title: Indirect magnetic resonance arthrography of the shoulder; a reliable diagnostic tool for investigation of suspected labral pathology.
abstract: OBJECTIVE
  Indirect magnetic resonance arthrography (I-MRA) confers significant logistical advantages over direct MRA and does not require articular injection. In this study, we determined the diagnostic performance of I-MRA in relation to conventional MRI and arthroscopy or surgery in detecting tears of the glenoid labrum, including Bankart lesions and superior labral antero-posterior (SLAP) tears in a standard clinical setting.
  
  
  METHODS
  Ninety-one symptomatic patients underwent conventional MRI and I-MRA of the affected shoulder, followed by either arthroscopy or open surgery. The scans were interpreted independently by two experienced radiology consultants with a special interest in musculoskeletal radiology. Using the surgical findings as the standard of reference, sensitivity, specificity, and diagnostic accuracy of conventional non-contrast MRI and I-MRA in the detection of labral tears were calculated.
  
  
  RESULTS
  The sensitivity of I-MRA was 95 and 97 %, respectively, for two radiologists as opposed to 79 and 83 % for conventional MRI. For both radiologists, the specificity of I-MRA, as well as MRI, was 91 % for detection of labral tears of all types. Accuracy of diagnosis was 93 and 95 %, respectively, for two radiologists with indirect MRA, compared to 84 and 86 % with non-contrast MRI.
  
  
  CONCLUSIONS
  This retrospective study shows that I-MRA is a highly accurate and sensitive method for the detection of labral tears. The data obtained supports the use of I-MRA as standard practice in patients with shoulder instability due to suspected labral pathology where further investigative imaging is indicated.
authors.affiliation: North Cumbria University Hospitals NHS Trust, Cumberland Infirmary, Carlisle CA2 7HY, UK. farshid.fallahi@ncuh.nhs.uk
authors.forename: Farshid
authors.initials: F
authors.lastname: Fallahi
authors.forename: Nick
authors.initials: N
authors.lastname: Green
authors.forename: Sarat
authors.initials: S
authors.lastname: Gadde
authors.forename: Lisa
authors.initials: L
authors.lastname: Jeavons
authors.forename: Patrick
authors.initials: P
authors.lastname: Armstrong
authors.forename: Leon
authors.initials: L
authors.lastname: Jonker
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D051445:Fibrocartilage / Q000293:injuries* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012421:Rupture / Q000473:pathology; D012680:Sensitivity and Specificity; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000473:pathology*