Sequential Changes of Cerebral Blood Flow after Acetazolamide Acetazolamide Loading in Hemodynamic Cerebral Ischemia: Relationship to Cerebral Oxygen Metabolism

本研究旨在探讨乙酰唑胺负荷后脑血流量（CBF）的动态变化与脑氧代谢（CMRO_2）的关系。受试者包括30例颈内动脉或大脑中动脉或椎基底动脉严重狭窄或闭塞的患者。用正电子发射断层扫描（PET）和[^ O] H_2O推注法分别测定静息状态和静注乙酰唑胺1g后6、16、30分钟的局部脑血流量（CBF<15>）。在进行CBF测定前，用[^ O]O_2吸入法测定局部脑氧摄取分数（OEF）<15>。根据CBF和OEF计算区域CMRO_2。其中反应良好（负荷后6min CBF增加率&gt; 20%）39个，反应反常（负荷后6min CBF下降）11个，反应不良（负荷后6min CBF增加率&lt;20%）10个。反应良好的区域OEF正常，CMRO_2正常。矛盾反应类型的区域OEF增加。反应差型地区GEF正常，CMRO_2下降。因此，序贯测定乙酰唑胺负荷后的脑血流量（CBF）可了解血流动力学缺血患者局部脑氧代谢状态，应在乙酰唑胺给药后早期测定CBF，以准确检测脑灌注的痛苦。

The aim of this study was to clarify relationship between sequential changes of cerebral blood flow (CBF) after acetazolamide loading and cerebral oxygen metabolism (CMRO_2). The subjects consisted of 30 patients with severe stenosis or occlusion of the internal carotid or middle cerebral or vertebro-basilar artery. Regional CBF was measured at the resting state and at 6, 16 and 30 minutes after the intravenous administration of 1 g acetazolamide using the [^<15>O]H_2 O bolus-injection method and positron emission tomography. Prior to CBF study, regional cerebral oxygen extraction fraction (OEF) was measured using the [^<15>O]O_2 inhalation method. Regional CMRO_2 was calculated based on CBF and OEF. Good response type (CBF increase rate more than 20% at 6 minutes after acetazolamide loading), paradoxical response type (decrease of CBF at 6 minutes after acetazolamide loading) and poor response type (CBF increase rate less than 20% at 6 minutes after acetazolamide loading) were identified in 39, 11 and 10 areas, respectively. Areas with good response type showed normal OEF and normal CMRO_2. Areas with paradoxical response type showed increased OEF. Areas with poor response type showed normal GEF and decreased CMRO_2. In view of these findings, the author concludes that sequential measurement of cerebral blood flow (CBF) after acetazolamide loading enables to know regional cerebral oxygen metabolic state in patients with hemodynamic ischemia, and CBF should be measured early after the administration of acetazolamide to accurately detect misery perfusion.