Glowing in the dark: time of day as a determinant of radiographic imaging in the evaluation of abdominal pain in children

Abstract Background/Purpose Although ultrasound is often the preferred pediatric imaging study, many institutions lack ultrasound access at night; and computerized tomography (CT) becomes the only radiological method available for evaluation of appendicitis in children. The purpose of this study was to characterize patterns of daytime and nighttime use of ultrasound or CT for evaluation of pediatric appendicitis and to measure consequent differences in radiation exposure and cost. Methods A retrospective chart review of patients evaluated for appendicitis from October 2004 to October 2009 (N = 535) was performed to evaluate daytime and nighttime use of ultrasound and CT for pediatric patients. Results Average age was 10.2 years (range, 3-17 years). During the day, 6 times as many ultrasounds were performed as CTs (230 vs 35). At night, half as many ultrasounds were performed (50 vs 110). Average radiation dose per child during the day was significantly lower than at night (day, 0.52 mSv per patient; night, 2.75 mSv per patient). Average radiology costs were lower for daytime patients ($2491.06 day vs $4045.00 night; P Conclusions Dependence on CT at night results in higher average radiation exposure and cost. Twenty-four–hour ultrasound availability would decrease radiation exposure and cost of evaluation of children presenting with appendicitis.