title: Full tensor diffusion imaging is not required to assess the white-matter integrity in mouse contusion spinal cord injury.
abstract: In vivo diffusion tensor imaging (DTI) derived indices have been demonstrated to quantify accurately white-matter injury after contusion spinal cord injury (SCI) in rodents. In general, a full diffusion tensor analysis requires the acquisition of diffusion-weighted images (DWI) along at least six independent directions of diffusion-sensitizing gradients. Thus, DTI measurements of the rodent central nervous system are time consuming. In this study, diffusion indices derived using the two-direction DWI (parallel and perpendicular to axonal tracts) were compared with those obtained using six-direction DTI in a mouse model of SCI. It was hypothesized that the mouse spinal cord ventral-lateral white-matter (VLWM) tracts, T8-T10 in this study, aligned with the main magnet axis (z) allowing the apparent diffusion coefficient parallel and perpendicular to the axis of the spine to be derived with diffusion-weighting gradients in the z and y axes of the magnet coordinate respectively. Compared with six-direction full tensor DTI, two-direction DWI provided comparable diffusion indices in mouse spinal cords. The measured extent of spared white matter after injury, estimated by anisotropy indices, using both six-direction DTI and two-direction DWI were in close agreement and correlated well with histological staining and behavioral assessment. The results suggest that the two-direction DWI derived indices may be used, with significantly reduced imaging time, to estimate accurately spared white matter in mouse SCI.
authors.affiliation: Department of Mechanical, Aerospace and Structural Engineering, Washington University in St. Louis, St. Louis, Missouri 63110, USA.
authors.forename: Tsang-Wei
authors.initials: TW
authors.lastname: Tu
authors.forename: Joong H
authors.initials: JH
authors.lastname: Kim
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Sheng-Kwei
authors.initials: SK
authors.lastname: Song
mesh_terms: D000818:Animals; D004396:Coloring Agents; D004058:Diffusion; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004185:Disability Evaluation; D004195:Disease Models, Animal; D005260:Female; D007091:Image Processing, Computer-Assisted; D007211:Indoles; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000502:physiology; D009186:Myelin Sheath / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D010243:Paralysis / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013116:Spinal Cord / Q000473:pathology* / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000175:diagnosis* / Q000473:pathology* / Q000503:physiopathology
chemical_list: D004396:Coloring Agents; D007211:Indoles; C018588:Luxol Fast Blue MBS