Changing roles of computed tomography in diagnosing acute appendicitis in emergency rooms.

Background: We used the Taiwan National Health Insurance Database for analysis and statistics to investigate the role of computed tomography (CT) in diagnosing acute appendicitis.
Materials and Methods: All 10 046 patients with acute appendicitis were selected and categorized into two groups based on those who did and did not receive CT 3 days before acute appendicitis diagnosis: non-CT and CT groups. A noteworthy outcome was the incidence of peritonitis within 90 days after diagnosis of acute appendicitis.
Results: The rate of using CT for patients with acute appendicitis increased considerably from 7.9% to 52.9% from 2000 to 2010. The peritonitis incidence rates were 3.54% and 10.7% in the non-CT and CT groups, respectively. Patients who received CT on the same day exhibited a 3.8-fold higher risk of peritonitis than did those in the non-CT group. Those who underwent CT before diagnosis of acute appendicitis exhibited no significant difference of peritonitis risk when compared with those in the non-CT group. The CT group patients were hospitalized 2.19 days longer than the non-CT group patients. Patients who received CT before and on the same day were hospitalized 1.31 and 2.43 days longer than those who did not undergo CT.
Conclusion: Patients who underwent CT exhibited higher risks of peritonitis and longer hospital stays compared with those who did not. Moreover, patients who received CT on the same day of operation exhibited a higher risk of peritonitis than those who underwent CT 1 or 2 days before operation.
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