Diagnostic comparison of X-ray plain film and 40-multidetector CT in dislocation of carpal bones

Objective: To study the imaging manifestations and detecting rates of dislocation of carpal bones on X- ray plain film and 40-multidetector CT (MDCT), to improve the diagnostic accuracy and to reduce the missed diagnosis and misdiagnosis. Materials and Methods: The X -ray plain films, MDCT, volume rendering (VR) and multiplanar reconstruction (MPR) of 21 patients with dislocation of carpal bones were retrospectively studied. 19 cases were male and two were female, mean age 31±7 years old (19-45 years). Dislocation was in left side in 14 cases, in right in seven cases. Result: Eight cases of lunate dislocation, 13 cases of perilunar dislocation, three cases of simple perilunar dislocation, four cases of perilunar dislocation per navicular bone. One case of perilunar dislocation per navicular and triangular bones, three cases of perilunar dislocation per triangular bones, two cases of perilunar dislocation per styloid process of radius. Among the cases with fracture of other carpal bones, the diagnosis of fractures of radial styloid process and navicular bones were correctly detected on X-ray plain film. But in three cases with fracture of triangular bone, the fractures were indetectable or the original place of the bone fragments were unable to determine on X-ray plain film, but could be correctly detected with MDCT and reconstruct technology. Conclusion: Diagnosis of dislocation of carpal bones can be correctly made with X-ray plain film in the most cases. But for the cases with fracture of carpal bones, especially with tiny fracture, X-ray plain film produces high rate of missed diagnosis. MDCT, VR and MPR can accurately show dislocations and fractures in three-dimension having high clinical value. (authors)