AUTHOR=Dauleac Corentin , Frindel Carole , Pélissou-Guyotat Isabelle , Nicolas Célia , Yeh Fang-Cheng , Fernandez-Miranda Juan , Cotton François , Jacquesson Timothée 

TITLE=Full cervical cord tractography: A new method for clinical use

JOURNAL=Frontiers in Neuroanatomy

VOLUME=Volume 16 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/neuroanatomy/articles/10.3389/fnana.2022.993464

DOI=10.3389/fnana.2022.993464

ISSN=1662-5129

ABSTRACT=Despite recent improvements in diffusion-weighted imaging, spinal cord tractography is not used in routine clinical practice because of difficulties in reconstructing tractograms, with a pertinent tri-dimensional-rendering, in a long post-processing time. We propose a new full tractography approach of the cervical spinal cord without extensive manual filtering or multiple regions of interest seeding that could help neurosurgeons manage various spinal cord disorders.
Four healthy volunteers and 2 patients with either cervical intramedullary tumor or spinal cord injury were included. Diffusion-weighted images of the cervical spinal cord were acquired using a Philips 3 Tesla machine, 32 diffusion directions, 1000 sec/mm2 b-value, 2×2×2 mm voxel size, reduced field-of-view (ZOOM), with 2 opposed phase-encoding directions. Distortion corrections were then achieve using FSL software package, and tracking of the full cervical spinal cord was performed using DSI Studio software (quantitative anisotropy-based deterministic algorithm). A unique region of avoidance was used, in order to exclude everything that is not of the nervous system. Fiber tracking parameters used adaptative fractional anisotropy from 0.015 to 0.045, fiber length from 10 to 1000 mm, angular threshold: 90°.
In all participants, a full cervical cord tractography was performed from the medulla to the C7 spine level. On a ventral view, the junction between the medulla and spinal cord was identified with its pyramidal bulging, and by an invagination corresponding to the median ventral sulcus. On a dorsal view, the fourth ventricle – superior, middle and inferior cerebellar peduncles – was seen, as well as its floor and the obex; and gracile and cuneate tracts were recognize on each side of the dorsal median sulcus.  In case of the intramedullary tumor or spinal cord injury, the spinal tracts were seen to be displaced, and this helped to adjust the neurosurgical strategy.
This new full tractography approach simplifies the tractography pipeline and provides a reliable 3D-rendering of the spinal cord that could help to adjust the neurosurgical strategy.