Total cerebrovascular blood flow and whole brain perfusion in children sedated using propofol with or without ketamine at induction: An investigation with 2D-Cine PC and ASL

Background: Multiple sedation regimes may be used to facilitate pediatric MRI scans. These regimes might affect cerebral blood flow and hemodynamics to varying degrees, particularly in children who may be vulnerable to anesthetic side effects.

Purpose: To compare the effects of propofol monosedation solely (Pm group) vs. a combination of propofol and ketamine (KP group) on brain hemodynamics and perfusion.

Study type: Prospective double-blind randomized trial.

Field strength/sequences: 1.5T and 3T. 2D-Cine phase contrast (2D-Cine PC) and pseudocontinuous arterial spin labeling (ASL).

Population: Children aged from 3 months to 10 years referred for MRI with deep sedation were randomized into either the KP or the Pm group. Perfusion images were acquired with ASL followed by single-slice 2D-Cine PC acquired between the cervical vertebra C2 and C3.

Assessment: Average whole-brain perfusion (WBP ml.min^-1 .100 ml^-1 ) was extracted from the ASL perfusion maps and total cerebrovascular blood flow (CVF) was quantified by bilaterally summing the flow in the vertebral and the internal carotid arteries. The CVF values were converted to units of ml.min^-1 .100 g^-1 to calculate the tissue CVF_100g (ml.min^-1 .100 g^-1 ). Images were assessed by a neuroradiologist and data from n = 81 (ASL) and n = 55 (PC) cases with no apparent pathology were entered into the analysis.

Statistical tests: Multivariate analysis of covariance was performed to compare drug sedation effects on WBP, CVF, and CVF_100g .

Results: No significant difference in arterial flow was observed (P = 0.57), but the KP group showed significantly higher WBP than the Pm group, covarying for scanner and age (P = 0.003). A correlation analysis showed a significant positive correlation between mean WBP (ml.min^-1 .100 g^-1 ) and mean CVF_100g .

Data conclusion: The KP group showed higher perfusion but no significant difference in vascular flow compared with the Pm group. WBP and CVF_100g correlated significantly, but ASL appeared to have more susceptibility to perfusion differences arising from the different sedation regimes.

Level of evidence: 1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2019;50:1433-1440.