The role of abdominal computed tomography scanning in patients with non-traumatic abdominal symptoms

To describe the non-traumatic clinical settings in which abdominal computed tomography (CT) is used and to determine its diagnostic utility.

A retrospective descriptive study of consecutive non-traumatic adult patients who underwent abdominal CT in a university hospital emergency department (ED). Radiology reports and patient charts were reviewed. The indication for each CT was determined by two reviewers. Indications were described as specific (e.g. "rule-out" appendicitis) or non-specific (e.g. abdominal pain). CT results were classified as positive, negative (normal or no new information) or indeterminate (technical limitations). For those with specific indications, positive results were further subdivided into supportive (of the clinical suspicion) or non-supportive (abnormal but suggesting an alternative diagnosis). The clinical course and results of subsequent diagnostic procedures were used to confirm CT results for admitted patients. Incidental CT findings were recorded.

177 patients were entered; mean age was 58 years; 48% were men. The most frequent indications ("rule-outs") were aortic disorders (23%), abscess (16%), and diverticulitis (14%). In patients with specific indications (n=160), 44% of the CT results supported the indication, 13% suggested an alternative diagnosis (non-supportive), 41% were negative, and 3% were indeterminate. In admitted patients (n=129), CT findings were contradicted in 6%.

Adult ED patients undergo abdominal CT for a variety of non-traumatic indications. Findings in less than half support the pre-test clinical suspicion and an alternative previously unsuspected diagnosis is suggested in 13%. Follow-up is inconsistent with CT results in a small but significant number of cases.