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.