CT Scan in the Diagnosis of Acute Appendicitis: Help or Hindrance?

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Objective: The use of preoperative abdominal Computerized Tomography (CT) in the evaluation of presumed appendicitis has improved diagnostic accuracy and reduced negative appendectomy rates. We sought to identify the effect of the increased use of CT on the time to operative intervention and perforation rates at a single institution.

Method: Patients who had appendectomies for presumed appendicitis between January 2000 and May 2006 were identified. Patients who had preoperative CT were recognized as was the type of CT technology used at the time of presentation (single slice, 4-slice or 16-slice). The length of time between presentation to the emergency department and the operative procedure, and histopathology reports were reviewed.

Results: In the studied period, 1416 appendectomies were performed for presumed appendicitis. Preoperative CT was performed in 56% of patients(30.2% in the single-slice period, 55.8% in 4-slice period and 78.6% in16-slice period.) The average time between presentation and commencement of surgery was increased in patients who had preoperative CT - 12.2 ± 9.8 hours vs. 7.7 ± 6.3 hours in patients without preoperative CT. This was statistically significant(p < .001) The results were similar in the single slice, 4-Slice and 16-slice periods. There was also a statistically significant increase in the perforation rate in patients with preoperative CT (16.4% vs. 6.0%; p < 0.01). Preoperative CT was noted to be an independent risk factor for perforation by multivariate analysis - odds ratio of 3.16 (95% CI 2.09-4.77)

Conclusion: Preoperative CT improves preoperative diagnostic accuracy for acute appendicitis but is associated with a delayed time to surgery and an increase in the perforation rate. Its use should be more selectively applied for these reasons.


This poster was presented at the Society for Surgery of the Alimentary Tract (SSAT), Digestive Disease Week, San Diego, CA, May 17-21, 2008.