The purpose of this study was to evaluate the correlation between MRIs and the surgical findings of bursal side partial-thickness rotator cuff tear(BPRCT).53 shoulders, diagnosed as impingement syndrome or BPRCT at open surgery and 11 normal rotator cuff shoulders were studied. We evaluated the frequency of thickening sign and high intensity change of the rotator cuff in the MRI. According to the operative findings, patients were divided into four groups. BPRCT(group B), fibrillation of the rotator cuff surface(group F), subacromial impingement with an intact rotator cuff(group I), and a normal rotator cuff(group N) were 27.7,19, and 11shoulders respectively. The thickening sign of the rotator cuff was observed in 88.9%,57.1%,52.6%, and 9.1% of groups B, F, I, and N respectively. Furthermore, high intensity change of the rotator cuff was observed in 70.4%,14.3%,36.8%, and 0% of groups B, F, I, and N respectively. The sensitivity, specificity, and accuracy were 82.4%,63.3%, and 73.4% with a thickening sign and 58.8%,76.6%, and 67.2% with a high intensity change of the rotator cuff. The incidence of a thickening sign correlated with the degenerative change of the rotator cuff.. We concluded that the thickening sign of the rotator cuff in MRIs was useful in the screening of BPRCT.
