Department of Nuclear Medicine, Medical Center-University of Freiburg, Freiburg, Germany; and
Department of Nuclear Medicine, Medical Center-University of Freiburg, Freiburg, Germany; and.
J Nucl Med. 2019 Dec;60(12):1764-1770. doi: 10.2967/jnumed.119.227132. Epub 2019 Apr 26.
We evaluated the effect of a reduced acquisition time for F-FDG PET studies of Alzheimer dementia (AD) and frontotemporal dementia (FTD) to derive a limit for reductions of acquisition time (improving patient compliance) and administered activity (lowering the radiation dose) with uncompromised diagnostic outcome. We included patients with a clinical diagnosis of AD ( = 13) or FTD ( = 12) who were examined with F-FDG PET/CT after injection of 210 ± 9 MBq of F-FDG. List-mode data were reconstructed over various time intervals simulating reduced acquisition times or administered activities. Volume-of-interest-based and voxelwise statistical analyses including group contrasts were performed for 15 different acquisition times ranging from 10 min to 2 s. In addition, masked visual reads were obtained from 3 readers independently for 7 different acquisition times down to 30 s, providing a diagnosis of either AD or FTD and the individual diagnostic certainty. Regional mean uptake changed by less than 5% at a reduced acquisition time down to 1 min in all regions and patients except for the posterior cingulate cortex of 1 patient. Voxelwise group contrasts suggest a sufficient measurement time of only 2 min, for which the number of significant voxels decreased by merely 5% while maintaining their spatial pattern. In 450 visual reads at reduced times, no change in the original diagnosis was observed. The diagnostic certainty showed only a very slow and mild decline, with small effect sizes (Cohen's d) of 0.3, at acquisition times of 3 and 2 min compared with the original results at 10 min. Statistical results at a region and voxel level, as well as single-subject visual reads, reveal a considerable potential to reduce the typical 10-min acquisition time (by a factor of 4) without compromising diagnostic quality. Conversely, our data suggest that for a given acquisition time of 10 min and a similar effect size, the administered activity may be reduced to 50 MBq, resulting in an effective dose of less than 1 mSv for the PET examination.
我们评估了减少阿尔茨海默病（AD）和额颞叶痴呆（FTD）的 F-FDG PET 研究采集时间的效果，以确定降低采集时间（提高患者依从性）和放射性活度（降低辐射剂量）的限制，同时不影响诊断结果。我们纳入了经临床诊断为 AD（n = 13）或 FTD（n = 12）的患者，在注射 210 ± 9 MBq F-FDG 后进行 F-FDG PET/CT 检查。模拟减少采集时间或放射性活度的列表模式数据，在不同的时间间隔内进行重建。对 15 种不同的采集时间（从 10 分钟到 2 秒）进行基于感兴趣区域和体素的统计分析，包括组对比。此外，从 3 位独立的读者那里获得了 7 种不同采集时间（低至 30 秒）的掩蔽视觉读数，提供了 AD 或 FTD 的诊断和个体诊断确定性。除了 1 名患者的后扣带回外，在所有区域和患者中，在减少采集时间至 1 分钟时，区域平均摄取量的变化小于 5%。体素水平的组对比表明，仅需 2 分钟的测量时间即可，此时，显著体素的数量仅减少了 5%，同时保持了其空间模式。在减少时间的 450 次视觉读数中，没有观察到原始诊断的变化。与 10 分钟时的原始结果相比，在采集时间为 3 分钟和 2 分钟时，诊断确定性仅显示出非常缓慢和温和的下降，效应量（Cohen's d）较小，为 0.3。在区域和体素水平的统计结果以及单个患者的视觉读数中，都揭示了在不影响诊断质量的情况下，减少典型的 10 分钟采集时间（减少 4 倍）的相当大的潜力。相反，我们的数据表明，对于给定的 10 分钟采集时间和类似的效应量，放射性活度可降低至 50 MBq，使 PET 检查的有效剂量低于 1 mSv。
