Patient gender-related performance of nonfocused helical computed tomography in the diagnosis of acute appendicitis.

OBJECTIVE: To determine the impact of patient gender on the performance of helical computed tomography (CT) in the diagnosis of acute appendicitis.

MATERIALS AND METHODS: From January 1, 1996 to December 31, 2000, 650 consecutive nonfocused helical abdominal CT scans were performed in adult patients presenting with acute lower abdominal pain. In general, most patients received both intravenous and oral contrast with 5-mm scan collimation through the lower abdomen and pelvis; details regarding technique and overall accuracy have been published previously. We subanalyzed results with respect to patient gender-related differences, especially in false-positive and false-negative cases. A chi2 analysis was performed to determine if significant gender-related differences were present in major or minor CT diagnostic criteria for acute appendicitis, extra-appendiceal findings, sensitivity, specificity, and accuracy.

RESULTS: Of the 650 patients, 552 had adequate clinical follow-up. The sensitivity for diagnosing acute appendicitis was 100% (65/65) in men and 93.6% (74/79) in women (P < 0.05); specificity was 96.2% (130/135) in men and 98.9% (272/275) in women (P > 0.05); and accuracy was 97.5% (193/198) in men and 97.6% in women (346/354) (P > 0.05). A thickened appendix and periappendiceal stranding were seen in 92.1% of men and 84.5% of women (P = 0.15) All 5 false-negative results were in thin women. In patients without acute appendicitis, CT was able to provide a relevant alternative diagnosis in 183 of 272 women (67.3%) and 81 of 130 men (62.3%) (P > 0.05).

CONCLUSION: Nonfocused helical CT was highly accurate for diagnosing acute appendicitis in both men and women, although there was a slight but significant decrease in sensitivity in thin women.