Properties of ultrasound-rapid MRI clinical diagnostic pathway in suspected pediatric appendicitis

Am J Emerg Med. 2023 Sep:71:217-224. doi: 10.1016/j.ajem.2023.06.026. Epub 2023 Jun 16.


Objective: to determine diagnostic accuracy of an US-MRI clinical diagnostic pathway to detect appendicitis in the emergency department (ED).

Study design: prospective cohort study of 624 previously healthy children 4-17 years old undergoing US for suspected appendicitis and clinical re-assessment. Children with non-diagnostic USs and persistent appendicitis concern/conclusive US-reassessment discrepancies underwent ultra-rapid MRI (US-MRI pathway), interpreted as positive, negative or non-diagnostic. Cases with missed appendicitis, negative appendectomies, and CT utilization were considered clinically diagnostically inaccurate. Primary outcome was the proportion of accurate diagnoses of appendicitis/lack thereof by the pathway.

Results: 150/624 (24%) children had appendicitis;255 USs (40.9%) were non-diagnostic. Of 139 US-MRI pathway children (after 117 non-diagnostic and 22 conclusive USs), 137 [98.6%; 95% CI 0.96-1.00] had clinically accurate outcomes (1 CT, 1 negative appendectomy): sensitivity 18/18 [100%], specificity 119/121 [98.3%], positive predictive value 18/20 [90.5%], negative predictive value 119/119 [100%]. MRI imaging accuracy was 134/139 (96.4%); 3 MRIs were non-diagnostic (no appendicitis). In the overall algorithm, 616/624 [98.7% (0.97-0.99)] patients had accurate outcomes: 147/150 (98.0%) appendicitis cases had confirmatory surgeries (3 CTs) and 469/474 (98.9%) appendicitis-negative children had no surgery/CT.

Conclusion: this study demonstrated high clinical accuracy of the US-rapid-MRI pathway in suspected pediatric appendicitis after non-diagnostic US.

Keywords: Appendicitis; Children; MRI; Ultrasound.

MeSH terms

  • Adolescent
  • Appendectomy
  • Appendicitis* / diagnostic imaging
  • Appendicitis* / surgery
  • Child
  • Child, Preschool
  • Humans
  • Magnetic Resonance Imaging / methods
  • Predictive Value of Tests
  • Prospective Studies
  • Retrospective Studies
  • Sensitivity and Specificity
  • Ultrasonography