Fiber tracking

Four views of fibers emanating from single voxel mid optic tract reveal connections to optic bulbs and retinal ganglia.

A multishell diffusion scheme was used, and the b-values were 600, 1200 and 1800 s/mm2. The number of diffusion sampling directions were 10, 19, and 29, respectively. The in-plane resolution was 0.25 mm. The slice thickness was 0.5 mm. The diffusion data were reconstructed using generalized q-sampling imaging (2) with a diffusion sampling length ratio of 1.8. The restricted diffusion was quantified using restricted diffusion imaging (3). A deterministic fiber tracking algorithm (4) was used. For fiber tracks,  the seeding region was placed at mid optic tract with a volume size of 0.031 mm cubic (a single voxel). The angular threshold was 60 degrees. The step size was 0.1 mm. The anisotropy threshold was 0.03875. The fiber trajectories were smoothed by averaging the propagation direction with 10% of the previous direction. Tracks with length shorter than 2 or longer than 30 mm were discarded. The analysis was conducted using DSI Studio (http://dsi-studio.labsolver.org).

  1. Caruyer E, Lenglet C, Sapiro G, Deriche R. Design of multishell sampling schemes with uniform coverage in diffusion MRI. Magn Reson Med. 2013;69(6):1534-40. Epub 2013/04/30. doi: 10.1002/mrm.24736. PubMed PMID: 23625329; PMCID: PMC5381389.
  2. Yeh FC, Wedeen VJ, Tseng WY. Generalized q-sampling imaging. IEEE Trans Med Imaging. 2010;29(9):1626-35. Epub 2010/03/23. doi: 10.1109/TMI.2010.2045126. PubMed PMID: 20304721.
  3. Yeh FC, Liu L, Hitchens TK, Wu YL. Mapping immune cell infiltration using restricted diffusion MRI. Magn Reson Med. 2017;77(2):603-12. Epub 2016/02/05. doi: 10.1002/mrm.26143. PubMed PMID: 26843524.
  4. Yeh F-C, Verstynen TD, Wang Y, Fernández-Miranda JC, Tseng W-YI. Deterministic Diffusion Fiber Tracking Improved by Quantitative Anisotropy. PLOS ONE. 2013;8(11):e80713. doi: 10.1371/journal.pone.0080713.