Ultrasound for the detection of foreign bodies in human tissue.

Abstract

To determine the accuracy of detection of wood and plastic foreign bodies in human tissue by relatively inexperienced clinicians using typical ultrasound equipment. Uniform wood and plastic foreign bodies were placed through small punctures into recently amputated human legs. Identical control punctures contained no foreign bodies; the sequence of foreign bodies and controls for the puncture sites was randomized. A second blinded investigator scanned each puncture site with a 7.5-MHz ultrasound probe to determine the presence or absence of foreign material. Eighty punctures were scanned. Ultrasound detected 44 of 53 foreign bodies (83% sensitivity). Wood foreign bodies were detected 25 of 27 times (93%) and plastic foreign bodies 19 of 26 times (73%; P = 13). Overall, there were 11 false-positive readings (59% specificity). Ultrasound is imperfect but may be useful in screening for superficial foreign bodies in human tissue. Clinical utility in the ED setting remains to be tested.