[MSCT diagnosis of foot and ankle tendon injury]

To study the MSCT features and diagnosis of foot and ankle tendon injury and improve the recognition to avoid the missed.

From January 2009 to December 2010, 32 patients suspected of foot and ankle tendon injury were enrolled and included 24 males and 8 females with an average age of 43 years ranging from 23 to 68 years. All patients had pain, tenderness, swelling or disfunction in the diseased foot and were finally confirmed with surgery, MRI, contralateral contrast and followed-up. The MSCT was performed with a multi-detector CT scanner (Emotion 6; Siemens) within 7 days after injury. Two experienced radiologists evaluated the tendon abnormalities before told the outcome.

With 5 patients lost, the final study included 27 patients. Thirty-one tendon injuries were finally confirmed in 23 cases. Thirty-five tendon abnormalities were diagnosed on CT images among all 243 tendons but 4 of them were misdiagnoses. The CT overall diagnostic sensitivity, specificity, and accuracy was 88.8% (31/35), 98.1% (208/212), and 98.4% (239/243). Eleven tendon dislocations showed as the tendon partially or completely off the tendon groove. Thirteen tendon entrapment showed no less than half section of the tendon embedded the fracture in the axial images, and 7 tendons located in the fracture gap or 6 tendons closely related with widened fracture in VR images (2 misdiagnosis). Four bone chip insertion showed the chip inserted in the tendons both in the axial images and VR images (1 misdiagnosis). Four tendon ruptures showed discontinuity and shortening of the tendon (1 misdiagnosis). Three tendon injuries showed thickening, density reduction and blurring of tendons, and misty surrounding fat space.

With comprehensive MSCT examination (thin-slice scanning and volume rendering) of foot and ankle, the tendon dislocation, tendon entrapment, bone chip intercalation, and tendon rupture/injury could be confidently diagnose.