Quatitation of Neurotransmission using Positron Emission, Tomography : Aging Effects and Changes in Dementia Patients.

采用正电子发射断层扫描（PET）对AD/SDAT和多发梗死型血管性痴呆27例患者进行了以多巴胺系统为主的中枢神经传递分析。本机构成功标记了18f标记的氟左旋多巴（FDOPA）和11c标记的YM09151-2(YM)， aD2受体配体。顺序PET数据收集。使用美国诺克斯维尔CTI公司的PT931来记录示踪剂在纹状体的积累。开发了一种半自动的ROI绘制程序，用于识别纹状体，该纹状体交互地定义了直方图曲线和图像上定义的边界像素。以小脑放射性为输入函数，用图形图计算ROI数据的FDOPA内流率（Ki）。D2受体的浓度是通过YM到纹状体和小脑的升级率来估计的。Ki值相对稳定，没有明显的年龄相关变化。通过迷你精神量表评估Ki与痴呆严重程度之间的相关性分析显示Ki的显著降低与痴呆严重程度的进展相关。D2受体密度增加与突触前刺激减少相关的受体超敏反应一致。突触前神经元和突触后受体摄取示踪剂之间的不耦合在血管患者中最为明显，AD/SDAT患者表现出不同的趋势，这可能与这一类别的异质性起源有关。我们认为，利用正电子发射断层成像技术进行神经传递成像，可以作为一种新的诊断方式来评估体内和人体内单个神经传递系统的神经功能。

A study was initiated to analyze the central neurotransmission mainly of dopamine system of 27 subjects including AD/SDAT snd vascular dementia of multi-infarct type using positron emission tomography(PET). 18F-labeled fluoro-L-dopa(FDOPA) and 11C-labeled YM09151-2(YM), aD2 receptor ligand were successfully labeled in our institution. Sequential PET data collection. was performed using PT931, CTI inc, Knoxville, U.S.A.to recotd tracer accumulation to the striatum. A semi-automated ROI draw routine was developed to identify the striatum that interactively defined the boundary pixels defined on the histogram curves and images simultaneously. The graphical plot was employed to calculate FDOPA influx rate(Ki) for the ROI data using cerebellar radioactivity as input function. The D2 receptor concentration was estimated by uptade ratio of the YM to the striatum and to the cerebellum. The Ki values were found relatively stable and did not show significant age-related chages. The correlation analysis between Ki and severity of dementia as assessed by mini-mental scale revealed significant reduction of Ki associated with the progression of dementia severity. The D2 receptor density was increased in accordance with receptor supersensitivity related to the reduced presynaptic stimuli. This uncoupling between uptake of a tracer by presynaptic neurons and postsynaptic receptors was most noted in vascular patient, where as AD/SDAT patients showed variable trends which may relate to heterogenous origin of this category. We concludes imaging of neurotransmission with positron emission tomography can be a new diagnostic modality to assess nueronal function of individual neurotransmission system in vivo and in humam.