Pelvic imaging in the stable trauma patient: is the AP pelvic radiograph necessary when abdominopelvic CT shows no acute injury?

The purpose of the study was to determine the utility of anteroposterior (AP) pelvic radiographs in stable trauma patients who will undergo or have undergone abdominopelvic CT as part of the initial trauma imaging evaluation. Radiology reports of all stable trauma patients who underwent both abdominopelvic CT and AP pelvic radiograph from 25 January through 30 April, 2003 were reviewed for findings of acute pelvic injuries. A total of 509 consecutive patients were included in this series. Of these, 449 patients (88.2%) had no acute pelvic injury revealed by abdominopelvic CT. CT showed 163 acute injuries in 60 patients. AP radiographs showed 132 acute injuries in 52 patients. No patients with a negative CT had an acute finding on the radiograph. There were eight false-negative pelvic radiographs (negative predictive value 98.25%). CT is highly accurate in excluding acute osseous pelvic injuries. In the stable trauma patient whose CT does not reveal an acute pelvic injury or who is scheduled to undergo an abdominopelvic CT as part of the initial imaging evaluation, the pelvic radiograph may be unnecessary.