HEART IMAGING WITH SINGLE PHOTON AGENTS

缺血可恢复心肌与不可逆心肌的鉴别 现有技术难以处理受伤的组织。 心肌 在缺血期间注射铊-201进行灌注成像， 为此目的，根据外观， 再分配 最近的研究发现， 然而，缺血患者， 他们的连续灌注图像。 的替代方法 急性缺血心肌组织的描绘利用了 代谢底物偏好 虽然研究可以用正电子 使用放射性标记的葡萄糖类似物的断层摄影术来识别缺血性 心肌，这种技术不适合在大多数医院使用， 只有传统的Anger型闪烁照相机。 一个替代 方法，适用于愤怒相机，可以检测到的变化， 改性脂肪酸和铊的相对浓度， 缺血 脂肪酸的分布容积显著增加， 缺血增加，我们实验室的初步研究表明， 双示踪剂成像的分布的改性脂肪酸，3- 甲基-对-[123 I]-苯基十五烷酸（其具有长的心肌 停留时间）和铊-201，可用于识别缺血性 组织. 正常心肌区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 将改性脂肪酸/铊的行为与14 C的行为进行比较 标记的2-脱氧葡萄糖在实验动物中具有不同程度的 缺血，并将定义修饰的脂肪酸的预后价值， 计划的室壁运动异常患者的酸/铊比值 进行血管重建

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.