Prospective Examination of Patients Suspected of Having Appendicitis Using New Computed Tomography Criteria Including "Maximum Depth of Intraluminal Appendiceal Fluid Greater Than 2.6 mm"

Objective: The objective of this study was to perform prospective computed tomography (CT) examination of patients suspected of having appendicitis to determine whether our criteria (which include the new criterion "maximum depth of intraluminal appendiceal fluid greater than 2.6 min") are useful for improving sensitivity and/or specificity in comparison with conventional major criteria. Methods: Two hundred eighty consecutive patients older than 15 years old and suspected of having appendicitis were examined using CT We prospectively diagnosed appendicitis when a patient satisfied the following criteria (our criteria): (A) maximum appendiceal diameter greater than 6 nun in the presence or the absence of periappendiceal inflammation, (13) maximum depth of intraluminal appendiceal fluid greater than 2.6 mm, and (C) absence of an alternative lesion explaining the clinical manifestations. These patients were also prospectively examined using conventional major criteria (excluded criterion B from our criteria). Computed tomography findings were compared with the findings at surgery, pathology, and clinical follow-up. Results: Use of our criteria yielded a sensitivity of 97.3% (109/112), a specificity of 100% (168/168), and an accuracy of 98.9% (277/280) for the diagnosis of appendicitis. Using conventional major criteria, these values were 66.1% (74/112), 100% (168/168), and 86.4% (242/280) respectively, and sensitivity was lower than the value obtained using our criteria (P < 0.001 by the MacNemer test), although there is no significant difference in specificity between these criteria (P = 1 by the MacNemer test). Conclusions: Our criteria can improve sensitivity in comparison with conventional major criteria because our criteria enabled us to differentiate appendicitis without periappendiceal inflammation from a normal appendix.