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(MRD)图像，表示 初始剂量和重新注入的铊剂量。确定以下内容是否足够 在运动和MRD图像识别可逆缺陷方面，我们研究了23 对慢性冠状动脉疾病患者进行运动铊SPECT检查。 除了运动和MRD图像外，我们还重新注射了另一个1MCI 在MRD图像后3-4小时显示铊。练习、MRD和3-4 然后对HR再注射图像进行归一化和定量分析。 在运动图像上的50个异常区域中，23个(46%)是 MRD不可逆。然而，这些不可逆转的缺陷中有6个(26%) (涉及23名患者中的5名)在再次注射3-4小时后逆转， 平均铊活度从57+/-5(运动)和63+/-4增加 (MRD)至74+/-7(p&lt；0.001)。MRD上27个可逆区中只有1个 再次注射3-4小时后出现不可逆。所有地区都有 仅关于3-4小时再注射图像的可逆性由 严重狭窄的冠状动脉。这些数据表明MRD成像 会高估约四分之一不可逆转的心肌纤维化 缺陷，需要3-4个小时的延迟才能准确确定 心肌缺血和存活情况。

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 (mRD) image representing redistribution of both the initial and the reinjected thallium doses. To determine the adequacy of exercise and MRD images in identifying reversible defects, we studied 23 patients with chronic coronary artery disease by exercise thallium SPECT. In addition to exercise and MRD images, we also reinjected another 1 Mci of thallium after the MRD image at 3-4 hrs. The exercise, MRD, and 3-4 hr reinjection images were then normalized and analyzed quantitatively. Of the 50 abnormal regions on the exercise images, 23 (46%) were irreversible on MRD. However, 6 (26%) of these irreversible defects (involving 5 of the 23 patients) reversed after 3-4 hr reinjection, with mean thallium activities increasing from 57+/-5 (exercise) and 63+/-4 (MRD) to 74+/-7 (p<0.001). Only 1 of 27 reversible regions on MRD 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 MRD 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.