[Suspected acute appendicitis. Role of enhanced helical computed tomography. Prospective study of 100 patients]

To assess the diagnosis accuracy of helical computed tomography (CT) in patients with suspected appendicitis.

This prospective study included 100 consecutive patients hospitalized for suspected appendicitis. There were 57 men and 43 women with a median age of 30 years (range: 17-91). An enhanced helical CT was performed at admission, without digestive opacification. Four criteria were interpreted as positive signs for appendicitis: appendix enlarged > or = 7 mm, right lower quadrant inflammation, stercorolith, and peri-appendicular collection. The patient was managed by the surgeon without knowing the result of CT. The final diagnosis was made pathologically.

Eighty-one patients were operated on laparoscopically for suspected appendicitis. Intraoperative diagnosis was corrected in three cases and 78 appendectomies were performed (73 histological appendicitis, six normal appendix). Final diagnosis was a medical disease in 19 patients. The findings of 67 CT were interpreted as positive (63 true positive and four false positive) and the findings of 33 CT were interpreted as negative (24 true negative, nine false negative). Sensitivity was 87%, specificity was 86%, positive predictive value was 94%, and negative predictive value was 73%. If the nine false negative cases with minimal lesions at pathological examination were considered as true negative, the rates would be 100%, 89%, 94%, 100%, respectively.

Enhanced helical CT is a good imaging diagnostic tool for suspected appendicitis. It may reduce the number of patients admitted for observation and decrease the rate of negative appendectomy.