To intra-individually investigate the variation of coronary artery calcium (CAC), aortic valve calcium (AVC), and mitral annular calcium (MAC) scores and the presence of blur artifacts as a function of temporal resolution in patients undergoing non-contrast cardiac CT on a dual-source photon counting detector (PCD) CT. This retrospective, IRB-approved study included 70 patients (30 women, 40 men, mean age 78 ± 9 years) who underwent ECG-gated cardiac non-contrast CT with PCD-CT (gantry rotation time 0.25 s) prior to transcatheter aortic valve replacement. Each scan was reconstructed at a temporal resolution of 66 ms using the dual-source information and at 125 ms using the single-source information. Average heart rate and heart rate variability were calculated from the recorded ECG. CAC, AVC, and MAC were quantified according to the Agatston method on images with both temporal resolutions. Two readers assessed blur artifacts using a 4-point visual grading scale. The influence of average heart rate and heart rate variability on calcium quantification and blur artifacts of the respective structures were analyzed by linear regression analysis. Mean heart rate and heart rate variability during data acquisition were 76 ± 17 beats per minute (bpm) and 4 ± 6 bpm, respectively. CAC scores were smaller on 66 ms (median, 511; interquartile range, 220–978) than on 125 ms reconstructions (538; 203–1050, p < 0.001). Median AVC scores [2809 (2009–3952) versus 3177 (2158–4273)] and median MAC scores [226 (0-1284) versus 251 (0-1574)] were also significantly smaller on 66ms than on 125ms reconstructions (p < 0.001). Reclassification of CAC and AVC risk categories occurred in 4% and 11% of cases, respectively, whereby the risk category was always overestimated on 125ms reconstructions. Image blur artifacts were significantly less on 66ms as opposed to 125 ms reconstructions (p < 0.001). Intra-individual analyses indicate that temporal resolution significantly impacts on calcium scoring with cardiac CT, with CAC, MAC, and AVC being overestimated at lower temporal resolution because of increased motion artifacts eventually leading to an overestimation of patient risk.

个体内部研究接受非造影心脏 CT 的患者冠状动脉钙 (CAC)、主动脉瓣钙 (AVC) 和二尖瓣环钙 (MAC) 评分的变化以及模糊伪影随时间分辨率的变化在双源光子计数探测器 (PCD) CT 上。这项经 IRB 批准的回顾性研究纳入了 70 名患者（30 名女性，40 名男性，平均年龄 78 ± 9 岁），他们在经导管主动脉瓣置换术之前接受了心电图门控心脏非增强 CT 和 PCD-CT（机架旋转时间 0.25 秒）替代品。每次扫描均使用双源信息以 66 ms 的时间分辨率重建，使用单源信息以 125 ms 的时间分辨率重建。根据记录的心电图计算平均心率和心率变异性。CAC、AVC 和 MAC 根据 Agatston 方法对具有两种时间分辨率的图像进行量化。两名读者使用 4 点视觉分级量表评估模糊伪影。通过线性回归分析分析平均心率和心率变异性对钙定量和各个结构的模糊伪影的影响。数据采集​​期间的平均心率和心率变异性分别为 76 ± 17 次/分钟 (bpm) 和 4 ± 6 bpm。66 ms 的 CAC 评分（中位数，511；四分位数范围，220-978）小于 125 ms 重建的 CAC 评分（538；203-1050，p  < 0.001）。66ms 重建的中位 AVC 评分 [2809 (2009–3952) 对比 3177 (2158–4273)] 和中位 MAC 评分 [226 (0-1284) 对比 251 (0-1574)] 也显着小于 125ms 重建 ( p  < 0.001）。CAC 和 AVC 风险类别的重新分类分别发生在 4% 和 11% 的案例中，其中风险类别在 125ms 重建时总是被高估。与 125 毫秒重建相比，66 毫秒的图像模糊伪影明显减少 ( p  < 0.001)。个体内分析表明，时间分辨率对心脏 CT 的钙评分有显着影响，CAC、MAC 和 AVC 在较低时间分辨率下被高估，因为运动伪影增加，最终导致患者风险的高估。