Predicting anesthesia exposure during MRI scans

July 15, 2020

An investigation examines whether the length of a magnetic resonance imaging (MRI) scan can predict anesthesia exposure.

Due to the long-term neurologic outcomes associated with exposure to anesthesia, there has been a push to minimize the amount of scan time under anesthesia for pediatric magnetic resonance imaging (MRI) scans. An investigation in the American Journal of Roentgenology looks at how amount of time could predict anesthesia dose.1

Investigators used electronic health records to retrospectively find MRI exams that had been performed under propofol anesthesia from 2016 to 2019 in patients aged 0 to 18 years. Examinations of brain, brain and spine, brain and abdomen, and brain, head, and neck were included.

The study included 501 exams performed on 426 patients. Overall, single body part exams were shorter, an average of 52.7 ± 18.4 min, and involved a smaller dose of propofol, an average of 17.7 ± 5.7 mg/kg, when compared to an MRI exam of multiple body parts which had an average time of 89.3 ± 26.4 min and required an average dose of 26.1 ± 7.7 mg/kg. Longer MRI scan times and higher exposure to propofol in single body part exams were linked with intravenous (IV) contrast administration, 1.5T magnet, and oncologic diagnosis. Following a multivariable analysis, IV contrast administration and multiple part examination, an MRI scan time predicted more exposure to propofol. A 3T magnet predicted lower exposure.

Researchers concluded that their findings provide a baseline to help future efforts to cut pediatric MRI anesthesia doses as well as scan times.


1. Machado-Rivas F, Leitman E, Jaimes C et al. Predictors of anesthetic exposure in pediatric MRI. American Journal of Roentgenology. July 8, 2020. Epub ahead of print. doi:10.2214/ajr.20.23601