Background: Acute abdominal pain is a common complaint in an emergency setting. An immediate and precise diagnosis is necessary for reducing morbidity and mortality. Several studies have reported that CT scan increases diagnostic accuracy for patients with acute abdominal pain. This study was designed to evaluate the sensitivity, specificity and accuracy of spiral CT scan compared to that of abdominal ultrasound and plain radiography. 

Methods: We assessed the data of 91 consecutive patients, including 45 males and 46 females, ranging in age from 8 to 84 years (mean age 52.38 years) presenting to the emergency department of Sina Hospital, Tehran, Iran, with acute non-traumatic abdominal pain during the years 2003-2005. All patients underwent spiral CT scanning; in addition, sonography and plain radiography were performed for 66 and 64 of the patients, respectively. The sensitivity, specificity and accuracy were calculated and compared, based on the final diagnosis, which was established with surgical, pathologic, and clinical follow-up. The data was analyzed by SPSS 13.0 software.

Results: Among the 91 patients examined, CT scan was reported to be normal in 15 patients (16.5%). The most common CT findings were aortic aneurysm (12.1%), pancreatitis (9.9%), ovarian cyst (7.7%), intestinal distension (7.7%), and hepatic cyst (7.7%). The overall sensitivity, specificity, and accuracy of unenhanced spiral CT were 92.2%, 92.86%, and 92.3%, respectively, whereas those of plain radiography were 13.2%, 72.7%, and 23.4%, respectively, and ultrasound 73.2%, 90%, and 75.7%, respectively.

Conclusions: This study suggests that plain radiography is an insensitive technique in the evaluation of nontraumatic acute abdominal pain presenting in the emergency department. Unenhanced spiral CT is accurate for adult patients with nontraumatic acute abdominal pain and should be considered as an alternative to radiography as the initial imaging modality.