title: Magnetic resonance imaging-based assessment of cartilage loss in severe osteoarthritis: accuracy, precision, and diagnostic value.
abstract: OBJECTIVE
  To examine the in vivo accuracy and precision of magnetic resonance imaging (MRI)-based assessment of cartilage loss in patients with severe osteoarthritis (OA) of the knee.
  
  
  METHODS
  High-resolution MRI images of the tibial cartilage were obtained in 8 patients prior to total knee arthroplasty, using a water-excitation gradient-echo MRI sequence (acquisition time 6 minutes 19 seconds; spatial resolution 1.2 x 0.31 x 0.31 mm3). The MRI measurements were repeated after joint repositioning. The precision of the cartilage volume and thickness computations was determined after 3-dimensional reconstruction. During surgery, the tibial plateaus were resected, and the MRI data were compared with water displacement of surgically retrieved cartilage.
  
  
  RESULTS
  The standard deviation (coefficient of variation) of repeated tibial cartilage volume measurements was 56 mm3 (5.5%) medially and 59 mm3 (3.8%) laterally. The deviation from surgically removed tissue was -13%, on average, with a high linear correlation between both methods (r = 0.98). In patients with varus OA, the tissue loss was estimated to be 1,290 mm3 in the medial tibia and 1,150 mm3 in the lateral tibia, compared with the data in healthy volunteers.
  
  
  CONCLUSIONS
  Noninvasive quantitative MRI-based analysis of cartilage morphometry in severe OA is accurate, precise, and displays high potential diagnostic value.
authors.affiliation: Klinik für Orthopädie und Sportorthopädie, Technische Universität München, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Burgkart
authors.forename: C
authors.initials: C
authors.lastname: Glaser
authors.forename: A
authors.initials: A
authors.lastname: Hyhlik-Dürr
authors.forename: K H
authors.initials: KH
authors.lastname: Englmeier
authors.forename: M
authors.initials: M
authors.lastname: Reiser
authors.forename: F
authors.initials: F
authors.lastname: Eckstein
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002356:Cartilage / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000592:standards*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000601:surgery; D015203:Reproducibility of Results; D013977:Tibia