Abstract： Objective To analyze the imaging characteristics and the diagnostic value of conventional MRI and indirect MR arthrography in shoulder joint injury.Methods MR imaging in90 patients with shoulder joint disease were retrospectively analyzed by two musculoskeletal radiologist based on the results of arthroseopic examination,including 57 cases of rotator cuff disease and 33 cases of recurrent shoulder instability.The result of the indirect MR arthrography and conventional MR was statistically compared by Fisher exact probability test.Results (1)In the group of rotator cuff disease,37 patients underwent indirect MRA,demonstrating 10 cases of partial-thickness rotator cuff tear and 1 case of missed diagnosis;demonstrating 17 cases of full-thickness rotator cuff tear and 2 cases of misdiagnosis.For partialthickness rotator cuff tear,the sensitivity,specificity and accuracy of indirect MR arthrography were 90.9%(10/11),92.3%(24/26),and 91.9%(34/37),respectively;for full-thickness rotator cuff tear,the sensitivity,specificity and accuracy of indirect MR arthrography were 89.5%(17/19),94.4%(17/18),and 91.9%(34/37),respectively.Indirect MR arthrography in the diagnosis of partial and full thickness rotator cuff was significantly better than conventional MR(P＜0.05).(2)In the group of recurrent shoulder instability,labium tear was found in 26 cases,Hill-sachs lesion in 27,reverse Hill-sachs in 2,bony Bankart lesion in 7,and capsular tear in 18 cases,respectively.Twenty patients underwent indirect MRA,demonstrating 14 cases of labrum tear,1 case of missed diagnosis,and 5 cases of normal labrum.For labrum tear,the sensitivity,specificity and accuracy of indirect MR arthrography were 93.3%(14/15),100.0%(5/5),and 95.0%(19/20),respectively.Indirect MR arthrography in the diagnosis of labrum tear was significantly better than conventional MR(P＜0.05).Conclusion MRI,especially indirect MR arthrography,is the most helpful method for the diagnoses of shoulder joint injury.