Clinical value of ultrasonography in the detection and removal of radiolucent foreign bodies.

A series of 39 consecutive patients with a suspected retained foreign body in the hand and in whom standard soft issue radiographs were negative were examined by real-time, high-resolution ultrasound scan. At operation 20 patients had radiolucent foreign bodies (18 wood, 2 thorns) removed. Ultrasound scan correctly localized 19 of the foreign bodies before surgery and failed to detect one. No foreign body was found in 19 patients. Ultrasound scan falsely predicted the presence of a foreign body in two of these cases. High-resolution ultrasound scanning is a sensitive, accurate technique for diagnosing foreign bodies which are otherwise difficult to demonstrate by conventional radiographic techniques, and provides accurate three-dimensional localization of the object which is of value to the surgeon at operation.