title: Lesion growth and degeneration patterns measured using diffusion tensor 9.4-T magnetic resonance imaging in rat spinal cord injury.
abstract: OBJECTIVE
  Using diffusion tensor MR imaging, the authors conducted a study to explore lesion growth and degeneration patterns, from the acute through chronic stages of spinal cord injury (SCI), in an experimental animal model.
  
  
  METHODS
  In vivo and ex vivo diffusion tensor imaging was performed using a 9.4-T MR imaging system in rats allowed to recover from traumatic contusion SCI from 2 weeks through 25 weeks postinjury, mimicking progression of human SCI from the acute through chronic stages.
  
  
  RESULTS
  Results showed significant growth of the traumatic lesion up to 15 weeks postinjury, where both the size and mean diffusivity (MD) reached a maximum that was maintained through the remainder of recovery. Mean diffusivity was sensitive to overall spinal cord integrity, whereas fractional anisotropy showed specificity to sites of cavity formation. The use of an MD contour map for in vivo data and a 3D surface map for ex vivo data, showing MD as a function of rostral-caudal distance and recovery time, allowed documentation of rostral and caudal spreading of the lesion.
  
  
  CONCLUSIONS
  Results from this study demonstrate changes in both lesion morphology and diffusivity beyond previously reported time points and provide a unique perspective on the process of cavity formation and degeneration following traumatic SCI. Additionally, results suggest that MD more accurately defines regions of histological damage than do regions of T2 signal hyperintensity. This could have significant clinical implications in the detection and potential treatment of posttraumatic syringes in SCI.
authors.affiliation: Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin 53201, USA.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ellingson
authors.forename: Brian D
authors.initials: BD
authors.lastname: Schmit
authors.forename: Shekar N
authors.initials: SN
authors.lastname: Kurpad
mesh_terms: D000208:Acute Disease; D000818:Animals; D002908:Chronic Disease; D056324:Diffusion Tensor Imaging; D018450:Disease Progression; D005260:Female; D009410:Nerve Degeneration / Q000473:pathology* / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000473:pathology / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000503:physiopathology*