Superior labral anterior-to-posterior lesions: comparison of external rotation and active supination CT arthrography with neutral CT arthrography

To compare the diagnostic performance of computed tomographic (CT) arthrography performed with external rotation and active supination (ERAS) with that of CT angiography performed in the neutral position for superior labral anterior-to-posterior (SLAP) lesions.

Institutional review board approval and informed consent were obtained. CT arthrography in neutral and ERAS positions was performed in 49 shoulders of 47 patients, with subsequent arthroscopic confirmation of the status of the superior labrum. Two musculoskeletal radiologists (1 and 8 years of experience) reviewed images and expressed the likelihood of SLAP lesions by using a continuous scale; they also measured gap widths and depths of labral detachment. Overall performances for the detection of SLAP lesions were determined with receiver-operating characteristic (ROC) analysis. Gap widths and depths measured with the two types of CT arthrography were also compared.

For reader 1, area under the ROC curve increased insignificantly from 0.932 in the neutral position to 0.974 in the ERAS position (P = .210), whereas for reader 2, it increased significantly from 0.914 to 0.984 (P = .032). Mean gap width of SLAP lesion was significantly greater according to ERAS CT arthrography (3.98 mm ± 2.48 [standard deviation] vs 1.61 mm ± 1.11), whereas mean gap depth was not significantly different. Gap width and depth cutoff values for the detection of a SLAP lesion with ERAS CT arthrography were 1.7 mm and 1.6 mm, respectively.

ERAS CT arthrography might improve the detection of SLAP lesions compared with neutral-position CT arthrography.