title: Diagnostic accuracy of MRI in the measurement of glenoid bone loss.
abstract: OBJECTIVE
  The purpose of this study is to assess the accuracy of MRI quantification of glenoid bone loss and to compare the diagnostic accuracy of MRI to CT in the measurement of glenoid bone loss.
  
  
  METHODS
  MRI, CT, and 3D CT examinations of 18 cadaveric glenoids were obtained after the creation of defects along the anterior and anteroinferior glenoid. The defects were measured by three readers separately and blindly using the circle method. These measurements were compared with measurements made on digital photographic images of the cadaveric glenoids. Paired sample Student t tests were used to compare the imaging modalities. Concordance correlation coefficients were also calculated to measure interobserver agreement.
  
  
  RESULTS
  Our data show that MRI could be used to accurately measure glenoid bone loss with a small margin of error (mean, 3.44%; range, 2.06-5.94%) in estimated percentage loss. MRI accuracy was similar to that of both CT and 3D CT for glenoid loss measurements in our study for the readers familiar with the circle method, with 1.3% as the maximum expected difference in accuracy of the percentage bone loss between the different modalities (95% confidence).
  
  
  CONCLUSIONS
  Glenoid bone loss can be accurately measured on MRI using the circle method. The MRI quantification of glenoid bone loss compares favorably to measurements obtained using 3D CT and CT. The accuracy of the measurements correlates with the level of training, and a learning curve is expected before mastering this technique.
authors.affiliation: Department of Radiology, New York University Hospital for Joint Diseases, 301 East 17th St, New York, NY 10003, USA. Soterios20@gmail.com
authors.forename: Soterios
authors.initials: S
authors.lastname: Gyftopoulos
authors.forename: Saqib
authors.initials: S
authors.lastname: Hasan
authors.forename: Jenny
authors.initials: J
authors.lastname: Bencardino
authors.forename: Jason
authors.initials: J
authors.lastname: Mayo
authors.forename: Samir
authors.initials: S
authors.lastname: Nayyar
authors.forename: James
authors.initials: J
authors.lastname: Babb
authors.forename: Laith
authors.initials: L
authors.lastname: Jazrawi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001862:Bone Resorption / Q000175:diagnosis* / Q000000981:diagnostic imaging; D061827:Dimensional Measurement Accuracy; D005260:Female; D061165:Glenoid Cavity / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D014057:Tomography, X-Ray Computed; D055815:Young Adult