Ultrasound (US) has evolved as the principal imaging modality in the evaluation of pediatric appendicitis due to inherent advantages but may vary in performance based on setting. Rapid focused Magnetic Resonance Imaging (rapid MRI) is a feasible alternative, but emergency department (ED) length of stay (LOS) may be impacted. We wished to determine the performance and LOS of US and rapid MRI in a pediatric ED within a general hospital in the evaluation of appendicitis. We conducted a retrospective diagnostic accuracy study of patients < 18 years of age with abdominal pain receiving imaging for evaluation of appendicitis (US or rapid MRI). We report descriptive statistics on demographics and clinical characteristics of the study population. We conducted a sensitivity analysis by the different imaging type and combinations performed. Sensitivity and specificity for US and rapid MRI were 65.3% (95% CI: 57.5%–72.5%); 97.0% (95% CI: 94.5%–98.5%) and 98.3% (95% CI: 90.6%–100.0%); 96.1%, (95% CI: 91.1%–98.7%), respectively. US alone was associated with the shortest median ED LOS (5.3 hours, IQR 3.9–7.8), followed by rapid MRI alone (7.9 hours, IQR 5.4–8.6). US with subsequent rapid MRI was associated with the longest ED LOS (10.6 hours, IQR 7.6–13.3). US was nondiagnostic for a substantial number of studies performed resulting in suboptimal sensitivity for the diagnosis of appendicitis. Rapid MRI had better sensitivity but a greater LOS. Future work should focus on determining potential barriers that exist and incorporating strategies to enhance US performance and/or decrease rapid MRI LOS.
Johnson et al. (2026) studied this question.