Integrating study for clinical imaging of cerebral functions and hemodynamic parameters.

为探讨慢性脑血管病（CVD）患者脑内病理性血管改变与血流动力学改变的关系，采用PET检测脑局部血流量（rCBF）和氧代谢率（cro_2）。对104例脑动脉狭窄性疾病患者（平均年龄61.0±14.0岁）在基线和注射乙酰唑胺（ACZ）后10分钟进行O-water PET研究，以评估rCBF的区域变化。所有患者均采用稳态法进行^<15>O-gas PET研究，测量脑总血容量（CBV）、氧提取分数（OEF）和cmoro_2。通过血管舒张能力的升高和剩余来评估患者的急性灌注（II期缺血）。ACZ诱导的rCBF的平均%增加在所有CVD患者的两个半球都是显著的，尽管有一个亚组的患者在受影响的半球显示rCBF的增加显著减少。受影响皮质区域的绝对OEF与rCBF %变化无相关性，而同一区域的OEF不对称指数呈弱相关性。16例患者脑区OEF显著升高，其中7例（43.8%）ACZ试验显示血管储备显著降低。在31例受影响半球rCBF增加减少的患者中，只有7例患者（22.6%）在同一区域显示OEF增加。CVD患者对ACZ注射的rCBF反应降低并不一定与灌注不良相关。两项血流动力学参数在慢性血流动力学损害的关键阶段不相等。我们还提出了一个新的动脉脑灌注压（CPPa）参数，该参数由rCBF与动脉-毛细血管血容量（V_0）的比值定义，用于评估脑循环受损。在40例患有严重血管闭塞性疾病的患者中，大约一半的患者在受影响的大脑区域表现出血管舒张能力的降低。在这个严重脑循环受损的组中，卒中与ACZ测试中CPPa的降低显著相关。基于PET研究的这些发现，设计了用于评估脑循环受损的MRI研究，并在PET和MRI结果之间获得了良好的相关性。我们也将同样的方法应用于SPECT研究。少

To investigate relationship between pathological vascular change and hemodynamic alteration in the brain, regional cerebral blood flow (rCBF) and metabolic rate of oxygen (CMRO_2) were measured in patients with chronic cerebrovascular disease (CVD) using PET. ^<15>O-water PET studies were performed in 104 patients with major cerebral arterial stenoocclusive disease (mean age=61.0±14.0 y) at baseline and 10 min after the acetazolamide (ACZ) injection to evaluate regional changes in rCBF. All patients also underwent ^<15>O-gas PET studies using the steady-state method to measure total cerebral blood volume (CBV), oxygen extraction fraction (OEF) and CMRO_2. They were evaluated misery perfusion (stage II ischemia) defined by elevation of and residual vasodilatory capacity. The mean of % increase in rCBF induced by ACZ was significant in both hemispheres of all patients with CVD although there was a subgroup of patients who showed a significant reduction of the rCBF increase in the affecte … More d hemisphere. The absolute OEF in the affected cortical regions was not correlated with % change in rCBF, whereas asymmetry index of OEF in the same regions showed a weak correlation. Sixteen patients had cerebral regions with a significant increase in OEF, and 7 of them (43.8 %) showed a significant decrease in vascular reserve evaluated by the ACZ test. Of the 31 patients who had a reduction of rCBF increase in the affected hemisphere, only 7 patients (22.6 %) showed an OEF increase in the same region. The reduced rCBF response to the ACZ injection is not necessarily associated with misery perfusion in patients with CVD. The two hemodynamic parameters were not equivalent in the critical stage of chronic hemodynamic impairment. We also proposed a new parameter of arterial cerebral perfusion pressure (CPPa) defined by the ratio of rCBF to arterial-to-capillary blood volume (V_0) for assessment of impaired cerebral circulation. In 40 patients with severer vasoocclusiove disease, about half of them showed a reduction of vasodilatory capacity in the affected cerebral territories. In this severely impaired cerebral circulation group, strokes were significantly associated with reduction of CPPa in the ACZ test. Based on these findings from PET studies, MRI studies for evaluation of impaired cerebral circulation were designed and an excellent correlation was obtained between results from PET and MRI. We also applied the same methods to SPECT studies. Less