Normal anatomy and pathologic conditions of ankle tendons: current imaging techniques.

Radiologic assessment of tendon injuries requires familiarity with normal anatomy and the capabilities of available imaging modalities. Tenography, less commonly used nowadays, does not allow direct visualization of tendons, so that partial ruptures and longitudinal splits may go undetected. Ultrasonography can depict tenosynovitis, tendinitis, and complete tendon rupture of the Achilles tendon, but the other tendons are difficult to visualize with this technique. Magnetic resonance (MR) imaging is superior to computed tomography (CT) in the depiction of tenosynovitis and peritendinitis, tendinitis, tendon rupture, and tendon dislocation and subluxation. CT can demonstrate these abnormalities, but accompanying scar tissue or edema, early changes of tendon degeneration, and small amounts of inflammatory fluid are difficult to differentiate with this technique. CT is superior for demonstrating calcifications, convex retromalleolar groove, bone fragments, or spurs that complicate tendon dislocation and rupture. Although the authors prefer MR imaging, they caution that all of the modalities are not always specific and that differentiation between closely related processes such as tendinitis and early tendon rupture is difficult.