Power Doppler sonography in tenosynovitis: significance of the peritendinous hypoechoic rim

The aim of this study was to evaluate the ability of power Doppler sonography to distinguish between hypoechoic fluid and synovium in patients with suspected tenosynovitis. Gray scale sonography and power Doppler sonography were performed on 26 tendons in 24 patients with tenosynovitis and 30 tendons in five asymptomatic volunteers. Peritendinous blood flow was graded on a scale of 0 to 3 and the percentage of the hypoechoic rim that contained blood flow was also noted. In the symptomatic group, flow was demonstrated in more than 50% of the peritendinous hypoechoic rim in 17 of 26 tendons. A positive correlation was found between the power Doppler sonographic grade and the percentage of the rim that had flow. These results suggest that a significant proportion of the hypoechoic rim probably represents vascularized synovium rather than complex fluid.