spectral data is performed. The purpose of this study was to determine the optimum sampling scheme for clinical DSI. We used 925 encoding gradients with bmax = 9000 s/mm 2 as the gold standard. Similarity of tractography generated from different sampling schemes to the tractography generated from the gold standard was compared. Using 515 diffusion-encoding gradients and bmax = 6000 s/mm 2 was considered to be the optimum condition for clinical DSI