Computed tomography in acute abdominal pain: an overused investigation?

The use of computed tomography (CT) for the evaluation of patients presenting to the emergency department (ED) with acute abdominal pain has increased. We set out to investigate its effectiveness.

A prospective study conducted at a tertiary referral centre between August and September 2012, utilizing a questionnaire completed by the ordering doctors. Patients with acute abdominal pain who underwent an abdominal CT scan were included in the study, excluding those with a history of recent abdominal trauma or abdominal, pelvic, groin or scrotal surgery.

Of the 260 patients undergoing an abdominal CT scan for the investigation of acute abdominal pain, 60 had questionnaires completed. Fifty-seven per cent of abdominal CT scans were ordered by an ED registrar or consultant. Sixty-five per cent of patients were not discussed with the surgical team prior to ED staff ordering the CT scan. 'To confirm clinical suspicion' and 'to rule out sinister aetiology' were the most important reasons for ordering an abdominal CT. In 54% of cases, there was a change in primary diagnosis post CT scan and in 50% of patients, a change in disposition. Diagnostic confidence in the primary diagnosis did not change significantly post-CT scan. There was no significant difference between which group ordered a CT scan and the probability that the scan showed nil acute pathology.

Abdominal CT scans frequently changed the clinical diagnosis and patient disposition. Twenty-three per cent of patients had no identifiable cause on CT scan for their acute abdominal pain.