THALLIUM KINETICS IN NORMAL AND ISCHEMIC MYOCARDIUM

心肌Tl相对活度随时间变化的测定 在序贯成像研究中越来越多地被用于临床环境 用于检测或评估冠状动脉疾病。世俗的 心肌组织中铊浓度的行为必然与 心肌摄取平衡与内源性洗脱的关系 正常和缺血状态的这些动力学参数还有待确定。 这项提案的总体目标是为 理解和解释Tl摄取的各种模式和 重新分配，并将重要的传输系数作为 血流灌注状态和MVO2改变的功能。使用动力学的可能性 铊的交换率作为一种量化功能程度的手段 还将探讨冠状动脉狭窄的严重程度。实验将是 在犬模型中按顺序进行，1)测定浸出物的分数 作为心肌血流量函数的铊的值，2)测量 不同生理条件下Tl-201心肌本征洗脱率的研究 改变心肌血流量、MVO2或两者的情况，3)至 确定这些改变对心肌摄取和 静脉注射放射性核素后的再分布，以及4) 直接介入治疗后患者固有心肌铊洗脱率的测定 并将这些测量与冠状动脉内注射的程度联系起来。 冠状动脉狭窄和节段性室壁运动异常。它是 预计从这些犬类和患者研究中获得的信息 将为理解和正确利用 放射性核素心肌显像评价急性心肌梗死患者的心肌铊动力学 疑似或公认的冠状动脉疾病。

The determination of relative myocardial thallium activity as a function of time in sequential imaging studies is being increasingly used in the clinical setting for the detection or evaluation of coronary artery disease. The temporal behavior of myocardial thallium concentration is necessarily related to the balance of myocardial uptake and intrinsic washout, yet the relationship of these kinetic parameters to normal and ischemic states has yet to be determined. The overall objective of this proposal is to provide a logical framework for understanding and interpreting various patterns of thallium uptake and redistribution, and to measure the important transport coefficients as a function of altered perfusion states and MVO2. The possibility of using kinetic exchange rates of thallium as a means of quantitating the functional degree of severity of coronary artery stenoses will also be explored. Experiments will be carried out in canine models in order, 1) to determine extraction fraction values for thallium as a function of myocardial blood flow, 2) To measure intrinsic myocardial washout rates of thallium-201 under various physiologic conditions which alter either myocardial blood flow, MVO2 or both, 3) To determine the effects of these alterations on myocardial uptake and redistribution following intravenous injection of the radionuclide, and 4) to measure intrinsic myocardial thallium washout rates in patients following direct intracoronary injection and to relate these measurements to the degree of coronary artery narrowing and regional wall motion abnormalities. It is expected that the information obtained from these canine and patient studies will provide a fundamental basis for the understanding and proper utilization of myocardial thallium kinetics for scintigraphic assessment of patients with suspected or recognized coronary artery disease.