Does Orally-Administered Radiocontrast Impair Ultrasound Image Quality in Pediatric Patients?

Introduction: It is commonly assumed that orally-administered radiocontrast material (ORC) preceding abdominal ultrasound (US) performance can obscure image quality and potentially impair diagnostic accuracy when assessing patients with abdominal pain. Due to this concern, ORC administration per protocol for computed tomography (CT) is often delayed until after US performance, potentially contributing to prolonged length of stay in the emergency department (ED) in patients with concern for abdominal pathology. The objective of this study was to evaluate whether early administration of ORC in children with abdominal pain receiving abdominal CT for possible appendicitis obscures subsequent abdominal US image quality.

Methods: We designed a prospective observational study of children <18 years of age presenting to a pediatric ED with abdominal pain who were set to receive ORC prior to obtaining an abdominal CT. These patients received a point-of-care ultrasound (POCUS) of the abdomen to assess the abdominal aorta and right lower quadrant (RLQ) structures (psoas muscle and iliac vessels) pre- and post-ORC administration. Images were compared independently by two blinded emergency US-certified physician-assessors for quality, specifically to determine whether ORC obscured the anatomical structures in question.

Results: A total of 17 subjects were enrolled, and each subject had two POCUS studies of the abdomen, one pre- and one post-ORC administration looking to visualize the anatomy of the RLQ and abdominal aorta in both studies. Statistical analysis showed no significant differences in mean values of POCUS image quality scoring by two blinded US-trained physician-assessors for either RLQ structures or abdominal aorta when performed pre- and post-administration of ORC.

Conclusion: Early ORC administration in children with abdominal pain does not adversely affect image quality of a subsequently performed abdominal US. Patients who may require abdominal CT to determine the etiology of abdominal pain can receive early administration of ORC prior to US performance to help minimize ED length of stay without impairing US diagnostic accuracy.