1 ACCURACY OF CONVENTIONAL IMAGING OF PENETRATING TORSO INJURIES IN THE TRAUMA RESUSCITATION ROOM Running head : IMAGING IN PENETRATING TRAUMA

Objectives: Chest X-ray (CXR), abdominal ultrasound, cardiac ultrasound and abdominal Xray are the most frequently used imaging modalities for radiological evaluation of patients with penetrating torso trauma. The aim of this study was to evaluate the accuracy of these imaging modalities. Methods: From January 2001 until January 2005, all consecutive patients with penetrating torso injuries presenting at the Emergency Department of a level 1 trauma center were included. Imaging modalities (chest/abdominal X-ray and abdominal/cardiac ultrasound), were compared retrospectively with a “gold standard” (i.e., CT or surgery within 2 hours after arrival) or outcome of conservative treatment. The accuracy of the imaging modalities was calculated. Results: 318 patients were included. Based upon 299 CXRs, the sensitivity for diagnosing pneumothorax, hemothorax and subcutaneous emphysema was 71%, 63% and 61%, respectively. The sensitivity of abdominal ultrasound (n=229) to detect free abdominal fluid and/or intra-abdominal injury was 65%. The specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the two imaging modalities to detect any of the diagnoses mentioned were  87%. Cardiac ultrasound (n=31) did not show any false positive or false negative results for detecting cardiac effusion. Pneumoperitoneum was not seen on abdominal X-ray in 8 of 11 patients with perforation of a hollow organ. Conclusions: Despite high specificity, PPV and NPV, a considerable number of lesions remain undetected following CXR and abdominal ultrasound due to moderate to inadequate sensitivity. Abdominal X-ray hardly provides additional information. Careful clinical monitoring of patients is mandatory, particularly when CT-scan or operative treatment is not indicated.