Huang S C, Williams B A, Krivokapich J, Araujo L, Phelps M E, Schelbert H R
Department of Radiological Sciences, School of Medicine, University of California, Los Angeles 90024.
Am J Physiol. 1989 Apr;256(4 Pt 2):H1156-64. doi: 10.1152/ajpheart.1989.256.4.H1156.
Quantification of regional myocardial blood flow (MBF) with rubidium-82 (82Rb) and positron emission tomography (PET) requires the validation of a tracer kinetic model that adequately describes the kinetics of 82Rb in tissue. We performed 134 82Rb kinetic experiments in 24 isolated, arterially perfused rabbit interventricular septa at different flow rates (0.5-4.5 ml.min-1.g-1) and under the following conditions: varied concentrations of glucose (2.8-11 mM), insulin (0-5 mU/ml), and potassium (5-8 mM); varied pH (7.2-7.8); varied workload; and the addition of acetylstrophanthidin (1.0 microM). The measured 82Rb tissue time-activity curves consisted of two exponential components, with half times inversely related to MBF. The size of the slow component decreased as MBF increased (from 70% at 0.3 ml.min-1.g-1 to 30% at 2.0 ml. min-1.g-1). The kinetics were not strongly dependent on the conditions studied and were consistent with a compartmental model containing two communicating compartments. The volume of the fast exchangeable compartment and the transport rate constant from the fast to the slow compartment were found to be independent of MBF. Values of MBF were estimated with the compartmental model from 82Rb kinetics, and they correlated well with the directly measured MBF (r = 0.91; slope = 1.03).
利用铷 - 82（82Rb）和正电子发射断层扫描（PET）对局部心肌血流量（MBF）进行定量分析，需要验证一个能充分描述82Rb在组织中动力学的示踪剂动力学模型。我们在24个离体的、动脉灌注的兔室间隔上进行了134次82Rb动力学实验，实验条件如下：不同的流速（0.5 - 4.5 ml·min-1·g-1），以及不同浓度的葡萄糖（2.8 - 11 mM）、胰岛素（0 - 5 mU/ml）和钾（5 - 8 mM）；不同的pH值（7.2 - 7.8）；不同的工作负荷；以及添加乙酰毒毛旋花子苷（1.0 microM）。所测量的82Rb组织时间 - 活性曲线由两个指数成分组成，半衰期与MBF呈反比关系。慢成分的大小随着MBF的增加而减小（从0.3 ml·min-1·g-1时的70%降至2.0 ml·min-1·g-1时的30%）。动力学并不强烈依赖于所研究的条件，并且与一个包含两个相互连通隔室的隔室模型一致。发现快速可交换隔室的体积以及从快速隔室到慢速隔室的转运速率常数与MBF无关。利用隔室模型从82Rb动力学估算出MBF值，其与直接测量的MBF相关性良好（r = 0.91；斜率 = 1.03）。
