MR DIAGNOSIS OF ROTATOR CUFF TEARS OF THE SHOULDER - VALUE OF USING TS-WEIGHTED FAT-SATURATED IMAGES

OBJECTIVE. The purpose of this study was to compare the use of fat-sat urated T2-weighted spin-echo MR imaging with that of conventional T2-w eighted spin-echo MR imaging to detect full- and partial-thickness tea rs of the rotator cuff of the shoulder, using arthroscopy as the stand ard for the diagnosis. SUBJECTS AMD METHODS. Forty-nine consecutive pa tients with shoulder pain who had both MR imaging and arthroscopy of t heir affected shoulders were studied. The study group consisted of 10 patients with full-thickness tears of the rotator cuff, 20 with partia l-thickness tears of the rotator cuff, and 19 with intact rotator cuff tendons proved arthroscopically. All patients had T1-weighted, conven tional T2-weighted, and fat-saturated T2-weighted MR images obtained i n a plane slightly oblique to the coronal plane along the long axis of the supraspinous tendon. The images were divided into two sets, one i ncluding both T1-weighted and conventional T2-weighted images, the oth er including T1-weighted and fat-saturated T2-weighted images, Two mus culoskeletal radiologists reviewed each set of MR images in a blinded fashion. The reviewers were asked to decide whether the rotator cuff s howed a full-thickness tear, a partial-thickness tear, or no tear on e ach set of images. In the case of partial-thickness tears, the reviewe rs were asked to indicate which surface (bursal or joint) of the rotat or cuff was affected. These data were correlated with the arthroscopic findings and with each other using McNemar and kappa analysis. RESULT S. Detection of full-thickness tears was excellent for both reviewers using either imaging technique. However, when the fat-saturated techni que was used, the sensitivity increased significantly, from 80% to 100 %. Detection of partial-thickness tears was poor with conventional spi n-echo MR imaging (15%). Although significantly improved when fat satu ration was used (35%), detection rates were still lower than rates rep orted in the literature. Identification of the torn surface of the rot ator cuff was correct in 50% of cases in which partial-thickness tears were successfully identified. Fat saturation decreased the specificit y of identification of both partial and full-thick ness tears of the r otator cuff but significantly increased the specificity with which int act rotator cuffs were identified. CONCLUSION. Use of the fat-saturati on technique improved detection of both full-thickness and partial-thi ckness tears of the rotator cuff on MR images compared with standard s pin-echo imaging techniques. Despite this improvement, detection of pa rtial-thickness tears was poor with both techniques. Furthermore, corr ect identification of which surface of the rotator cuff was torn in pa tients with partial tears was nearly random.