Henriksen Otto M, Jensen Lars T, Krabbe Katja, Larsson Henrik B W, Rostrup Egill
Functional Imaging Unit, Section of Clinical Physiology and Nuclear Medicine, Department of Diagnostics, Glostrup Hospital, Copenhagen University Hospital, Glostrup, Denmark; Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Clin Physiol Funct Imaging. 2014 Nov;34(6):471-7. doi: 10.1111/cpf.12119. Epub 2013 Dec 8.
Although both impaired cardiac function and reduced cerebral blood flow are associated with ageing, current knowledge of the influence of cardiac function on resting cerebral blood flow (CBF) is limited. The aim of this study was to investigate the potential effects of cardiac function on CBF. CBF and cardiac output were measured in 31 healthy subjects 50-75 years old using magnetic resonance imaging techniques. Mean values of CBF, cardiac output and cardiac index were 43.6 ml per 100 g min(-1), 5.5 l min(-1) and 2.7 l min(-1) m(-2), respectively, in males, and 53.4 ml per 100 g min(-1), 4.3 l min(-1) and 2.4 l min(-1) m(-2), respectively, in females. No effects of cardiac output or cardiac index on CBF or structural signs of brain ageing were observed. However, fractional brain flow defined as the ratio of total brain flow to cardiac output was inversely correlated with cardiac index (r(2) = 0.22, P = 0.008) and furthermore lower in males than in females (8.6% versus 12.5%, P = 0.003). Fractional brain flow was also inversely correlated with cerebral white matter lesion grade, although this effect was not significant when adjusted for age. Frequency analysis of heart rate variability showed a gender-related inverse association of increased low-to-high-frequency power ratio with CBF and fractional brain flow. The findings do not support a direct effect of cardiac function on CBF, but demonstrates gender-related differences in cardiac output distribution. We propose fractional brain flow as a novel index that may be a useful marker of adequate brain perfusion in the context of ageing as well as cardiovascular disease.
虽然心脏功能受损和脑血流量减少都与衰老有关，但目前关于心脏功能对静息脑血流量（CBF）影响的认识有限。本研究的目的是调查心脏功能对CBF的潜在影响。使用磁共振成像技术对31名50 - 75岁的健康受试者测量了CBF和心输出量。男性的CBF、心输出量和心脏指数的平均值分别为每100克每分钟43.6毫升、每分钟5.5升和每分钟每平方米2.7升，女性分别为每100克每分钟53.4毫升、每分钟4.3升和每分钟每平方米2.4升。未观察到心输出量或心脏指数对CBF或脑老化结构迹象的影响。然而，定义为全脑血流量与心输出量之比的脑血流量分数与心脏指数呈负相关（r² = 0.22，P = 0.008），而且男性低于女性（8.6%对12.5%，P = 0.003）。脑血流量分数也与脑白质病变分级呈负相关，尽管在调整年龄后这种影响不显著。心率变异性的频率分析显示，低频与高频功率比增加与CBF和脑血流量分数存在性别相关的负相关。研究结果不支持心脏功能对CBF有直接影响，但表明心输出量分布存在性别差异。我们提出脑血流量分数作为一个新的指标，在衰老以及心血管疾病背景下可能是脑灌注充足的有用标志物。
