Can low-dose abdominal CT replace abdominal plain film in evaluation of acute abdominal pain?

BACKGROUND Non-contrast computed tomography (NCT) has become an important diagnostic tool in acute abdominal pain, but the drawback is the increased radiation dose compared to abdominal plain film (APF). PURPOSE To evaluate whether NCT, including low-dose computed tomography (LDCT, using 50 mAs), provides more diagnostic information than APF in patients presenting with acute non-traumatic abdominal pain and if the use of CT can reduce the total number of additional radiograms. A second aim was to compare the diagnostic outcome between standard-dose computed tomography (SDCT) and LDCT. MATERIAL AND METHODS During 2000, 2002, and 2004 a total of 222 patients were retrospectively reviewed, and 86 patients had APF, 60 had SDCT, and 76 had LDCT. The radiological report of each patient was compared with the final diagnosis obtained from the medical record within 30 days. Additional radiograms were registered, and a total radiation dose excluding or including APF or NCT was calculated. RESULTS NCT gave a correct diagnosis in 50%, compared to 20% with APF (P < 0.001). The total number of additional radiograms was substantially lower in the computed tomography (CT) group compared to the APF group (P < 0.001), and the average sum of radiation dose was similar for APF and LDCT. CONCLUSION NCT was found to be significantly better at providing diagnostic information than APF in patients presenting with acute abdominal pain. It reduced the number of additional radiograms, but the total patient dose remained somewhat higher in the CT group even when using LDCT with 50 mAs.