title: Diagnosis of acetabular labral tears: comparison of three-dimensional intermediate-weighted fast spin-echo MR arthrography with two-dimensional MR arthrography at 3.0 T.
abstract: BACKGROUND
  Magnetic resonance (MR) arthrography is the ideal imaging modality for the acetabular labrum. Three-dimensional (3D) fast spin-echo (FSE) sequences have similar diagnostic performance as two-dimensional (2D) conventional MR imaging for ligaments, menisci, or bone marrow edema in the knee.
  
  
  OBJECTIVE
  To compare the diagnostic accuracy and inter-observer reliability of 3D intermediate-weighted FSE sequence and 2D FSE sequences for the diagnosis of acetabular labral tears.
  
  
  METHODS
  Institutional review board approval was obtained and informed consent was waived for 45 patients (47 hips) who underwent 3D and 2D MR arthrography and subsequent arthroscopic surgery. The 3D sequences were performed using volumetric intermediate-weighted fast spin-echo imaging with fat suppression (voxel size, 0.6 × 0.6 × 1.2 mm; imaging time, 6 min 38 s). Labral tear was retrospectively and independently evaluated by two radiologists in four areas of the labrum (anterosuperior, posterosuperior, anteroinferior, and posteroinferior) on 3D and 2D FSE sequences. Statistical differences between the sensitivity and specificity of the methods were analyzed with the McNemar test, using arthroscopic findings as the reference standard. Inter-observer agreement was calculated using kappa statistics.
  
  
  RESULTS
  Arthroscopic findings confirmed labral tears at 40 anterosuperior, 23 posterosuperior, 0 anteroinferior, and 2 posteroinferior quadrants. Sensitivity and specificity were 74% and 89% for 2D FSE sequences, and 78% and 92% for 3D FSE sequences, respectively. Sensitivities and specificities for the methods were not different statistically (P > 0.05). Inter-observer agreement for labral tear was substantial for 2D FSE sequences (κ = 0.774) and almost perfect for 3D FSE sequences (κ = 0.842).
  
  
  CONCLUSIONS
  3D intermediate-weighted FSE MR arthrography is excellent for diagnosing acetabular labral tears. Sensitivity, specificity, and inter-observer reliability were similar to conventional 2D MR arthrography. For evaluation of the labrum, 3D FSE MR arthrography is more time-efficient than 2D FSE MR arthrography.
authors.affiliation: Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Park
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Park
authors.forename: Wook
authors.initials: W
authors.lastname: Jin
authors.forename: Kee Hyung
authors.initials: KH
authors.lastname: Rhyu
authors.forename: Kyung Nam
authors.initials: KN
authors.lastname: Ryu
mesh_terms: D000077:Acetabulum / Q000293:injuries* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D001182:Arthroscopy; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D025981:Hip Injuries / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA