吸入二氧化碳對於功能性磁振造影、腦血管反應度、大腦血流量、大腦血流體積以及大腦血流含氧程度測量的影響

Abstract

神經活動牽涉到能源的需求與能源的供應。當神經活化時，所需的能源包括葡萄糖及氧氣會經由大腦微循環調控所增加的腦血流所供應。然而，除了神經活活之外，大腦微循環還受到神經活化之外許多因素的調控，其中包括二氧化碳。因此經由神經活化所造成的大腦微循環調控很可能會受到外加二氧化碳的影響及遮蔽。在本本論文中，我們主要探討吸入之二氧化碳對於大腦主要血管以及大腦微循環調控以及對於視覺刺激之功能性磁振造影研究的影響。 此外，我們也特別研發並提出一個混合的磁振造影波序。該磁振造影波序的優點在於可以在一次的實驗中，同步並且準確的測量大腦血流體積、大腦血流量、以及大腦血流含氧程度。實驗的結果與先前功能性磁振造影研究、正子攝影研究、以及生理學對於大腦微循環調控研究結果相符合。

The neural activity involves energy demand and energy supply. During neural activation, the energy source glucose and oxygen are supplied by increase cerebral blood flow via a regulation of the cerebral microcirculatory units. In addition to neural activation, the cerebral microcirculation is regulated by many other factors including CO2. It is very likely that the neural activation related cerebral microcirculatory regulation is overwhelmed by the external CO2 perturbation. In this thesis, we explore the effect of inhaled CO2 on cerebral vascular and microcirculatory regulations and on the visual fMRI study. Specially, we propose a hybrid pulse sequence that allows accurate measurement of cerebral blood volume, cerebral blood flow and cerebral blood oxygenation simultaneously. Experimental results are consistent with prior fMRI and PET studies and the basic understanding of cerebral microcirculatory regulation on physiology.