Regional differences in cerebral vascular response to Paco2 changes in humans measured by positron emission tomography
Regional differences in cerebral vascular response to Paco2 changes in humans measured by positron emission tomography
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DOI：
10.1097/00004647-200008000-00011
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发表时间：
2000-08-01
影响因子：
6.3
通讯作者：
Kanno, I
中科院分区：
文献类型：
--
作者：
Ito, H;Yokoyama, I;Kanno, I
高碳酸血症和低碳酸血症分别引起脑血管舒张和血管收缩。然而，区域差异的血管反应的变化在人的大脑中的二氧化碳分压并不明显。在本研究中，对这些区域差异进行了评估。在每一个Il健康受试者中，使用O-15-水和正电子发射断层扫描在休息时和在高碳酸血症和低碳酸血症期间测量脑血流量（CBF）。将所有CBF图像针对CBF进行全局标准化，并转换为标准脑解剖结构，在逐个像素的基础上计算静息和高碳酸血症或低碳酸血症条件之间的t值。在围栏、小脑、丘脑和壳核中，在高碳酸血症期间观察到显著的相对高灌注，表明血管舒张能力很大。在围栏和壳核中，还观察到低碳酸血症期间显著的相对灌注不足，即血管收缩能力大，表明血管反应性显著。在颞叶、颞枕叶和枕叶皮质中，观察到高碳酸血症期间显著的相对低灌注和低碳酸血症期间显著的相对低灌注，表明：静息时的脑血管张力可能倾向于血管舒张。在通过高碳酸血症评估脑灌注储备和校正受试者静息PaCO 2变化的CBF测量值时，应考虑脑血管反应的这种区域异质性。
Hypercapnia and hypocapnia produce cerebral vasodilation and vasoconstriction, respectively. However, regional differences in the vascular response to changes in PaCO2 in the human brain are not pronounced. In the current study, these regional differences were evaluated. In each of the Il healthy subjects, cerebral blood flow (CBF) was measured using O-15-water and positron emission tomography at rest and during hypercapnia and hypocapnia. All CBF images were globally normalized for CBF and transformed into the standard brain anatomy, t values between rest and hypercapnia or hypocapnia conditions were calculated on a pixel-by-pixel basis. In the pens, cerebellum, thalamus, and putamen, significant relative hyperperfusion during hypercapnia was observed, indicating a large capacity for vasodilatation. In the pens and putamen, a significant relative hypoperfusion during hypocapnia, that is, a large capacity for vasoconstriction, was also observed, indicating marked vascular responsiveness. In the temporal, temporo-occipital, and occipital cortices, significant relative hypoperfusion during hypercapnia and significant relative hypoperfusion during hypocapnia were observed, indicating: that cerebral vascular tone at rest might incline toward vasodilatation. Such regional heterogeneity of the cerebral vascular response should be considered in the assessment of cerebral perfusion reserve by hypercapnia and in the correction of CBF measurements for variations in subjects' resting PaCO2.