Managing radiation exposure in children--reexamining the role of ultrasound in the diagnosis of appendicitis.

PURPOSE

To assess the efficacy and accuracy of ultrasonography (US) and selective computed tomography (CT) in the diagnosis of acute appendicitis in children.

METHODS

A retrospective review of all ultrasound evaluations for appendicitis from July 1, 2003, to June 30, 2010, was conducted at two urban pediatric centers. Beginning in 2003, a multi-disciplinary diagnostic protocol was implemented to reduce radiation exposure employing US as the initial imaging modality followed by CT for non-diagnostic US studies in patients with an equivocal clinical presentation. The imaging, operative findings, and pathology of 802 patients (365 females, 437 males, age less than 18 years) with suspected appendicitis were reviewed. The sensitivity, specificity, predictive value, and negative appendectomy rate of the protocol were analyzed. A telephone survey was conducted of patients discharged without a diagnosis of appendicitis to evaluate the missed appendicitis rate.

RESULTS

Of the 601 pediatric appendectomies performed, a total of 275 (46%) were diagnosed by protocol. The selective protocol had a sensitivity of 94.2%, specificity of 97.5%, positive predictive value of 95.2%, and negative predictive value of 97.0%. The negative appendectomy rate was 1.82%, and the missed appendicitis rate was 0%. No patient discharged after only ultrasound evaluation without undergoing surgery reported missed appendicitis on the survey (41.7% response rate). Protocol use increased from 6.7% to 88.3%. US was the sole imaging modality in 630 of all 802 patients (78.6%).

CONCLUSIONS

US followed by selective CT for the diagnosis of acute appendicitis is useful and accurate. This has important implications in the reduction of childhood radiation exposure.