Age-related changes of normal cerebral and cardiac blood flow in children and adults aged 7 months to 61 years

Background-Cerebral and cardiac blood flow are important to the pathophysiology and development of cerebro- and cardiovascular diseases. The purpose of this study was to investigate the age dependence of normal cerebral and cardiac hemodynamics in children and adults over a broad range of ages. Methods and Results-Overall, 52 children (aged 0.6-17.2 years) and 30 adults (aged 19.2-60.7 years) without cerebro- and cardiovascular diseases were included in this study. Intracranial 4-dimensional flow and cardiac 2-dimensional phase-contrast magnetic resonance imaging were performed for all participants to measure flow parameters in the major intracranial vessels and aorta. Total cerebral blood flow (TCBF), cardiac and cerebral indexes, brain volume, and global cerebral perfusion (TCBF/brain volume) were evaluated. Flow analysis revealed that TCBF increased significantly from age 7 months to 6 years (P < 0.001) and declined thereafter (P < 0.001). Both cardiac and cerebral indices declined with age (P < 0.001). The ratio of TCBF to ascending aortic flow declined rapidly until age 18 years (P < 0.001) and remained relatively stable thereafter. Age-related changes of cerebral vascular peak velocities exhibited a trend similar to TCBF. By comparison, aortic peak velocities maintained relatively high levels in children and declined with age in adults (P < 0.001). TCBF significantly correlated with brain volume in adults (P=0.005) and in 2 pediatric subgroups, aged <7 years (P < 0.001) and 7 to 18 years (P=0.039). Conclusions-Cerebral and cardiac flow parameters are highly associated with age. The findings collectively highlight the importance of age-matched control data for the characterization of intracranial and cardiac hemodynamics.