Fiber Tracking—We Should Move Beyond Diffusion Tensor Imaging

Abstract

n recent years the clinical application of diffusion tensor imaging (DTI) has attracted much interest in neurosurgery. I DTI is based on measuringmultiplediffusionweighted images in different gradient directions to resolve the orientation of white matter tracts. DTI provides information about the course, the displacement, or interruption ofwhitematter tracts around a tumor, as well as a widening of fiber bundles due to edema or tumor infiltration. Isotropic diffusion can be represented as a sphere,whereas anisotropic diffusion is expressed as an ellipsoid, with the water molecules moving along the long axis of a fiber bundle and less movement perpendicularly. Fiber tracking is probably the most clinically appealing and understandable technique for representing major white matter tracts. Various tracking algorithms, which compare local tensor field orientationsmeasured by DTI from voxel to voxel, have been developed, allowing a noninvasive tracing of large fiber tract bundles in the human brain.