Poeppel T D, Terborg C, Hautzel H, Herzog H, Witte O W, Mueller H-W, Krause B J
Klinik für Nuklearmedizin (KME) der Heinrich-Heine-Universität, Forschungszentrum Jülich, 52426 Juelich, Germany. E-mail:
Nuklearmedizin. 2007;46(3):93-100.
Transcranial Doppler sonography (TCD) is increasingly used in cerebrovascular disease for monitoring brain perfusion. It allows estimation of cerebral blood flow (CBF) by the measurement of cerebral blood flow velocity (CBFV). The CBFV as well as CBF are intimately associated with the intravascular CO2-concentration. Thus, hyper- or hypocapnia can be used to induce a defined range of blood flows. The aim of our study was the comparison of vasomotor reactivity assessed with simultaneous TCD and quantitative regional CBF-measurements (rCBF) by PET (serving as the reference method for in-vivo quantification of rCBF).
PATIENTS, METHODS: Six healthy young volunteers participated in this study. CBF was measured using 15O-butanol PET. A flow and dispersion-model was fitted to the measured time activity curves using arterial input curves. Each subject underwent five scans at five different end-tidal CO2 levels (EtCO2): 25, 32, 40, 48, and 55 mmHg. CBFV was assessed by continuous bilateral TCD of the middle cerebral artery (MCA). Volumes of interest for rCBF determination were placed in grey matter of the prefrontal cortex (PFC) as determined from individual MRIs. Comparisons between the rCBF, EtCO2 and CBFV were carried out with regression and correlation analysis and paired t-tests.
Strong positive linear correlations of rCBF and CBFV with the CO2-concentration and linear relationships between rCBF and CBFV were found in each individual. Normalised CO2-reactivities measured by TCD and PET were closely correlated.
TCD-measurements of vascular reactivity in healthy volunteers show a high correlation to those acquired with PET that serves as the reference method of quantitative rCBF-measurement. The results of the MCA insonation are a close approximation of the rCBF changes induced by variations of EtCO2.
经颅多普勒超声（TCD）在脑血管疾病中越来越多地用于监测脑灌注。它通过测量脑血流速度（CBFV）来估计脑血流量（CBF）。CBFV以及CBF与血管内二氧化碳浓度密切相关。因此，高碳酸血症或低碳酸血症可用于诱导一定范围内的血流。我们研究的目的是比较通过同步TCD评估的血管运动反应性和通过PET进行的定量局部脑血流量测量（rCBF）（作为体内rCBF定量的参考方法）。
患者、方法：6名健康年轻志愿者参与了本研究。使用15O-丁醇PET测量CBF。使用动脉输入曲线将血流和弥散模型拟合到测量的时间-活性曲线。每个受试者在五个不同的呼气末二氧化碳水平（EtCO2）下进行五次扫描：25、32、40、48和55 mmHg。通过对大脑中动脉（MCA）进行连续双侧TCD评估CBFV。根据个体MRI确定，将用于rCBF测定的感兴趣体积置于前额叶皮质（PFC）的灰质中。通过回归和相关分析以及配对t检验对rCBF、EtCO2和CBFV进行比较。
在每个个体中发现rCBF和CBFV与二氧化碳浓度呈强正线性相关，且rCBF和CBFV之间呈线性关系。通过TCD和PET测量的标准化二氧化碳反应性密切相关。
健康志愿者中TCD测量的血管反应性与作为定量rCBF测量参考方法的PET所获得的血管反应性高度相关。MCA超声检查的结果与EtCO2变化引起的rCBF变化非常接近。
