Fifty-one cases were diagnosed as having incomplete tears of the rotator cuff with MR imaging. In eleven cases out of the 51, incomplete tears were surgically confirmed (four bursal-side tears, two joint-side tears, and five intratendinous tears). The other 40 cases did not undergo surgery. Ti- and T2-weighted images were obtained along the oblique coronal plane in a 1.5-T MR system. High signal lesions in the rotator cuff on T2-weighted images were observed in all the eleven cases. In one of the eleven, the high signal lesion had almost the full thickness of a rotator cuff, while in ten of the eleven, the high signal lesions had partial thicknesses. T2-weighted images mainly showed the intratendinous part of the tears regardless of the perforation. Slightly increased signal lesions on Ti-weighted images had the full thickness of the rotator cuff in all the eleven cases. Noninvasive MR imaging enabled us to diagnose incomplete tears of the rotator cuff.
