Shea M J, Wilson R A, deLandsheere C M, Deanfield J E, Watson I A, Kensett M J, Jones T, Selwyn A P
J Nucl Med. 1987 Jun;28(6):989-97.
Positron emission tomography (PET) with rubidium-82 (82Rb) has been developed to measure regional myocardial perfusion and to detect transient ischemia both in the experimental laboratory and in humans. There are known and separate contaminating effects of the 82Rb signal by disturbances in wall motion, wall thinning, and the partial volume effect that occur during transient ischemia. In nine anesthetized greyhounds, PET with 82Rb (T1/2 = 78 sec) was used to determine the regional myocardial uptake of this cation during a control period that consisted of a mild stenosis of the left anterior descending coronary artery in the absence of ischemia (to limit reactive hyperemia), during 10 min of total occlusion and, finally, at 30 and 60 min of recovery with release of the occlusion but not of the stenosis. Separately, rubidium-81 (81Rb); T1/2 = 4.58 hr) was given as a peripheral intravenous injection 2 hr before the study to allow this long-lived tracer to distribute in the potassium space of the myocardium. Observations during control and ischemia revealed marked decreases in 82Rb uptake (0.84 +/- 0.12 to 0.28 +/- 0.12, p = 0.001) in affected regions and were paralleled by similar decreases in microsphere blood flow (0.88 +/- 0.08 to 0.12 +/- 0.10 ml/min/g, p = 0.003), which gradually recovered by 60 min postischemia. Lesser decreases in 81Rb activity (0.84 +/- 0.11 to 0.76 +/- 0.17, p = 0.83) were observed in the same regions during ischemia, but these were immediately reversible. Separate in vitro postmortem experiments in eight rabbits confirmed a linear relationship between plasma and myocardial activities of stable potassium and 81Rb although there was a greater concentration of 81Rb in the myocardium that in the plasma relative to potassium (y = -3.29 +/- 0.79 x, s.e.e. 1.91, r = 0.95). These studies demonstrate that if 81Rb is given intravenously to distribute into the potassium pool, tomograms of the heart may be recorded to measure the potassium-rich mass of myocardium providing information about the acute effects of wall thinning during ischemia. Rubidium-81 used in this way may be helpful in assessing the effects of wall thinning and/or scar when other tracers are being used to assess perfusion or metabolism.
利用铷 - 82（82Rb）的正电子发射断层扫描（PET）技术已被开发用于测量局部心肌灌注，并在实验室内和人体中检测短暂性心肌缺血。在短暂性心肌缺血期间，壁运动紊乱、心肌壁变薄以及部分容积效应会对82Rb信号产生已知且独立的污染影响。在9只麻醉的灵缇犬中，使用82Rb（半衰期T1/2 = 78秒）PET来确定在一个对照期内该阳离子的局部心肌摄取情况，该对照期包括在无缺血情况下左前降支冠状动脉轻度狭窄（以限制反应性充血），在完全闭塞10分钟期间，最后在闭塞解除但狭窄未解除的恢复30分钟和60分钟时。另外，在研究前2小时经外周静脉注射铷 - 81（81Rb；半衰期T1/2 = 4.58小时），以使这种长寿命示踪剂分布在心肌的钾空间中。对照期和缺血期的观察结果显示，受影响区域的82Rb摄取量显著降低（从0.84±0.12降至0.28±0.12，p = 0.001），同时微球血流也有类似程度的降低（从0.88±0.08降至0.12±0.10 ml/min/g，p = 0.003），缺血后60分钟逐渐恢复。在缺血期间，同一区域观察到81Rb活性的降低幅度较小（从0.84±0.11降至0.76±0.17，p = 0.83），但这些降低是立即可逆的。在8只兔子身上进行的单独体外死后实验证实，稳定钾和81Rb的血浆与心肌活性之间存在线性关系，尽管相对于钾而言，心肌中81Rb的浓度高于血浆（y = -3.29±0.79x，标准误1.91，r = 0.95）。这些研究表明，如果静脉注射81Rb使其分布到钾池中，可以记录心脏断层图像以测量富含钾的心肌质量，从而提供有关缺血期间心肌壁变薄急性影响的信息。当使用其他示踪剂评估灌注或代谢时，以这种方式使用的81Rb可能有助于评估心肌壁变薄和/或瘢痕的影响。
