title: Longitudinal assessment of spinal cord injuries in nonhuman primates with quantitative magnetization transfer.
abstract: OBJECTIVE
  This study aimed to evaluate the reproducibility and specificity of quantitative magnetization transfer (qMT) imaging for monitoring spinal cord injuries (SCIs).
  
  
  METHODS
  MRI scans were performed in anesthetized monkeys at 9.4T, before and serially after a unilateral lesion of the cervical spinal cord. A two-pool fitting model was used to derive qMT parameters.
  
  
  RESULTS
  qMT measures were reproducible across normal subjects, with an average pool size ratio (PSR) of 0.086 ± 0.003 (mean ± SD) for gray matter, and 0.120 ± 0.005 for white matter, respectively. Compared with normal gray matter, the PSR of abnormal tissues rostral and caudal to the injury site decreased by 19.5% (P < 0.05), while the PSR of the cyst-like volume decreased drastically weeks after SCI. Strong correlations in cyst-like regions were observed between PSR and other MRI measures including longitudinal relaxation rate (R1 ), apparent diffusion coefficient and fractional anisotropy (FA). Decreased PSR and FA values correlated well with demyelination in abnormal tissues.
  
  
  CONCLUSIONS
  The qMT parameters provide robust and specific information about the molecular and cellular changes produced by SCI. PSR detected demyelination and loss of macromolecules in abnormal tissue regions rostral and caudal to the cyst/lesion sites.
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.|Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.|Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.|Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Arabinda
authors.initials: A
authors.lastname: Mishra
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.|Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gochberg
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.|Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.|Psychology, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Min Chen
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.|Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.|Psychology, Vanderbilt University, Nashville, Tennessee, USA.|Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Gore
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D003711:Demyelinating Diseases / Q000000981:diagnostic imaging*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012453:Saimiri; D013119:Spinal Cord Injuries / Q000000981:diagnostic imaging* / Q000473:pathology
keywords: 9.4T; MRI; cyst; demyelination; quantitative magnetization transfer (qMT); spinal cord injury