DETERMINATION OF F-18 FLUORO-2-DEOXY-D-GLUCOSE RATE CONSTANTS IN THE ANESTHETIZED BABOON BRAIN WITH DYNAMIC POSITRON TOMOGRAPHY
DETERMINATION OF F-18 FLUORO-2-DEOXY-D-GLUCOSE RATE CONSTANTS IN THE ANESTHETIZED BABOON BRAIN WITH DYNAMIC POSITRON TOMOGRAPHY
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DOI：
10.1016/0165-0270(93)90033-n
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发表时间：
1993-12-01
影响因子：
3
通讯作者：
BARON, JC
中科院分区：
文献类型：
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作者：
MIYAZAWA, H;OSMONT, A;BARON, JC
我们已经确定了f -18氟脱氧葡萄糖（FDG）在未受损狒狒大脑中的速率常数（k(i)*），用于葡萄糖利用的正电子发射断层扫描（PET）测量。与之前的报告相比，我们使用了一种放射性合成方法，保证了FDG的生产基本上不受氟脱氧甘糖的污染，并通过(1)直接测量药物到达股动脉血浆和大脑之间的时移，(2)快速初始PET帧，(3)延长数据采集时间（长达180分钟）改进了kp的测定。在苯环利定或依托咪酯麻醉下研究了年轻的成年狒狒。颞叶灰质FDG时间-活性曲线在约80 min后呈现持续下降，表明确实存在产品损失。采用五参数(k -1* - k（4)*和血管体积（V-0））和四参数（k -1* - k(3)*,V-0）模型进行三室建模，以增加拟合间隔（20-120 min）。对于后者，两者计算出的FDG净间隙(（K* = K-1*）。K (3)*/(K (2)* + K(3)*))，拟合动力学常数随拟合区间的变化而变化，表现为持续的不稳定性。对于前者，常数k(4)*（可能代表去磷酸化）在较短的拟合时间内被高估且不稳定（可能是由于样品组织中的异质脑区），但在拟合时间大于或等于80分钟时稳定在类似于0.01 min(-1)；k -1* - k(3)*和k *在此之后也趋于稳定。两种麻醉方案的结果相同。因此，在麻醉狒狒中，FDG k(i)*值可以根据适当的PET采集范例和包含k(4)*和大于或等于80分钟时间-活动数据的模型可靠地确定。
We have determined the rate constants (k(i)*) of F-18-fluorodeoxyglucose (FDG) in the unlesioned baboon brain, for use in positron emission tomography (PET) measurements of glucose utilization. In contrast to earlier reports, we used a radiosynthesis which garantees production of FDG essentially uncontaminated by fluorodeoxymannose, and an improved determination of kp by (1) direct measurement of the time-shift between bolus arrival in femoral arterial plasma and brain, (2) rapid initial PET frames, and (3) extended data acquisition (up to 180 min). Young adult baboons were studied under anesthesia with either phencyclidine or etomidate. The FDG time-activity curves obtained from temporal grey matter showed a consistent decline after about 80 min, indicating true product loss. Three-compartment modelling was performed for increasing fitting intervals (20-120 min) with both a 5-parameter (K-1* - k(4)*, and vascular volume (V-0)) and a 4-parameter (K-1* - k(3)*,V-0) model. With the latter, both the calculated FDG net clearance ((K* = K-1*.k(3)*/(k(2)* + k(3)*)) and the fitted kinetic constants were dependent on fitting interval, i.e., they showed sustained unstability. With the former, the constant k(4)*, which presumably represents dephosphorylation, was overestimated and unstable for short fitting times (presumably due to heterogeneous brain compartments in the sample tissue), but stabilized at similar to 0.01 min(-1) for fitting times greater than or equal to 80 min; K-1* - k(3)* and K* were also stable after this time. These findings were identical for both anesthetic regimen. Thus, in the anesthetized baboon, the FDG k(i)* values can be reliably determined based on an adequate PET acquisition paradigm and with a model that incorporates k(4)* and greater than or equal to 80 min time-activity data.