Helical CT of diaphragmatic rupture caused by blunt trauma

OBJECTIVE. The purpose of this study was to determine the diagnostic sensit ivity and specificity of helical CT with sagittal and coronal reformatted i mages in detecting diaphragmatic rupture after blunt trauma. MATERIALS AND METHODS. Chest and abdominal helical CT scans obtained in 41 patients with suspected diaphragmatic injury after major blunt trauma were reviewed by three observers who were unaware of surgical findings. Coronal and sagittal reformatted images were reviewed for each patient as well. Fin dings consistent with diaphragmatic injury, such as waistlike constriction of abdominal viscera (i.e., the "collar sign"), intrathoracic herniation of abdominal contents, and diaphragmatic discontinuity were recorded. Sensiti vity and specificity of helical CT were calculated on the basis of surgical findings and clinical follow-up. RESULTS. Helical CT was performed preoperatively in 23 patients with diaphr agmatic rupture (left, n = 17; right, n = 5; bilateral, n = 1). An addition al 18 patients underwent helical CT to further evaluate suspicious findings seen on chest radiography at admission and were found to have an intact di aphragm. Sensitivity for detecting left-sided diaphragmatic rupture was 78% and specificity was 100%. Sensitivity for the detection of right-sided dia phragmatic rupture was 50% and specificity was 100%. The most common CT fin ding of diaphragmatic rupture was the collar sign, identified in 15 patient s (sensitivity, 63%; specificity, 100%). Diaphragmatic discontinuity was se en in four patients. CONCLUSION. Helical CT, especially with the aid of reformatted images, is u seful in the diagnosis of acute diaphragmatic rupture after blunt trauma. H elical CT can be used to detect 78% of left-sided and 50% of right-sided in juries.