IDENTIFICATION OF VIABLE MYOCARDIUM IN LEFT VENTRICULAR DYSFUNCTION

铊再注入方案的缺点是需要3套 运动后，3-4小时重新分配和重新注射图像。一个 有吸引力的替代方案是立即重新注入1mci的铊 运动图像和成像3-4小时后，产生修改的 重分布图像，表示初始和 重新注入的铊剂量。为了确定锻炼和锻炼的充分性 改进的再分布图像在识别可逆缺陷中的应用 研究了32名慢性阻塞性肺疾病患者(年龄40至76岁；23名男性和9名女性) 冠状动脉疾病的运动铊断层扫描。除了……之外 锻炼和修改后的重新分配图像，我们还重新注射了另一个 改进后的重分布图像在3~4h后1mCi的铊。 锻炼、改良的重分布和3-4小时的再注射图像 然后进行归一化和量化分析。在81个异常区域中 在运动图像上，30(37%)在修改后是不可逆的 重新分发图像。然而，在这些不可逆转的缺陷中，有7个(23%) 重新注射3-4小时后逆转，平均铊活性 从54+5(锻炼)和57+4(修改后的重新分配)增加到 69+7(再注入，p&lt；0.001)。51个可逆区中只有4个处于修饰状态 再注射3-4小时后再分布不可逆。全 仅在3-4小时再注射图像上具有可逆性的区域为 由严重狭窄的冠状动脉供应。这些数据表明 改良的再分布成像会高估心肌 大约四分之一不可逆转的缺损处出现纤维化，延迟3-4小时 对于准确确定心肌缺血和 生存能力。

Thallium reinjection protocols have the disadvantage of requiring 3 sets of images, after exercise, 3-4 hr redistribution, and reinjection. An attractive alternative is to reinject 1 mCi of thallium immediately after the exercise images and imaging 3-4 hrs later, yielding a modified redistribution image representing redistribution of both the initial and the reinjected thallium doses. To determine the adequacy of exercise and modified redistribution images in identifying reversible defects, we studied 32 patients (ages 40 to 76; 23 men and 9 women) with chronic coronary artery disease by exercise thallium tomography. In addition to exercise and modified redistribution images, we also reinjected another 1 mCi of thallium after the modified redistribution image at 3-4 hrs. The exercise, modified redistribution, and 3-4 hr reinjection images were then normalized and analyzed quantitatively. Of the 81 abnormal regions on the exercise images, 30 (37%) were irreversible on modified redistribution images. However, 7 (23%) of these irreversible defects reversed after 3-4 hr reinjection, with mean thallium activities increasing from 54+5 (exercise) and 57+4 (modified redistribution) to 69+7 (reinjection, p<0.001). Only 4 of 51 reversible regions on modified redistribution appeared irreversible after 3-4 hr reinjection. All regions with reversibility only on 3-4 hr reinjection images were supplied by critically stenosed coronary arteries. These data suggest that modified redistribution imaging will overestimate myocardial fibrosis in roughly 1/4 of irreversible defects and that a 3-4 hr delay is necessary for accurate determination of myocardial ischemia and viability.