[Routine sonography in suspected appendicitis. A trial of 24-hour screening at a general hospital]

A prospective study was conducted to determine the diagnostic value of sonography in suspected acute appendicitis. From September 1987 until May 1988, the end of the study, 152 patients suspected of having "acute appendicitis" were admitted to hospital. In contrast to other recently published studies conducted by a few highly qualified examiners, we dimed at determining whether this method is useful as a 24-hour-screening performed ba y number of more or less qualified examiners. In the beginning, the patients were examined with a 3.5 MHz scanner, later on exclusively with 5 MHz linear and sector scanners. 150 cases could be evaluated, 96 of which underwent surgery. We found 35 sonographically correct results, 89 correctly negative, 4 false positive and 13 false negative diagnoses. This means a sensitivity of 73% and a specificity of 96% for the sonographical diagnostic method. In 20 cases (13%) sonography led to other diagnoses. A large majority of these findings can be detected by less experienced examiners. The goal of a 24-hour-screening could not be reached because there a competent examiner was not always available at night. It became clear that clinically obvious cases do not require sonographic conformation. The value of sonography lies with doubtful cases of appendicitis: if the ultrasound examination is negative, appendectomy can be postponed; if sonography leads to other differential diagnoses, appropriate therapy can be started immediately.