title: Quantitative measurement of femoral condyle cartilage in the knee by MRI: validation study by multireaders.
abstract: OBJECTIVE
  To determine reproducibility of the femoral condyle cartilage volume (CV) in cross-sectional and longitudinal studies using various 3D imaging techniques at 1.5 T and 3 T.
  
  
  METHODS
  In 21 subjects with osteoarthritis, magnetic resonance imaging (MRI) including four different sequences (sagittal 3D fat suppressed spoiled gradient-echo [SPGR] at 1.5 T, fat suppressed fast low angle shot [FLASH] at 3 T, water-excitation dual echo steady state [DESS] at 3 T, and water-excitation multiecho data image combination [MEDIC] at 3 T) were acquired at baseline and ∼1 year later. The CV measured using semiautomated segmentation software by three readers was analyzed.
  
  
  RESULTS
  The mean of the interclass correlation coefficient between each reader from SPGR, FLASH, DESS, and MEDIC was 0.899, 0.948, 0.943, and 0.954, respectively. The mean CV (×10(4) mm(3) ) measured by each reader from SPGR/FLASH/DESS/MEDIC sequences was the following in this order: 1.34/1.52/1.50/1.35, 1.21/1.43/1.40/1.27, 1.22/1.37/1.36/1.22, and 1.17/1.36/1.35/1.21 by readers 1, 2, 3 (first analysis), and 3 (second analysis), respectively. There was no statistically significant difference in CV between any readers in any sequences. The CV measured on FLASH and DESS tended to be greater than that on SPGR or MEDIC.
  
  
  CONCLUSIONS
  Inter- and intraobserver reproducibility of cartilage segmentation using semiautomated software was validated. Although there was no statistical significance, there was a tendency of under- or overestimating CV by each sequence.
authors.affiliation: Department of Radiological Sciences, University of California, Irvine, California, USA; Department of Radiology, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Fujinaga
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshioka
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sakai
authors.forename: Yoko
authors.initials: Y
authors.lastname: Sakai
authors.forename: Felipe
authors.initials: F
authors.lastname: Souza
authors.forename: Philipp
authors.initials: P
authors.lastname: Lang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D005269:Femur / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D020370:Osteoarthritis, Knee / Q000473:pathology*; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: knee cartilage; magnetic resonance imaging; reproducibility; segmentation