title: Comparison of T1ρ and T2* Relaxation Mapping in Patients with Different Grades of Disc Degeneration at 3T MR.
abstract: BACKGROUND
  T1ρ and T2* relaxation times are capable of providing information about early biochemical changes in intervertebral disk degeneration (IVDD). The purpose of this study was to assess and compare T1ρ and T2* mapping in IVDD with reference to Pfirrmann grade.
  
  
  METHODS
  Lumbar sagittal T2-weighted, T1ρ and T2* relaxation MRI were performed at 3.0T in 42 subjects covering discs L1-L2 to L5-S1. All the discs were morphologically assessed according to the Pfirrmann grade. Regions of interest (ROIs) were drawn over the T1ρ and T2*mappings, including nucleus pulposus (NP) and annulus fibrosus (AF). Wilcoxon signed rank test, Kruskal-Wallis test, and Spearman rank correlation were performed.
  
  
  RESULTS
  The difference in T1ρ and T2* values between NP and AF were highly significant (P<0.001). The trends of decreasing T1ρ and T2* values of both NP and AF with increasing Pfirrmann grades was significant (P<0.01), particularly between Pfirrmann grade II and III (P<0.001), whereas T2* mapping was additionally able to detect changes in the AF between Pfirrmann grade I and II (P<0.05). Pfirrmann grades were inversely significantly correlated with both T1ρ and T2* values in the NP (r=-0.69, P<0.001; r=-0.56, P<0.001) and AF (r=-0.45, P<0.001; r=-0.26, P<0.001).
  
  
  CONCLUSIONS
  The process of IVDD can be detected by T1ρ and T2* mapping, particularly at early stage, and both methodologies displayed roughly comparable performance.
authors.affiliation: Department of Radiology, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China (mainland).
authors.forename: Xinjuan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Shanghai Institute of Medical Imaging, Zhongshan Hospital, Fudan University, Shanghai, China (mainland).
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Radiology, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China (mainland).
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.affiliation: Department of Radiology, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China (mainland).
authors.forename: Zhenguo
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Department of Radiology, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China (mainland).
authors.forename: Xiangtao
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Radiology, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China (mainland).
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
authors.affiliation: Philips Healthcare, Shanghai, China (mainland).
authors.forename: Weibo
authors.initials: W
authors.lastname: Chen
authors.affiliation: Philips Healthcare, Hong Kong, China (mainland).
authors.forename: Queenie
authors.initials: Q
authors.lastname: Chan
authors.affiliation: Department of Radiology, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China (mainland).
authors.forename: Guangbin
authors.initials: G
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055815:Young Adult