Fig.7.

Comparisons of diffusion tractography on the pyramidal tracts using different reconstruction methods. A seed was placed in the corticospinal tracts at the level of pons. Then, waypoint masks at the posterior limb of the internal capsule were used to restrain the tracts. 10,000 streamline samples were sent from the seed voxel and the results were normalized using the total number of streamlines that were not rejected by the mid-sagittal exclusion mask in the ground truth. Then, the normalized tracts were thresholded at 0.5% and MIP images on the sagittal plane were plotted and compared. It can be seen that FFT 50% and PCLR50% generated most accurate results when compared to the ground truth. At the undersampling rate of 25%, GP-PCLR is the only method that enables a faithful reconstruction of the main course of the pyramidal tracts. In contrast, the tracts reconstructed by FFT25% and PCLR25% were significantly deviated from the original course, generating false connections to the prefrontal cortex and the cerebellum.