Helical CT of diaphragmatic rupture caused by blunt trauma

The purpose of this study was to determine the diagnostic sensitivity and specificity of helical CT with sagittal and coronal reformatted images in detecting diaphragmatic rupture after blunt trauma.

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. Findings 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. Sensitivity and specificity of helical CT were calculated on the basis of surgical findings and clinical follow-up.

Helical CT was performed preoperatively in 23 patients with diaphragmatic rupture (left, n = 17; right, n = 5; bilateral, n = 1). An additional 18 patients underwent helical CT to further evaluate suspicious findings seen on chest radiography at admission and were found to have an intact diaphragm. Sensitivity for detecting left-sided diaphragmatic rupture was 78% and specificity was 100%. Sensitivity for the detection of right-sided diaphragmatic rupture was 50% and specificity was 100%. The most common CT finding of diaphragmatic rupture was the collar sign, identified in 15 patients (sensitivity, 63%; specificity, 100%). Diaphragmatic discontinuity was seen in four patients.

Helical CT, especially with the aid of reformatted images, is useful in the diagnosis of acute diaphragmatic rupture after blunt trauma. Helical CT can be used to detect 78% of left-sided and 50% of right-sided injuries.