Shoulder impingement syndrome: sonographic evaluation.

A method of shoulder sonography in which lateral and anterior elevation of the arm is used during scanning was demonstrated to be effective in cases of suspected impingement syndrome. The value of the method lies in its ability to demonstrate fluid collection in the subacromial-subdeltoid bursal system, with gradual distention of the bursa and lateral pooling of fluid to the subdeltoid portion while the arm is elevated. In 102 of 381 patients studied, surgical diagnosis was available for correlation. Among this group there were seven false-negative and three false-positive sonographic findings. A comparison of sonographic with surgical findings demonstrated a sensitivity of 81% and a specificity of 95% in stages I-III, and a sensitivity of 71% and a specificity of 96% in early stages I and II of the impingement syndrome. The results of dynamic shoulder sonographic examination with fluoroscopic radiography provide valuable information in patients with suspected early-stage impingement syndrome.