Kubo Takeshi, Ohno Kishimoto Ayami, Togashi Kaori
Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
Eur J Radiol Open. 2019 Mar 11;6:113-118. doi: 10.1016/j.ejro.2019.02.001. eCollection 2019.
To determine the reproducibility and productivity of reduced dose chest computed tomography (CT) using a nodule detection task.
Eighty-eight consecutive non-contrast CT examinations were performed using an automatic exposure system with a reference standard deviation of 8.5. Simulated raw data of a reduced dose scan (standard deviation at 21 and 29) were generated with a dose simulator. Original and simulated raw data were reconstructed to series of 7-mm-thick images (Original, Simulation A, Simulation B). In the first part of the reading experiment, three readers independently interpreted these images (88 cases × 3 series) and recorded the size, type, and location of the pulmonary nodules. The reading time for every case was recorded. In the second part of the experiment, the repeated interpretation of standard dose images was performed by two readers. Concordance or discordance of nodule detection between the first and the repeated reading result was assessed.
A statistically significant difference in the detected nodule counts for lesions less than 5 mm by one reader was observed in simulation B images. Discordance of the interpretation result was found only in ground-glass nodules larger than 5 mm detected by one reader in simulation B images. There was no statistically significant difference in the reading time among the three image types.
Simulated standard deviation 21 images can reproduce the image interpretation result of original images, whereas simulated standard deviation 29 images may compromise the accuracy of nodule assessment. The effect on the reading time was not observed with dose reduction simulation.
使用结节检测任务来确定低剂量胸部计算机断层扫描（CT）的可重复性和效率。
使用具有8.5参考标准差的自动曝光系统进行了88次连续的非增强CT检查。用剂量模拟器生成了低剂量扫描的模拟原始数据（标准差分别为21和29）。将原始和模拟原始数据重建为7毫米厚的图像系列（原始图像、模拟A、模拟B）。在阅读实验的第一部分，三名读者独立解读这些图像（88例×3个系列），并记录肺结节的大小、类型和位置。记录每个病例的阅读时间。在实验的第二部分，由两名读者对标准剂量图像进行重复解读。评估首次和重复阅读结果之间结节检测的一致性或不一致性。
在模拟B图像中，一名读者检测到的小于5毫米病变的结节数量存在统计学显著差异。仅在模拟B图像中一名读者检测到的大于5毫米的磨玻璃结节中发现解读结果不一致。三种图像类型的阅读时间没有统计学显著差异。
模拟标准差21的图像可以重现原始图像的图像解读结果，而模拟标准差29的图像可能会损害结节评估的准确性。剂量降低模拟未观察到对阅读时间的影响。
