title: Quantitative T2 mapping of the patella at 3.0T is sensitive to early cartilage degeneration, but also to loading of the knee.
abstract: OBJECTIVE
  The aim of the study was to explore the sensitivity and robustness of T2 mapping in the detection and quantification of early degenerative cartilage changes at the patella.
  
  
  METHODS
  Forty-two patients (22 women, 20 men) with a mean age of 30.3 years and a symptomatic cartilage defect of ICRS grade ≤2 were examined using a 3T MRI with an 8-channel knee coil. The cartilage lesion was graded based on high-resolution PD TSE and 3D isotropic TrueFISP images. T2 maps were calculated from a standard MESE-sequence, performed at the beginning and at the end of the scan (40min in-between). Depending on the defect size, a region-of-interest (ROI) analysis was performed on 1-3 consecutive slices. Mean T2 values for the deep, superficial, and global layer as well as the zonal variation were compared among defect grades (ANOVA, post hoc Duncan-test) and over time (Student's t-test).
  
  
  RESULTS
  T2-measurements directly correlated with the extent of cartilage defect (ICRS grade) at all layers and at both time-points. However, correlations were closer for the second measurement at the end of the scan. In this unloaded state, differences in T2-values became more pronounced and were significant even between cartilage of normal appearance adjacent to the defect and healthy cartilage of control patients (both ICRS grade 0). In contrast, there were no such differences among grades in the zonal variation at any time.
  
  
  CONCLUSIONS
  T2 mapping might be a sensitive method for the detection of early cartilage degeneration at the patella in the unloaded joint.
authors.affiliation: Department of Radiology, Medical University of Vienna, MR Center - Highfield MR, Vienna, Austria. sebastian.apprich@meduniwien.ac.at
authors.forename: S
authors.initials: S
authors.lastname: Apprich
authors.forename: T C
authors.initials: TC
authors.lastname: Mamisch
authors.forename: G H
authors.initials: GH
authors.lastname: Welsch
authors.forename: D
authors.initials: D
authors.lastname: Stelzeneder
authors.forename: C
authors.initials: C
authors.lastname: Albers
authors.forename: U
authors.initials: U
authors.lastname: Totzke
authors.forename: S
authors.initials: S
authors.lastname: Trattnig
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000503:physiopathology*; D010329:Patella / Q000473:pathology* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016474:Weight-Bearing; D055815:Young Adult