BACKGROUND: The objective of this study was to determine if routine use of computed tomography (CT) for the diagnosis of appendicitis is warranted.

METHODS: During a one-year study period, all patients who presented to the surgical service with possible appendicitis were studied. One hundred eighty-two patients with possible appendicitis were randomized to clinical assessment (CA) alone, or clinical evaluation and abdominal/pelvic CT. A true-positive case resulted in a laparotomy that revealed a lesion requiring operation. A true-negative case did not require operation at one-week follow-up evaluation. Hospital length of stay, hospital charges, perforation rates, and times to operation were recorded.

RESULTS: The age and gender distributions were similar in both groups. Accuracy was 90% in the CA group and 92% for CT. Sensitivity was 100% for the CA group and 91% for the CT group. Specificity was 73% for CA and 93% for CT. There were no statistically significant differences in hospital length of stay (CA = 2.4 +/- 3.2 days vs. CT = 2.2 +/- 2.2 days, p = 0.55), hospital charges (CA = 10,728 US dollars +/- 10,608 vs. CT = 10,317 US dollars +/- 7,173, p = 0.73) or perforation rates (CA = 6% vs. CT = 9%, p = 0.4). Time to the operating room was shorter in the CA group, 10.6 +/- 8.4 h vs. CT, 19.0 +/- 19.0 h (p < 0.01).

CONCLUSIONS: Clinical assessment unaided by CT reliably identifies patients who need operation for acute appendicitis, and they undergo surgery sooner. Routine use of abdominal/pelvic CT is not warranted. Further research is needed to identify sub-groups of patients who may benefit from CT. Computed tomography should not be considered the standard of care for the diagnosis of appendicitis.