Fig 6. The graphs show the results of the simulation study in which 1 (A) or 2 (B) of the 3 fiber bundles contained within a nonisotropic voxel were rotated 180°.

A, When only 1 of the fiber bundles was rotated from its original location, FA underestimation occurred, which was lowest when the fiber bundle was oriented perpendicular (90°) to its original location.

B, Similarly, when 2 of 3 fiber bundles were rotated simultaneously, FA was underestimated to various degrees depending on the extent of the rotation, becoming zero when both bundles were perpendicular to each other (represented by the central part of this 3D graph).