Sonography and MR imaging of posterior tibial tendinopathy.

Abstract

The purpose of the study is to describe the appearance of the posterior tibialis tendon on MR imaging and high-resolution sonography with color and power Doppler imaging and to determine whether sonography is as accurate for diagnosing tendinosis as MR imaging. Fifteen healthy volunteers and 31 patients (44 tendons) who were clinically suspected of having posterior tibial tendinopathy were prospectively evaluated with MR imaging and sonography. On MR imaging, the normal tendon was elliptic on cross section and showed low signal intensity on all sequences. Minimal peritendinous enhancement and fluid were seen. On sonography, the tendon showed homogeneous longitudinal echogenic fibers. No flow was seen in or around the tendon. Tendinopathy was characterized by enhancement of the tendon on MR imaging (19/44 tendons); intratendinous flow on color Doppler sonography (16/44 tendons); increase in the anteroposterior diameter causing a rounding of the tendon (18/44 tendons); and inhomogeneity of the tendon (16/44 tendons on MR imaging and 21/44 tendons on sonography). Peritendinosis was characterized by peritendinous enhancement on MR imaging (29/44 tendons); flow on color Doppler sonography (20/44 tendons); and increased soft tissue (20/44 tendons on MR imaging and 27/44 tendons on sonography). When compared with MR imaging, the sensitivity and specificity of sonography for diagnosing tendinopathy were 80% and 90%, respectively, and for diagnosing peritendinosis were 90% and 80%. Addition of abnormal size to the structural abnormality criteria did not improve diagnostic ability. Sonography can be useful as the initial imaging study in evaluating abnormalities caused by posterior tibial tendinopathy.