title: Normal variation of diffusion tensor parameters of the spinal cord in healthy subjects at 3.0-Tesla.
abstract: OBJECTIVE
  The purposes of the present study were to clarify the normal variation and to determine the normal reference values of diffusion tensor (DT) parameters (mean diffusivity [MD] and fractional anisotropy [FA]) of the spinal cord in single-shot fast spin-echo-based sequence at 3.0-Tesla (3T).
  
  
  METHODS
  Thirty healthy subjects (mean age = 44.2 years, range = 20-72 years) were enrolled for this study. Mean values of MD and FA in six spinal levels (C2/3, C3/4, C4/5, C5/6, C6/7, and C7/Th1) were measured. Mean values, variances, and distributions of the MD and FA in each spinal level were analyzed. Age-dependent change of MD and FA as well as correlation between MD and FA was also analyzed.
  
  
  RESULTS
  At all spinal levels, the values can be considered to be Gaussian distribution in MD but not in FA. A significant statistical negative correlation was observed between aging and the values of MD (r = 0.429, P = 0.018), but insignificant between the values of FA (P = 0.234). A slight significant statistical negative correlation was observed between the values of MD and FA (r = 0.156, P = 0.037). One way repeated measures analysis of variance indicated the significant difference between the spinal levels in both MD (P = 0.003) and FA (P < 0.0001).
  
  
  CONCLUSIONS
  The analyzed data in the present study would be helpful for comparison when investigating the spinal condition of spinal disorders.
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka City, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uda
authors.forename: T
authors.initials: T
authors.lastname: Takami
authors.forename: S
authors.initials: S
authors.lastname: Sakamoto
authors.forename: N
authors.initials: N
authors.lastname: Tsuyuguchi
authors.forename: T
authors.initials: T
authors.lastname: Yamagata
authors.forename: K
authors.initials: K
authors.lastname: Ohata
keywords: Diffusion tensor imaging; fractional anisotropy; mean diffusivity; normal subjects; spinal cord