[The impact of increased cardiac output induced by dobutamine on cerebral blood flow based on MRI 3D-pcASL...

Objective: To investigate the effect of increased cardiac output induced by dobutamine on cerebral blood flow (CBF) in healthy volunteers using magnetic resonance 3D-pseudo-continuous arterial spin labeling technology. Methods: A prospective study was conducted on 48 healthy volunteers recruited by handy sampling from June 2021 to January 2022. Physiological parameters before (at rest state) and after (under stress state) dobutamine-induced increase in cardiac output were analyzed. Quantitative CBF maps were generated by using arterial spin labeling difference imaging and proton density weighted reference image processing, and CBF changes under the rest and stress states were compared. Multivariable logistic regression model was used to analyze factors associated with reduced CBF. Results: A total of 48 subjects were included, with an age [M (Q₁, Q₃)] of 25.0 (24.0, 28.0) years, including 43 men and 5 women. Compared with the rest state, the CBF in the anterior cerebral artery [(36.2±6.9) vs (34.5±6.5) ml·(100 g)^-1·min^-1, P=0.006] and the middle cerebral artery perfusion area [(35.8±6.5) vs (34.1±6.4) ml·(100 g)^-1·min^-1, P=0.006] decreased under the stress state, however there was no statistically significant change in CBF in the posterior cerebral artery and the vertebral-basilar artery perfusion area (all P>0.05). Logistic regression analysis showed that the decrease in CBF in the anterior cerebral artery and middle cerebral artery supply regions during the stress state were correlated with an increase in diastolic blood pressure [OR (95%CI): 0.887 (0.796-0.989) and 0.895 (0.805-0.994), both P<0.05]. Conclusions: Dobutamine-induced increase in cardiac output leads to a decrease in CBF in anterior cerebral circulation but has no effect on posterior circulation. The increase in diastolic blood pressure is associated with decreased CBF under the stress state. Changes in CBF should be considered in the context of increased cardiac output.