Diffusion tensor fiber tractography of the olfactory tract.

Magnetic resonance diffusion tensor imaging with fiber tracking is used for 3-dimensional visualization of the nervous system. Peripheral nerves and all cranial nerves, except for the olfactory tract, have previously been visualized. The olfactory tracts are difficult to depict with diffusion-weighted imaging due to the high sensitivity to susceptibility artifacts at the base of the skull. Here we report an optimized single-shot diffusion-weighted echo planar imaging sequence that can visualize the olfactory tracts with fiber tracking. Five healthy individuals were examined, and the olfactory tracts could be fiber tracked with the diffusion-weighted sequence. For comparison and as a negative control, an anosmic patient was examined. No olfactory tracts were visualized on T2-weighted nor diffusion-weighted fiber tracking images. Measuring diffusion in the olfactory tracts promise to facilitate the identification of different hyposmic and anosmic conditions.