title: Diffusion tensor imaging and T2 mapping in early denervated skeletal muscle in rats.
abstract: BACKGROUND
  To evaluate the temporal changes of diffusion tensor imaging (DTI) indices, T2 values, and visual signal intensity on various fat suppression techniques in the early state of denervated skeletal muscle in a rat model.
  
  
  METHODS
  Institutional Animal Care and Use Committee approval was obtained. Sciatic nerves of eight rats were transected for irreversible neurotmesis model. We examined normal lower leg and denervated muscles at 3 days, 1 week, and 2 weeks on a 3 Tesla MR. fractional anisotropy (FA), mean apparent diffusion coefficient (mADC), and T2 values were measured by using DTI and T2 mapping scan. We subjectively classified the signal intensity change on various fat suppression images into the following three grades: negative, suspicious, and definite change. Wilcoxon-sign rank test and Kruskal-Wallis test were used for the comparison of FA, mADC, T2 values. McNemar's test was used for comparing signal intensity change among fat suppression techniques.
  
  
  RESULTS
  FA values of denervated muscles at 3 days (0.35 ± 0.06), 1 week (0.29 ± 0.04), and 2 weeks (0.34 ± 0.05) were significantly (P < 0.05) lower than that in the control group (0.54 ± 0.17). mADC of denervated muscles decreased without statistically significant (P > 0.05) change. T2 values were significantly increased at 1 week (38.11 ± 6.42 ms, P = 0.017) and markedly increased at 2 weeks (46.53 ± 5.17 ms, P = 0.012). The grade of visual signal intensity change on chemical shift selective fat saturation, STIR and IDEAL images were identical in all cases (P = 1.000).
  
  
  CONCLUSIONS
  FA and T2 values can demonstrate the early temporal changes in denervated rat skeletal muscle.
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Busan, Korea.
authors.forename: Dong-Ho
authors.initials: DH
authors.lastname: Ha
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Busan, Korea.
authors.forename: Sunseob
authors.initials: S
authors.lastname: Choi
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Busan, Korea.
authors.forename: Eun-Ju
authors.initials: EJ
authors.lastname: Kang
authors.affiliation: Department of Microbiology, Medical Science Research Institute, College of Medicine, Dong-A University, Busan, Korea.
authors.forename: Hwan Tae
authors.initials: HT
authors.lastname: Park
mesh_terms: D000818:Animals; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D006614:Hindlimb / Q000294:innervation; D007091:Image Processing, Computer-Assisted; D008297:Male; D009121:Muscle Denervation; D018482:Muscle, Skeletal / Q000294:innervation* / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000473:pathology*
keywords: T2 value; diffusion tensor imaging; magnetic resonance imaging; muscle denervation