BACKGROUND Technetium-99 m pyrophosphate protocols for transthyretin cardiac amyloidosis diagnosis have variably used 1- and 3-hour imaging time points. We investigated whether imaging at 1 hour with superior efficiency had comparable diagnostic accuracy as 3-hour imaging. METHODS This is a registry analysis of patients with suspected transthyretin cardiac amyloidosis referred for technetium-99 m pyrophosphate at a single tertiary center from June 2015 through January 2019. Patients underwent planar and single-photon emission computed tomography (SPECT) imaging at 1 and 3 hours. A positive Tc-99m pyrophosphate study was defined by the presence of diffuse myocardial tracer uptake on SPECT. For planar imaging, visual semiquantitative (grades 0-3, ≥2 considered positive) and quantitative heart to contralateral ratios (≥1.5 considered positive) were used. RESULTS Two hundred thirty-three patients (69% men; median age, 77 [69-83] years) underwent the study protocol. There were 60 (25.8%) patients with diffuse myocardial uptake, 1 (0.4%) with regional uptake, and 172 (73.8%) with no myocardial uptake. Results of SPECT were identical at 1 and 3 hours. Planar imaging at 1 hour had 98% sensitivity and 96% specificity. Planar grade 0 uptake or heart to contralateral ratio ≤1.2 and planar grade 3 uptake or heart to contralateral ratio ≥2.0 were always associated with negative and positive SPECT, respectively. For planar grades 1 and 2 uptake and heart to contralateral ratio 1.3 to 1.9, SPECT was needed to make a diagnosis. No patient with light-chain cardiac amyloidosis had positive SPECT. CONCLUSIONS An efficient 1-hour technetium-99 m pyrophosphate protocol had comparable diagnostic performance to a 3-hour protocol.

中文翻译：

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高效的1小时Tech- 99 m焦磷酸盐成像协议，用于甲状腺运甲状腺素蛋白心脏淀粉样变性的诊断。

背景技术用于甲状腺素转运蛋白心脏淀粉样变性诊断的99m焦磷酸盐方案已可变地使用了1小时和3小时成像时间点。我们调查了1小时高效成像是否具有与3小时成像相当的诊断准确性。方法这是对2015年6月至2019年1月在单个三级中心因可疑转甲状腺素蛋白淀粉样变性而被推荐使用tech99 m焦磷酸盐的患者的注册表分析。患者在第1和第3接受平面和单光子发射计算机断层扫描（SPECT）成像小时。Tc-99m焦磷酸盐的阳性研究定义为SPECT上存在弥漫性心肌示踪剂摄取。对于平面成像，视觉半定量（0-3级，≥2被认为是阳性），定量的心对侧比率（≥1）。使用5个阳性）。结果233例患者（男性占69％；中位年龄为77 [69-83]岁）接受了研究方案。有60例（25.8％）的患者有弥漫性心肌摄取，有1例（0.4％）有区域性摄取，而172例（73.8％）没有心肌摄取。在1小时和3小时时，SPECT的结果相同。1小时的平面成像灵敏度为98％，特异性为96％。平面0级摄取或心对侧比率≤1.2和平面3级摄取或心对侧比率≥2.0分别与SPECT阴性和阳性相关。对于平面1级和2级摄取以及心对侧比率1.3至1.9，需要进行SPECT诊断。轻链心脏淀粉样变性患者均无SPECT阳性。