Effect of focused protocol on reducing radiation dose for children who require computed tomography for suspected appendicitis

Background: Despite efforts to incorporate ultrasound into the evaluation of children for appendicitis, computed tomography (CT) is often used to aid in its diagnosis. CT scans, however, expose children to a considerable amount of radiation. In 2017, our institution began using a height-based Focused CT protocol for children with suspected appendicitis in need of CT. Objective: To compare the radiation dose received by children with suspected appendicitis who underwent a Standard Cr of the abdomen and pelvis (CTAP) with that of a Focused CT. Methods: We conducted a retrospective study of children <18 years who underwent a CT scan for suspected appendicitis (2014-2020). We included all patients whose indication for CT was "appendicitis" or "right lower quadrant pain" and excluded those whose Cr scan record lacked a radiation dose report. The effective radiation dose delivered was calculated using the dose-length product from the dose report. We compared the effective dose of those who received a Standard CTAP to those who received a Focused Cr. To account for differences in radiation dose over time and by CT scanner, analyses were adjusted for CT dose index volume (CTDIvol) and size-specific dose estimate (SSDE) using quantile regression. Results: A total of 474 patients who underwent CT were included. Prior to CT, 362(76%) had received an ultrasound. In total, 309(65%) patients underwent a Standard CTAP and 165(35%) underwent a Focused CT. The appendix was identified in 259(84%) Standard CTAPs compared to 151(92%) Focused CTs (p = 0.02). Compared to the Standard CTAP, children who received a Focused CT were exposed to a significantly lower effective dose (relative difference: CTDI-adjusted -13%[95%CI:-21,-5]; SSDE-adjusted -14%[95% CI:-24,-31). Conclusions: Our height-based Focused Cr protocol reduces radiation for children undergoing CT evaluation for suspected appendicitis without sacrificing diagnostic accuracy. Further study is needed to validate these findings at other institutions. (C) 2021 Elsevier Inc. All rights reserved.