Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception: A Multicenter, Noninferiority Study of Paired Diagnostic Tests

Abstract

Study objective: To determine the diagnostic accuracy of point-of-care ultrasound (POCUS) performed by experienced clinician sonologists compared to radiology-performed ultrasound (RADUS) for detection of clinically important intussusception, defined as intussusception requiring radiographic or surgical reduction.

Methods: We conducted a multicenter, noninferiority, observational study among a convenience sample of children aged 3 months to 6 years treated in tertiary care emergency departments across North and Central America, Europe, and Australia. The primary outcome was diagnostic accuracy of POCUS and RADUS with respect to clinically important intussusception. Sample size was determined using a 4-percentage-point noninferiority margin for the absolute difference in accuracy. Secondary outcomes included agreement between POCUS and RADUS for identification of secondary sonographic findings.

Results: The analysis included 256 children across 17 sites (35 sonologists). Of the 256 children, 58 (22.7%) had clinically important intussusception. POCUS identified 60 (23.4%) children with clinically important intussusception. The diagnostic accuracy of POCUS was 97.7% (95% confidence interval [CI] 94.9% to 99.0%), compared to 99.3% (95% CI 96.8% to 99.9%) for RADUS. The absolute difference between the accuracy of RADUS and that of POCUS was 1.5 percentage points (95% CI −0.6 to 3.6). Sensitivity for POCUS was 96.6% (95% CI 87.2% to 99.1%), and specificity was 98.0% (95% CI 94.7% to 99.2%). Agreement was high between POCUS and RADUS for identification of trapped free fluid (83.3%, n=40/48) and decreased color Doppler signal (95.7%, n=22/23).

Conclusion: Our findings suggest that the diagnostic accuracy of POCUS performed by experienced clinician sonologists may be noninferior to that of RADUS for detection of clinically important intussusception. Given the limitations of convenience sampling and spectrum bias, a larger randomized controlled trial is warranted.