Diagnosis of acute appendicitis with unenhanced helical CT: a study of 130 patients.

The aim of this study was to determine the sensitivity, specificity, and diagnostic accuracy of helical computed tomography (CT) without oral, intravenous, or rectal administration of contrast material in confirming the diagnosis of acute appendicitis in patients with suggestive clinical and laboratory findings. One hundred and thirty patients with suspected acute appendicitis underwent an unenhanced helical CT scan. Scans were obtained in a single breath-hold from the level of umbilicus to the pubic symphysis using a 5-mm collimation. Oral, intravenous, or rectal contrast materials were not used. The criteria for diagnosis of acute appendicitis included an enlarged diameter of appendix more than 6 mm with associated periappendiceal inflammation. The results yielded a sensitivity of 94.7%, a specificity of 91.7%, an accuracy of 93.8%, a positive predictive value of 96.7%, and a negative predictive value of 86.8%. Unenhanced helical CT accurately diagnoses acute appendicitis, and it protects the patients from unnecessary further time-consuming diagnostic procedures, the risks associated with contrast material administration, and unnecessary surgical interventions.