title: Glenohumeral position during CT arthrography with arthroscopic correlation: optimization of diagnostic yield.
abstract: OBJECTIVE
  To evaluate the diagnostic yield of two acquisitions of single-contrast CT arthrography (CTA) of the shoulder in internal, neutral, or external glenohumeral rotation with arthroscopic correlation.
  
  
  METHODS
  The CT study was obtained using two acquisitions (first the humerus positioned in maximum tolerated external rotation with the arm along the body and the second with the humerus in internal rotation with the palm placed flat on the table). Two independent readers blinded to the arthroscopic results evaluated the CTA images for labral tears, glenoid bone loss/fractures, and cartilage loss. For each CTA acquisition, sensitivity and specificity for detection of the aforementioned pathology were assessed. Inter-reader agreement was quantified by weighted ĸ statistics.
  
  
  RESULTS
  Sensitivity and specificity for detecting anteroinferior or posterior labral tears was highest with neutral rotation (sensitivity 91-100%, specificity 61-100%). For glenoid fracture, sensitivity (67%) was highest with external rotation and specificity (100%) was highest with internal rotation. For cartilage loss, sensitivity (64%) and specificity (89%) was highest with external rotation and neutral rotation, respectively. Neutral rotation showed high sensitivity and specificity for glenoid fractures and cartilage loss. Inter-reader agreement ranged from fair to very good.
  
  
  CONCLUSIONS
  Neutral glenohumeral position in shoulder CT arthrography was adequately sensitive and specific for the detection of intra-articular pathology, avoiding the use of more than one acquisition.
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6046, Boston, MA, 02114, USA. fsimeone@partners.org.
authors.forename: F Joseph
authors.initials: FJ
authors.lastname: Simeone
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6046, Boston, MA, 02114, USA.
authors.forename: Corey M
authors.initials: CM
authors.lastname: Gill
authors.affiliation: Musculoskeletal Imaging, Hospital Israelita Albert Einstein, Hospital do Coração (HCor) and Teleimagem, São Paulo, SP, Brazil.
authors.forename: Atul K
authors.initials: AK
authors.lastname: Taneja
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6046, Boston, MA, 02114, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Torriani
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6046, Boston, MA, 02114, USA.
authors.forename: Miriam A
authors.initials: MA
authors.lastname: Bredella
mesh_terms: D000293:Adolescent; D000328:Adult; D001175:Arthrography / Q000379:methods*; D001182:Arthroscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning / Q000379:methods*; D012680:Sensitivity and Specificity; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: CT arthrography; Glenohumeral rotation; Glenoid bone loss; Labral tear; Radiation exposure; Shoulder instability