Using abduction and external rotation of the shoulder to increase the sensitivity of MR arthrography in revealing tears of the anterior glenoid labrum.

OBJECTIVE: The purpose of this study was to compare oblique axial MR arthrograms obtained with the patient's shoulder in abduction and external rotation (ABER) position with conventional axial MR arthrograms obtained with the patient's arm in neutral position and the shoulder not rotated in revealing tears of the anterior glenoid labrum (AGL). SUBJECTS AND METHODS: MR arthrography of the shoulder that included an additional oblique axial imaging sequence with the patient in the ABER position was performed in 256 patients. Assessment of AGL integrity with patients in both conventional axial and ABER positions was made before surgery. These assessments were compared with the surgical findings.
RESULTS: Of the 92 patients who underwent surgery, AGL tears were found in 27. Conventional axial MR arthrograms revealed 13 tears (sensitivity, 48%; specificity, 91%). A separate review of MR arthrograms obtained with patients in the ABER position revealed 24 tears (sensitivity, 89%; specificity, 95%). Reviewed together, axial MR arthrograms and MR arthrograms obtained with patients in the ABER position revealed 26 tears (sensitivity, 96%; specificity, 97%).
CONCLUSION: Oblique axial MR arthrograms obtained with the patient's shoulder in the ABER position were significantly more sensitive in revealing AGL tears (p = .005) than were conventional axial MR arthrograms obtained with the patient's aim in a neutral position and the shoulder not rotated.