Sandler M P, Videlefsky S, Delbeke D, Patton J A, Meyerowitz C, Martin W H, Ohana I
Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2675, USA.
J Am Coll Cardiol. 1995 Oct;26(4):870-8. doi: 10.1016/0735-1097(95)00295-6.
This study sought to develop a dual-isotope single-acquisition single-photon emission computed tomographic (SPECT) protocol using a multihead SPECT camera equipped with an ultra-high energy collimator to evaluate rest metabolism/stress perfusion simultaneously with fluorine-18 (F-18) deoxyglucose/technetium-99m (Tc-99m) 2-hexakis-2-methoxy-2-methylpropyl isonitrile (MIBI).
The most accurate and logistic method of identifying injured but viable myocardium remains a diagnostic challenge.
Sixty-five patients were given 25 to 50 g of glucose and, after approximately 60 min, an injection of 370 MBq (10 mCi) of F-18 fluorodeoxyglucose. After a 35-min distribution phase, patients underwent exercise or pharmacologic stress followed by administration of 925 MBq (25 mCi) of Tc-99m MIBI. Five patients underwent F-18 fluorodeoxyglucose position emission tomography before dual-isotope SPECT:
With a window of 20% for both photopeaks and a technetium-99m/fluorine-18 concentration of 3.2:1, the "spillover" from fluorine-18 into the technetium-99m window is < 6% of the total counts in the window in patients with a normal distribution of both radiopharmaceuticals. Phantom images clearly demonstrated cardiac defects measuring 2 x 1 and 2 x 0.5 cm. There was no significant difference in the images of the five patients who underwent both positron emission tomography and SPECT: Fifty-seven patients (mean [+/- SD] age 55 +/- 15 years, range 25 to 83; 38 men, 19 women) had satisfactory images and were included in the study. Twenty-one patients had normal study results; 15 had mismatched defects; 14 had matched defects; and 7 had both matched and mismatched defects. Twenty-three patients (mean age 54 +/- 6 years, range 30 to 83; 14 men, 9 women) underwent coronary angiography within 3 months of dual-isotope SPECT: There were seven normal studies, eight with mismatched defects, one with a matched defect and seven with matched and mismatched defects. When stenosis > 70% was used as the criterion for a diagnosis of coronary artery disease, dual-isotope SPECT had a sensitivity of 100%, specificity of 88%, positive predictive value of 93%, negative predictive value of 100% and an accuracy of 96%.
Dual-isotope SPECT may provide an alternative, accurate, cost-effective method to nitrogen-13 ammonia/F-18 fluorodeoxyglucose positron emission tomography or thallium-201 reinjection for identifying injured or dysfunctional but viable myocardium.
本研究旨在开发一种双同位素单采集单光子发射计算机断层扫描（SPECT）方案，该方案使用配备超高能准直器的多头SPECT相机，以同时利用氟 - 18（F - 18）脱氧葡萄糖/锝 - 99m（Tc - 99m）2,2'-甲氧基-2-甲基丙基异腈（MIBI）评估静息代谢/负荷灌注情况。
识别受损但存活的心肌最准确且符合逻辑的方法仍然是一项诊断挑战。
65例患者先给予25至50克葡萄糖，约60分钟后注射370兆贝可（10毫居里）的F - 18氟脱氧葡萄糖。在35分钟的分布期后，患者进行运动或药物负荷试验，随后给予925兆贝可（25毫居里）的Tc - 99m MIBI。5例患者在进行双同位素SPECT之前接受了F - 18氟脱氧葡萄糖正电子发射断层扫描。
对于两个光电峰均采用20%的窗宽，且锝 - 99m/氟 - 18浓度为3.2:1时，在两种放射性药物分布正常的患者中，氟 - 18向锝 - 99m窗的“溢出”小于窗内总计数的6%。体模图像清晰显示出尺寸为2×1厘米和2×0.5厘米的心脏缺损。接受正电子发射断层扫描和SPECT的5例患者的图像无显著差异。57例患者（平均年龄[±标准差]55±15岁，范围25至83岁；38例男性，19例女性）图像满意并纳入研究。21例患者检查结果正常；15例有不匹配缺损；14例有匹配缺损；7例既有匹配缺损又有不匹配缺损。23例患者（平均年龄54±6岁，范围30至83岁；14例男性，9例女性）在双同位素SPECT后3个月内接受了冠状动脉造影：7例检查正常，8例有不匹配缺损，1例有匹配缺损，7例既有匹配缺损又有不匹配缺损。以狭窄>70%作为冠状动脉疾病的诊断标准时，双同位素SPECT的敏感性为100%，特异性为88%，阳性预测值为93%，阴性预测值为100%且准确性为96%。
双同位素SPECT可能为氮 - 13氨/F - 18氟脱氧葡萄糖正电子发射断层扫描或铊 - 201再注射提供一种替代的、准确且经济有效的方法，用于识别受损或功能失调但存活的心肌。
