The comparative accuracy of radiolucent foreign body detection using ultrasonography

The purpose of this prospective study was to determine the accuracy of ultrasonography in detecting radiolucent foreign bodies and to compare the performance of three newly trained emergency physicians with two experienced ultrasound technologists and one radiologist. One hundred four chicken thighs were penetrated with a needle-driver, half of them embedded with a 1.5 cm toothpick. An 8.0 MHZ linear array ultrasound probe was used to detect the presence or absence of the foreign body. The overall accuracy (95% confidence interval [CI]) was 82% (79, 85); sensitivity 79% (74, 83), specificity 86% (82, 90), positive predicative value (PPV) 85% (81, 89), and negative predicative value (NPV) 80% (76, 84). The accuracy (95% CI) of the radiologist was 83% (75, 90); of the ultrasound technologists was 85% (80, 90); and of the emergency physicians was 0% (76, 85). The difference in accuracy among the three types of personnel was not statistically significant. Ultrasonography is an accurate modality in detecting radiolucent foreign bodies. Emergency physicians can be trained to provide a degree of accuracy comparable with more experienced ultrasonographers. (Am J Emerg Med 2000;18:401-403.