Does enteral contrast increase the accuracy of appendicitis diagnosis?

Several approaches traditionally have helped opacify the bowel when computed tomography (CT) is used to diagnose appendicitis. With the development of multidetector row CT (MDCT), the need for enteral contrast agents is less obvious. Purpose The objective of this study was to evaluate retrospectively the accuracy of MDCT demonstration of appendicitis using enteral contrast agents.

We reviewed radiologic reports of all 246 adult patients with suspected appendicitis who underwent 16-slice MDCT during 2005-2006 at our department. The use of enteral contrast agents and the route of administration were documented by one investigator. A radiologist evaluated whether the responses in the reports were consistent with diagnosis of appendicitis. The accuracy of the radiologic reports was assessed using the results of surgery, histopathology and 3 to 21 months of follow-up.

Of patients studied, 14.6% received no enteral contrast agent, 8.5% received both oral contrast and rectal contrast (enema), 46.7% received oral contrast and 30.1% received rectal contrast enemas. The accuracies for the CT diagnosis of appendicitis with different combinations of agents ranged from 95% to 100%, with no significant difference among groups.

Our study shows that the accuracy for diagnosis of appendicitis by abdominal 16-slice MDCT is high regardless of enteral contrast use. Therefore, further use of enteral contrast agents for CT diagnosis of appendicitis in adults cannot be recommended.