Appendicitis is the most common pediatric surgical emergency accounting for 5% of urgent pediatric outpatient visits for abdominal pain. Computed tomography (CT) and ultrasonography (US) are two imaging modalities used in the diagnostic evaluation of acute appendicitis. Both have decreased the incidence of negative appendectomy results. It is well known that CT has greater diagnostic accuracy than US for diagnosing acute appendicitis, but there is concern over long-term cancer risk, with routine use of CT in children.
Is CT or US more accurate in the diagnosis of acute appendicitis?
Doria AS et al. US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta-Analysis. Radiology 2006 Oct; 241(1): 83–94. PMID: 16928974
duration of abdominal pain increase accuracy of ultrasound?
Bachur RG et al. The Effect of Abdominal Pain Duration on the Acuracy of Diagnostic Imaging for Pediatric Appendicitis. Ann Emerg Med 2012; 60: 582–90. PMID:22841176
The advantages of US include low cost, lack of radiation, and dynamic information with graded compression. The advantages of CT include: no operator dependency, delineation of extent of disease (i.e. perforated appendicitis), easier visualization, unchanged quality of imaging over time, and multiplanar reconstruction of images. Based on the above study, if symptoms have been present for >48 hours, US is just as good as CT for ruling out the diagnosis of acute appendicitis.
The decision to obtain an US vs CT for children with suspected appendicitis remains a challenge. On a case by case basis, one should consider the following 4 major goals in care:
How do YOU approach a pediatric patient in whom you have a moderate pretest probability for appendicitis?