Integration of ultrasound findings and a clinical score in the diagnostic evaluation of pediatric appendicitis.

OBJECTIVE: To determine the predictive value of ultrasonography (US) for appendicitis in children when combined with clinical assessment based on the Pediatric Appendicitis Score (PAS). STUDY DESIGN: Observational study of children aged 3-18 years who had an US examination for possible appendicitis. A PAS was calculated on the basis of historical elements, examination, and laboratory studies and was used to classify patients into 3 risk groups (low, medium, high). The predictive value of the PAS for appendicitis was calculated and stratified by the result of the US (positive, negative, or equivocal). RESULTS: A total of 728 children with a median age 11.7 (IQR 7.8-14.9) years were studied; 29% had appendicitis. The negative predictive value of US decreased with increasing PAS-based risk assignment: low risk 1.00 (95% CI, 0.97-1.00), medium risk 0.94 (0.91-0.97), and high risk 0.81 (0.73-0.89). With increasing PAS, the positive predictive value increased: low risk 0.73 (0.47-0.99), medium risk 0.90 (0.82-0.98), and high risk 0.97 (0.95-1.0). Among children with equivocal ultrasound results, the proportion with appendicitis ranged from 0.09 (0.0-0.19) for low-risk patients to 0.47 (0.33-0.61) among for high-risk patients. CONCLUSION: Ultrasound findings in children with possible appendicitis should be integrated with clinical assessment, such as a clinical score, to determine next steps in management. Rates of false-negative US increase with increasing PAS, and false-positive US results occur more often with lower PAS. When discordance exists between US results and the clinical assessment, serial examinations or further imaging are warranted.

Advanced radiologic imaging for pediatric appendicitis, 2005-2009: trends and outcomes.

OBJECTIVES: To examine the variability in the use of computed tomography (CT) and ultrasound (US) for children with appendicitis and identify associations with clinical outcomes, and to demonstrate any trends in diagnostic imaging between 2005 and 2009. STUDY DESIGN: This was a retrospective review of children evaluated for appendicitis in an emergency department between 2005 and 2009 using an administrative database of 40 pediatric institutions in the United States. Imaging utilization by institutions was studied for association with 3 clinical outcomes. RESULTS: A total of 55 238 children with appendicitis were studied. Utilization of CT and US varied widely across institutions, with medians of 34% (IQR, 21%-49%) for CT and 6% (IQR, 2%-26%) for US. Increased use of US or a combination of CT and US (but not of CT use alone) was associated with a lower negative appendectomy rate. Imaging was not associated with other clinical outcomes. In children with appendicitis, the use of US has increased since 2007, whereas that of CT has decreased. CONCLUSION: There is considerable variation in the use of CT and US for children with appendicitis at major pediatric institutions. At the institutional level, increased use of US or combined US and CT is associated with a lower negative appendectomy rate. Despite the better diagnostic accuracy of CT compared with US, the use of CT is decreasing.