Indirect MR Arthrographic Findings of Adhesive Capsulitis

OBJECTIVE. The objective of our study was to compare the indirect MR arthrographic findings of patients with adhesive capsulitis and patients without adhesive capsulitis. MATERIALS AND METHODS. Indirect MR arthrograms of 35 patients (21 women, 14 men; mean age, 50.1 years) diagnosed with adhesive capsulitis clinically were compared with indirect MR arthrograms of 45 patients (23 women, 22 men; mean age, 48.9 years) without adhesive capsulitis. Joint capsule thickness in the axillary recess and the thicknesses of the enhancing portion of the axillary recess and the rotator interval were, respectively, evaluated on coronal T2-weighted images and coronal and sagittal fat-suppressed enhanced T1-weighted images by two radiologists independently. Reliability was studied using the intraclass correlation coefficient (ICC). Receiver operating characteristic (ROC) curves were compared. RESULTS. Patients with adhesive capsulitis had significantly thickened joint capsules in the axillary recess and a thickened enhancing portion in the axillary recess and in the rotator interval. The difference in the thicknesses of the enhancing portion in the axillary recess and in the rotator interval were significantly greater than the difference in joint capsule thicknesses in the axillary recess between the adhesive capsulitis group and the control group (p < 0.001). Interobserver reliability was good for all three indexes (ICC >= 0.80). The area under the ROC curve for the thickness of the joint capsule in the axillary recess and the thicknesses of the enhancing portion of the axillary recess and the rotator interval were 0.797, 0.861, and 0.847, respectively. CONCLUSION. An abundance of enhancing tissue in the rotator interval and thickening and enhancement of the axillary recess are signs suggestive of adhesive capsulitis on indirect MR arthrography.