基于NIRS-ICG的脑血流量无创测量

临床上脑血流量(cerebral blood flow, CBF)等脑血管血流动力学参数是脑血氧水平及脑血管储备功能诊断依据，现有检测手段存在技术复杂及相应试剂或设备不适用于所有诊断人群等缺点。为解决以上问题，利用近红外光谱技术(NIRS)结合吲哚青绿(indocyanine green, ICG)脉搏色素浓度法，研究了一种无创、快速、可重复测量的脑血流量床旁检测方法NIRS-ICG。该方法根据静脉注射ICG后脑组织及脑动脉血流中三种主要吸光色团氧合血红蛋白(oxygenated hemoglobin, HbO₂)、还原血红蛋白(reduced hemoglobin, HbR)及ICG的浓度变化情况，建立脑组织及脑动脉血流中ICG积累量及引入量模型，以获得脑血氧及CBF等脑血流动力学参数。为验证该方法的可行性，将NIRS-ICG应用于血碳酸正常及高碳酸血症病理模型的实验猪的脑血流情况检测。具体方法是：分别对四组实验猪用按0%，3%，6%，9%比例调制的CO₂和空气混合气体施行机械通气，静脉快速推注ICG后，利用NIRS-ICG方法测量CBF、脑动脉血氧饱和度(cerebral arterial oxygen saturation, SaO₂)及脑血管管床平均循环时间(mean transit time, MTT)。实验结果表明，NIRS-ICG测得的CBF随CO₂比率升高而升高，SaO₂随着CO₂比例的升高而降低，MTT并无显著变化，与生理变化一致。因此，该方法可为脑血氧及脑血管储备功能诊断提供可靠依据。

Noninvasive Cerebral Blood Flow Measurement Based on NIRS-ICG

Clinicians take cerebral blood flow (CBF) and ot her cerebral vascular hemodynamic parameters as diagnostic basis for cerebral bl ood oxygen and cerebrovascular reserve capability.But current detection methods have disadvantages such as technically complexity and poor universality of reag ents or equipments to all diagnostic groups.To solve the problems above,a new noninvasive,rapid and repeated technique for measurement of CBF by combination of near-infrared spectroscopy (NIRS) and indocyanine green (ICG) pulse-dye dens itometry is proposed by the name of NIRS-ICG.After ICG intravenous bolus injec tion,concentration curves of three main chromophores,which are oxygenated hemo globin,reduced hemoglobin and ICG,in both brain tissue and cerebral artery,ar e estimated.And then ICG accumulation rate and introduced quantity models are e stablished in order to obtain CBF and other cerebral vascular hemodynamic parame ters.To verify the feasibility of this method,CBF and other parameters of norm ocapnia piglet and hypercapnia piglets were detected in NIRS-ICG.3,6 and 9 p ercent of CO2 mixed with air was mechanical ventilated into four group Chinese experimental miniature pigs.NIRS-ICG was used to measure CBF,cerebral arteri al oxygen saturation (SaO2),and mean transit time (MTT) after rapidly intrave nous infusion of ICG.The test value showed that CBF increased with the increase of CO2 ratio,SaO2 decreased with the increase of CO2 ratio,and MTT had no significant change.It is proved that the measurements reflected changes in c erebral blood flow reliably.NIRS-ICG is applicable both in cerebral blood oxyg en and cerebrovascular reserve capability detection.