Surgical validation of unenhanced helical computed tomography in acute appendicitis.

Background: Surgery for pain in the right lower quadrant of the abdomen remains a clinical dilemma. This prospective study assessed the accuracy of preoperative unenhanced helical computed tomography (CT) in the evaluation of patients with suspected acute appendicitis.

Methods: One hundred and three adult patients with suspected acute appendicitis underwent unenhanced helical CT of the abdomen. Subsequently, all patients underwent laparoscopic inspection of the abdominal cavity by a surgeon who was blinded to the diagnosis suggested by CT. Patients underwent appropriate surgical therapy accordingly. Follow-up was at least 6 weeks.

Results: Appendicitis was diagnosed by CT in 83 patients (80.6 per cent). Acute appendicitis was identified during laparoscopy in 87 patients (84.5 per cent). Prospective interpretation of CT images yielded a sensitivity of 95.4 per cent and a specificity of 100 per cent for the diagnosis of acute appendicitis. There were four false-negative scans. In 12 of 20 patients without signs of appendicitis on CT, the scan established the presence of other pathology. At operation no additional pathology was observed in this group and all other diagnoses proved to be correct.

Conclusion: Plain helical CT in patients with suspected acute appendicitis provides an accurate diagnosis without the disadvantages of contrast enhancement.