title: Quantitative MR imaging evaluation of chondropathy in osteoarthritic knees.
abstract: OBJECTIVE
  To determine the validity and the reliability of T1-weighted three-dimensional gradient-echo magnetic resonance (MR) imaging for quantification of articular cartilage abnormalities of osteoarthritic knees.
  
  
  METHODS
  Forty-three patients (mean age, 63 years) with knee osteoarthritis (American College of Rheumatology criteria) of the medial tibiofemoral compartment underwent a prospective, cross-sectional study. Knees were examined with a T1-weighted three-dimensional gradient-echo sequence (1.4-mm contiguous sections), with use of a 0.2-T dedicated MR unit, before arthroscopic exploration. The tibiofemoral articular cartilage abnormalities were quantified blindly on both the MR and arthroscopic images with the French Society of Arthroscopy (SFA) score (0-100) and grading scheme (five grades).
  
  
  RESULTS
  There was a statistically significant correlation between the SFA-arthroscopic score and the SFA-MR score (r = .83) and between the SFA-arthroscopic grade and the SFA-MR grade (weighted kappa = 0.84). The deepest cartilage lesions graded with arthroscopy and MR imaging showed correlation in the medial femoral condyle (weighted kappa = 0.83) and in the medial tibial plateau (weighted kappa = 0.84). The intraobserver reliability of the SFA-MR score was higher (r = .94) than the interobserver reliability (r = .80).
  
  
  CONCLUSIONS
  Quantification of chondropathy with MR imaging is feasible and well correlated with anatomic cartilage breakdown.
authors.affiliation: Department of Radiology, Hôpital Cochin, Paris, France.
authors.forename: J L
authors.initials: JL
authors.lastname: Drapé
authors.forename: E
authors.initials: E
authors.lastname: Pessis
authors.forename: G R
authors.initials: GR
authors.lastname: Auleley
authors.forename: A
authors.initials: A
authors.lastname: Chevrot
authors.forename: M
authors.initials: M
authors.lastname: Dougados
authors.forename: X
authors.initials: X
authors.lastname: Ayral
mesh_terms: D000368:Aged; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000473:pathology*; D003430:Cross-Sectional Studies; D005069:Evaluation Studies as Topic; D005240:Feasibility Studies; D005260:Female; D005269:Femur / Q000473:pathology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology; D008875:Middle Aged; D015588:Observer Variation; D010003:Osteoarthritis / Q000145:classification / Q000473:pathology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D016037:Single-Blind Method; D013977:Tibia / Q000473:pathology