HEART IMAGING WITH SINGLE PHOTON AGENTS

缺血可恢复心肌与不可逆性心肌的鉴别 用现有的技术很难修复受伤的组织。心肌 缺血时注射~(201)Tl的灌注成像 是为了这个目的而倡导的，基于 重新分配。最近的研究发现了相当数量的 然而，缺血患者的再分布很少或没有 他们的连续血流灌注图像。另一种方法来解决 急性心肌缺血时心肌组织的改变 代谢底物偏好。虽然研究可以用正电子来完成 使用放射性标记葡萄糖类似物进行断层扫描以识别缺血 心肌，这项技术不适合在大多数医院使用， 只有传统的愤怒类型闪烁相机。另一种选择 适合与愤怒摄像头一起使用的方法，可以检测到 一种改性脂肪酸和铊在以下区域的相对浓度 缺血症。脂肪酸的分布量显著增加 缺血增加，我们实验室的初步研究表明 修饰后的脂肪酸分布的双示踪成像，3- 甲基-对-[123I]-苯基十五烷酸(具有较长的心肌 滞留时间)和铊-201可用于识别缺血 组织。正常心肌带具有相似的区域分布。 修饰的脂肪酸和铊，急性缺血区有一个 两种放射性药物的相对过量。拟议的研究将 改性脂肪酸/铊与~(14)C的行为比较 标记2-脱氧葡萄糖在实验动物中的不同程度 缺血，并将确定改良脂肪的预后价值 室壁运动异常患者的酸/铊比值 用于血运重建。

The differentiation of ischemic recoverable myocardium from irreversibly injured tissue is difficult with existing techniques. Myocardial perfusion imaging with thallium-201 with injection during ischemia has been advocated for this purpose, based on the appearance of redistribution. Recent studies identified a significant number of patients with ischemia, however, who have minimal or no redistribution on their serial perfusion images. An alternative approach to the delineation of acutely ischemic myocardial tissue utilizes changes in metabolic substrate preference. While studies can be done with positron tomography using radiolabeled glucose analogs to identify ischemic myocardium, this technique is not suitable for use in most hospitals that have only conventional Anger type scintillation cameras. An alternative approach, suitable for use with Anger cameras, can detect changes in the relative concentration of a modified fatty acid and thallium in zones of ischemia. The volume of distribution of fatty acids is markedly increased in ischemia, and preliminary studies in our laboratory suggest that dual tracer imaging of the distribution of a modified fatty acid, 3- methyl-p-[123I]-phenylpentadecanoic acid (which has a long myocardial residence time), and thallium-201, can be used to identify ischemic tissue. Normal zones of myocardium have a similar regional distribution of modified fatty acid and thallium, zones of acute ischemia have a relative excess of both radiopharmaceuticals. The proposed studies will compare the behavior of modified fatty acid/thallium to that of 14C labeled 2-deoxyglucose in experimental animals with varying degrees of ischemia, and will define the prognostic value of the modified fatty acid/thallium ratio in patients with wall motion abnormalities scheduled for revascularization.