抄録
(Purpose) MRI is very useful for the diagnosis of the rotator cuff tear. However, in cases of incomplete tears it is sometimes controvertible. In this study, we studied the accuracy of MRI's. in the diagnosis of full thickness and incomplete tears. We also compared the MRI findings with the operative findings in the assessment of the size of the rotator cuff tear.
(Materials and methods)75 patients who underwent MRI investigation before operation were chosen for this study. There were 69 males and 6 females, ranging from 18 to 80 years(mean: 54.4 years). MRIs were taken with a 1.5T superconductive system with a shoulder surface coil. MRGRT2-weighted images were recorded in the coronal oblique and sagittal oblique planes. A complete tear was diagnosed when a full thickness high intensity was observed in the rotator cuff, whereas a partial high intensity of the rotator cuff was considered as an incomplete tear. The size of the tear was measured in both MRI planes. We compared the size of the cuff tear in the MRI findings with the operative findings.
(Results) The operative findings confirmed complete tears in 59 patients, incomplete tears in 10 patients and no definite tear in 6 patients. On the other hand, MEI's showed complete tears in 54 patients, incomplete tears in 17 patients and impingiment syndrome in 4 patients. MRI demonstrated 89.8% sensitivity,90.5% specificity and 90.7% accuracy in the diagnosis of a complete tear. In the cases of incomplete tear, they were 90.8%,90.5%,88.0%, respectively. A linear regression analysis showed an excorrelation between the MRI assesment and the size of the tear revealed at operation on both planes.
(Conclusion) MRIs provided very useful pre-operative information on rotator cuff tears. In cases of complete tears, the size can easily be determined pre-operatively by an MRI. However, in a few cases of incomplete tears, there were hard to differentiate from the very small tears or the degenerative changes of the rotator cuff.
