Doppler ultrasound accurately screens patients with appendicitis.

Ultrasound (US) has been reported as a useful aid to increase the sensitivity and specificity of the diagnosis of appendicitis. To determine the accuracy of US, we performed a prospective study of patients evaluated in the emergency department for acute appendicitis. US results of 125 consecutive patients over an 11-month period were correlated with operative and pathologic findings and clinical follow-up. The appendix was visualized as a noncompressible structure in 19 patients, and 18 had appendicitis (95%). Ten of the 12 patients with abnormal Doppler activity in the appendix had appendicitis (83%). Conversely, the appendix could not be visualized in 102 patients, and 100 did not have appendicitis (98%). One hundred five of the 113 patients (93%) with absent abnormal Doppler activity did not have appendicitis. Ninety-four of the 125 patients had neither visualization of the appendix nor abnormal activity, and 2 had appendicitis. The sensitivity of US for appendicitis was 90 per cent, and the specificity was 94 per cent. Visualization of the noncompressible appendix or abnormal Doppler activity strongly suggests appendicitis. More importantly, the absence of both of these ultrasonographic findings defines a patient subset that may be safely discharged from the emergency department without admission.