Coxson P G, Brennan K M, Huesman R H, Lim S, Budinger T F
Center for Functional Imaging, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
J Nucl Med. 1995 Feb;36(2):287-96.
Kinetic analysis of 82Rb dynamic PET data produces quantitative measures which could be used to evaluate ischemic heart disease. These measures have the potential to generate objective comparisons of different patients or the same patient at different times. To achieve this potential, it is essential to determine the variability and reproducibility of the kinetic parameters.
A total of 48 82Rb dynamic PET datasets were acquired from two pure bred beagles. Each animal underwent eight 82Rb PET studies with essentially the same protocol for three successive weeks. Data were acquired with the Donner 600-Crystal Positron Tomograph (PET600). In each week, single-slice dynamic 82Rb PET datasets were collected with the animal at rest at three different gantry positions separated by 5 mm. Additional dataset were collected after dipyridamole infusion and after administration of aminophylline to induce a return to rest. A two-compartment kinetic model with correction for myocardial vasculature and spillover from the left ventricular blood pool was used to analyze the dynamic datasets. Model parameters for uptake (k1), washout (k2) and vascular fraction (fv) were estimated in 11-14 myocardial regions of interest (ROIs) using a weighted least-squares criterion. Statistical fluctuation due to the PET acquisition process was minimized by using a relatively high 82Rb dose (about 30 mCi) to take advantage of the high count rate capacity of the PET600.
The variation in mean k1, where the mean is taken over the myocardial ROIs was 10%-20% (Dog 1) and 15%-50% (Dog 2) among the rest studies conducted on the same date. Similar variation was evident in comparing studies in the same animal for different weeks.
Spatial and temporal variation in estimates of the uptake rate (k1) of 82Rb in the resting myocardium of the anesthetized canine are small in relation to the functional increase in k1 following dipyridamole infusion.
对82Rb动态PET数据进行动力学分析可产生定量指标，这些指标可用于评估缺血性心脏病。这些指标有可能对不同患者或同一患者在不同时间进行客观比较。为实现这一潜力，确定动力学参数的变异性和可重复性至关重要。
从两只纯种比格犬获取了总共48个82Rb动态PET数据集。每只动物连续三周按照基本相同的方案进行了八次82Rb PET研究。使用唐纳600晶体正电子断层扫描仪（PET600）采集数据。每周，在动物静息状态下，在三个相隔5毫米的不同机架位置收集单层动态82Rb PET数据集。在静脉注射双嘧达莫后以及给予氨茶碱诱导恢复静息状态后收集额外的数据集。使用具有心肌血管系统校正和左心室血池溢出校正的双室动力学模型分析动态数据集。使用加权最小二乘法准则在11 - 14个心肌感兴趣区域（ROI）中估计摄取（k1）、洗脱（k2）和血管分数（fv）的模型参数。通过使用相对较高的82Rb剂量（约30 mCi）以利用PET600的高计数率能力，将PET采集过程引起的统计波动降至最低。
在同一天进行的静息研究中，心肌ROI的平均k1变化在10% - 20%（犬1）和15% - 50%（犬2）之间。在比较同一动物不同周的研究中也明显存在类似变化。
与双嘧达莫静脉注射后k1的功能增加相比，麻醉犬静息心肌中82Rb摄取率（k1）估计值的空间和时间变化较小。
