title: Articular cartilage volume in the knee: semiautomated determination from three-dimensional reformations of MR images.
abstract: OBJECTIVE
  To determine the accuracy of semiautomated quantification of articular cartilage volume from three-dimensional (3D) reformations of magnetic resonance (MR) images.
  
  
  METHODS
  Sagittal, fat-suppressed, 3D, spoiled gradient-recalled-echo MR imaging of two bovine and two human cadaver knees was performed. Articular cartilage volume was calculated from 3D reformations of the MR images by using a semiautomated program written at the authors' institution. Calculated volumes were compared with directly measured volumes of the surgically removed articular cartilage.
  
  
  RESULTS
  The percentage of error of the MR imaging-determined volumes was 6.53% +/- 4.75 (mean +/- standard deviation). A strong correlation between the two sets of observations was shown (r=.997). Linear regression showed the calculated volumes to be highly accurate (slope=1.002, P>.25). Repeated reformations yielded volumes that were reproducible (mean absolute error, 0.013 mL +/- 0.019) and not significantly different from the measured volume (P>.10).
  
  
  CONCLUSIONS
  Semiautomated quantification of knee articular cartilage from MR images yields highly accurate cartilage volumes.
authors.affiliation: Department of Radiology, Albany Medical College, New York 12208, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Piplani
authors.forename: D G
authors.initials: DG
authors.lastname: Disler
authors.forename: T R
authors.initials: TR
authors.lastname: McCauley
authors.forename: T J
authors.initials: TJ
authors.lastname: Holmes
authors.forename: J P
authors.initials: JP
authors.lastname: Cousins
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D002417:Cattle; D006801:Humans; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging