Fluid Signal Intensity That Mimicked A Supraspinatus Tendon Tear In A Subacromial Injected Shoulder: A Case Report

as a diagnostic tool as well as a therapeutic tool for shoulder pain due to rotator cuff pathology. Thus, many patients who undergo shoulder imaging evaluation have a history of subacromial injection. Several studies have been done to evaluate the accuracy of subacromial injection. Most studies have revealed not only the difficulty of an accurate injection into the subacromial bursa, but also that the injected material infiltrated into other regional structures even when an accurate injection was done into the subacromial space. Bergman and Fredericson (1) determined the rate of a false positive increased signal on the T2-weighted MR sequences after a subacromial injection by obtaining serial MRI scans before and after subacromial injection. They found that the bursal and extrabursal fluid is resolved or decreased on MRI by 3 days after the injection. They recommended a 3-day delay after shoulder injection for performing MRI to prevent misinterpretation of the signal changes. We report here on a case that mimicked a full-thickness tear of the supraspinatus tendon on conventional MRI one month after subacromial steroid injection and the tendon was intact as confirmed by arthroscopic examination and postoperational ultrasonography (USG). J Korean Soc Radiol 2010;63:271-274