Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Division of Cardiology and Structural Heart Diseases, Medical University of Silesiain , Katowice, Katowice, Poland.
Eur Radiol. 2023 Jul;33(7):4668-4675. doi: 10.1007/s00330-023-09434-1. Epub 2023 Feb 2.
To systematically assess the radiation dose reduction potential of coronary artery calcium (CAC) assessments with photon-counting computed tomography (PCCT) by changing the tube potential for different patient sizes with a dynamic phantom.
A hollow artery, containing three calcifications of different densities, was translated at velocities corresponding to 0, < 60, 60-75, and > 75 beats per minute within an anthropomorphic phantom. Extension rings were used to simulate average- and large -sized patients. PCCT scans were made with the reference clinical protocol (tube potential of 120 kilovolt (kV)), and with 70, 90, Sn100, Sn140, and 140 kV at identical image quality levels. All acquisitions were reconstructed at a virtual monoenergetic energy level of 70 keV. For each calcification, Agatston scores and contrast-to-noise ratios (CNR) were determined, and compared to the reference with Wilcoxon signed-rank tests, with p < 0.05 indicating significant differences.
A decrease in radiation dose (22%) was achieved at Sn100 kV for the average-sized phantom. For the large phantom, Sn100 and Sn140 kV resulted in a decrease in radiation doses of 19% and 3%, respectively. Irrespective of CAC density, Sn100 and 140 kVp did not result in significantly different CNR. Only at Sn100 kV were there no significant differences in Agatston scores for all CAC densities, heart rates, and phantom sizes.
PCCT at tube voltage of 100 kV with added tin filtration and reconstructed at 70 keV enables a ≥ 19% dose reduction compared to 120 kV, independent of phantom size, CAC density, and heart rate.
• Photon-counting CT allows for reduced radiation dose acquisitions (up to 19%) for coronary calcium assessment by reducing tube voltage while reconstructing at a normal monoE level of 70 keV. • Tube voltage reduction is possible for medium and large patient sizes, without affecting the Agatston score outcome.
通过在动态体模中改变不同患者体型的管电压，对光子计数 CT（PCCT）评估冠状动脉钙化（CAC）的辐射剂量降低潜力进行系统评估。
在体模内，一个空心动脉以对应于 0、<60、60-75 和>75 次/分钟的速度平移，其中包含三个不同密度的钙化。使用扩展环模拟平均体型和大体型患者。使用参考临床方案（管电压 120 千伏）以及 70、90、Sn100、Sn140 和 140 kV 进行 PCCT 扫描，图像质量水平相同。所有采集均在虚拟单能能量水平 70 keV 处重建。对于每个钙化，确定 Agatston 评分和对比噪声比（CNR），并与参考值进行 Wilcoxon 符号秩检验，p<0.05 表示差异有统计学意义。
对于平均体型体模，在 Sn100 kV 时可降低 22%的辐射剂量。对于大体型体模，Sn100 和 Sn140 kV 可分别降低 19%和 3%的辐射剂量。无论 CAC 密度如何，Sn100 和 140 kVp 均未导致 CNR 显著差异。只有在 Sn100 kV 时，对于所有 CAC 密度、心率和体模大小，Agatston 评分没有显著差异。
与 120 kV 相比，使用附加锡滤过的管电压 100 kV 的 PCCT 并在 70 keV 处重建可使冠状动脉钙化评估的辐射剂量降低≥19%，与体模大小、CAC 密度和心率无关。
• 光子计数 CT 通过降低管电压同时在正常的 70 keV 单能水平重建，可实现冠状动脉钙化评估的辐射剂量降低（最高可达 19%）。• 管电压降低适用于中大型患者，而不会影响 Agatston 评分结果。
