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

UMMS Affiliation

Department of Pediatrics; Department of Surgery; Department of Radiology; Department of Emergency Medicine

Publication Date


Document Type



Abdominal Pain; Acute Disease; Adolescent; Appendicitis; Child; Child, Preschool; Circadian Rhythm; Female; Health Care Costs; Humans; Male; Radiation Dosage; Sex Distribution; Time Factors; Tomography, X-Ray Computed; data


Emergency Medicine | Pediatrics


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 < .05).

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.

DOI of Published Version



J Pediatr Surg. 2011 Jan;46(1):188-91. Link to article on publisher's site

Journal/Book/Conference Title

Journal of pediatric surgery

Related Resources

Link to Article in PubMed

PubMed ID