Associations between protocol-related operational factors, MRI duration, and propofol exposure in pediatric MRI.

BACKGROUND: Pediatric MRI frequently requires propofol anesthesia to obtain motion-free diagnostic images. Operational imaging factors may influence examination duration and anesthetic exposure, but these relationships remain incompletely characterized. OBJECTIVE: To evaluate associations between operational protocol-related operational factors, MRI duration, and propofol exposure during pediatric MRI. MATERIALS AND METHODS: This retrospective study included 2,149 pediatric MRI examinations performed under propofol anesthesia between January 2020 and May 2025. Operational imaging variables included scanner field strength (3 T vs 1.5 T), contrast-enhanced MRI, and protocol type (multi-region vs single-region). Multivariable log-linear regression models evaluated associations between operational imaging factors and MRI duration. Multivariable linear regression models assessed associations between MRI duration and total propofol exposure (mg/kg). RESULTS: Among 2,149 pediatric MRI examinations (median age 5 years [IQR 2-8]; 1,299/2,149 [60.4%] female), multi-region MRI protocols and contrast-enhanced examinations were associated with longer MRI duration, increasing examination time by 45.4% (95% CI, 40.2-50.7%; p<0.001) and 18.6% (95% CI, 14.8-22.6%; p<0.001), respectively. Imaging at 3 T was associated with a 3.9% reduction in MRI duration compared with 1.5 T (95% CI, -6.8% to -0.9%; p=0.011). Each additional 10 min of MRI duration was associated with a 0.71 mg/kg increase in propofol exposure (95% CI, 0.59-0.84; p<0.001). Adjustment for MRI duration attenuated the associations between protocol-related operational factors and propofol exposure. CONCLUSION: Protocol-related operational factors significantly influenced MRI duration, which was strongly associated with propofol exposure during pediatric MRI. MRI efficiency may represent a modifiable contributor to anesthetic burden in pediatric imaging.