title: Longitudinal study on diffusion tensor imaging and diffusion tensor tractography following spinal cord contusion injury in rats.
abstract: BACKGROUND
  Diffusion tensor imaging (DTI) as a potential technology has been used in spinal cord injury (SCI) studies, but the longitudinal evaluation of DTI parameters after SCI, and the correlation between DTI parameters and locomotor outcomes need to be defined.
  
  
  METHODS
  Adult Wistar rats (n = 6) underwent traumatic thoracic cord contusion by an NYU impactor. DTI and Basso-Beattie-Bresnahan datasets were collected pre-SCI and 1, 3, 7, 14, and 84 days post-SCI. Diffusion tensor tractography (DTT) of the spinal cord was also generated. Fractional anisotropy (FA) and connection rate of fibers at the injury epicenter and at 5 mm rostral/caudal to the epicenter were calculated. The variations of these parameters after SCI were observed by one-way analysis of variance and the correlations between these parameters and motor function were explored by Pearson's correlation.
  
  
  RESULTS
  FA at the epicenter decreased most remarkably on day 1 post-SCI (from 0.780 ± 0.012 to 0.330 ± 0.015), and continued to decrease slightly by day 3 post-SCI (0.313 ± 0.015), while other parameters decreased significantly over the first 3 days after SCI. DTT showed residual fibers concentrated on ventral and ventrolateral sides of the cord. Moreover, FA at the epicenter exhibited the strongest correlation (r = 0.887, p = 0.000) with the locomotion performance.
  
  
  CONCLUSIONS
  FA was sensitive to degeneration in white matter and DTT could directly reflect the distribution of the residual white matter. Moreover, days 1 to 3 post-SCI may be the optimal time window for SCI examination and therapy.
authors.affiliation: Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, 37 Xueyuan Road, Beijing, 100191, China.
authors.forename: Can
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, 37 Xueyuan Road, Beijing, 100191, China.
authors.forename: Jia-Sheng
authors.initials: JS
authors.lastname: Rao
authors.affiliation: Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China.|Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100043, China.
authors.forename: Xiao-Jiao
authors.initials: XJ
authors.lastname: Pei
authors.affiliation: Medical Experiment and Test Center, Capital Medical University, Beijing, 100069, China.
authors.forename: Jian-Feng
authors.initials: JF
authors.lastname: Lei
authors.affiliation: Medical Experiment and Test Center, Capital Medical University, Beijing, 100069, China.
authors.forename: Zhan-Jing
authors.initials: ZJ
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, 37 Xueyuan Road, Beijing, 100191, China. wack_lily@163.com.|Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China. wack_lily@163.com.
authors.forename: Zhao-Yang
authors.initials: ZY
authors.lastname: Yang
authors.affiliation: Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, 37 Xueyuan Road, Beijing, 100191, China. bhbmeuniversity@gmail.com.|Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China. bhbmeuniversity@gmail.com.
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Li
mesh_terms: D000375:Aging / Q000473:pathology*; D000818:Animals; D056324:Diffusion Tensor Imaging / Q000379:methods*; D018450:Disease Progression; D005260:Female; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008137:Longitudinal Studies; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013119:Spinal Cord Injuries / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D013382:Subtraction Technique; D066127:White Matter / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology
keywords: Connection rate of fibers; Diffusion tensor imaging; Diffusion tensor tractography; Fractional anisotropy; Spinal cord injury