MRIによる外傷性肩関節不安定症の診断

抄録

In order to asses the accuracy of MRI findings in relation to glenoid labral lesions and rotator interval tears, we compared MRI findings and the observations of doctors during actual surgery.
30 shoulders were evaluated for lesions of the glenoid labrum. The diagnosis were: r ecurrent anterior dislocation in 18 shoulders, sports injuries in 7 shoulders and others in 5 shoulders. All were later treated surgically. In 22 of the 30 shoulders, MRinages were evaluated for the diagnosis of rotator interval tears. MRI was performed with superconduction units.
The criter on for a normal glenoid labrum on MRI was a well-defined, wedge shaped structure of low signal intensity adjacent to the glenoid rim. When an increased intensity was seen within the labrum or its margin was absent in the labral structure, we diagnosed it as an abnormal glenoid labrum. At operation, Bankart's lesions were seen in 19 of the 30 shoulders, glenoid labral tears in 4 shoulders and normal labral in 7 shoulders. There were 2 false-negative diagnoses and one falsepositive one on MRI. The sensitivity and specificty of MRI in the diagnoses of glenoid labral lesions were 91.3 and 85.7 per cent.
Rotator interval tears could also be diagnosed on MRI, showing as a large opening of high intensity between the supraspinatus and subscapularis tendons.
MRI is very useful in the diagnosis of traumatic an t erior or inferior instability of shoulders.