title: Correlation between T2 relaxation time and intervertebral disk degeneration.
abstract: OBJECTIVE
  Magnetic resonance T2 mapping allows for the quantification of water and proteoglycan content within tissues and can be used to detect early cartilage abnormalities as well as to track the response to therapy. The goal of the present study was to use T2 mapping to quantify intervertebral disk water content according to the Pfirrmann classification.
  
  
  METHODS
  This study involved 60 subjects who underwent lumbar magnetic resonance imaging (a total of 300 lumbar disks). The degree of disk degeneration was assessed in the midsagittal section on T2-weighted images according to the Pfirrmann classification (grades I to V). Receiver operating characteristic (ROC) analysis was performed among grades to determine the cut-off values.
  
  
  RESULTS
  In the nucleus pulposus, T2 values tended to decrease with increasing grade, and there was a significant difference in T2 values between each grade from grades I to IV. However, there was no significant difference in T2 values in the anterior or posterior annulus fibrosus. T2 values according to disk degeneration level classification were as follows: grade I (>116.8 ms), grade II (92.7-116.7 ms), grade III (72.1-92.6 ms), grade IV (<72.0 ms).
  
  
  CONCLUSIONS
  T2 values decreased with increasing Pfirrmann classification grade in the nucleus pulposus, likely reflecting a decrease in proteoglycan and water content. Thus, T2 value-based measurements of intervertebral disk water content may be useful for future clinical research on degenerative disk diseases.
authors.affiliation: Department of Orthopedic Surgery, School of Medicine, Sapporo Medical University, South-1, West-16, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan. takashima@sapmed.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takashima
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Takebayashi
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Terashima
authors.forename: Hajime
authors.initials: H
authors.lastname: Tsuda
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ida
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007403:Intervertebral Disc / Q000473:pathology*; D055959:Intervertebral Disc Degeneration / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D013223:Statistics as Topic