Marsh Jeffrey F, VanMeter Patrick D, Rajendran Kishore, Leng Shuai, McCollough Cynthia H
Mayo Clinic, Department of Radiology, Rochester, Minnesota, United States.
J Med Imaging (Bellingham). 2023 Jul;10(4):043501. doi: 10.1117/1.JMI.10.4.043501. Epub 2023 Jul 4.
Coronary artery calcification (CAC) is an important indicator of coronary disease. Accurate volume quantification of CAC is challenging using computed tomography (CT) due to calcium blooming, which is a consequence of limited spatial resolution. coronary specimens were scanned on an ultra-high-resolution (UHR) clinical photon-counting detector (PCD) CT scanner, and the accuracy of CAC volume estimation was compared with a state-of-the-art conventional energy-integrating detector (EID) CT, a previous-generation investigational PCD-CT, and micro-CT.
CAC specimens () were scanned on EID-CT and PCD-CT using matched parameters (120 kV, 9.3 mGy ). EID-CT images were reconstructed using our institutional routine clinical protocol for CAC quantification. UHR PCD-CT data were reconstructed using a sharper kernel. An image-based denoising algorithm was applied to the PCD-CT images to achieve similar noise levels as EID-CT. Micro-CT images served as the volume reference standard. Calcification images were segmented, and their volume estimates were compared. The CT data were further compared with previous work using an investigational PCD-CT.
Compared with micro-CT, CT volume estimates had a mean absolute percent error of for clinical PCD-CT, for EID-CT, and for previous-generation PCD-CT. Clinical PCD-CT absolute percent error was significantly () lower than both EID-CT and previous generation PCD-CT. The mean calcification CT number and contrast-to-noise ratio were both significantly () higher in clinical PCD-CT relative to EID-CT.
UHR clinical PCD-CT showed reduced calcium blooming artifacts and further enabled improved accuracy of CAC quantification beyond that of conventional EID-CT and previous generation PCD-CT systems.
冠状动脉钙化（CAC）是冠心病的一项重要指标。由于钙化伪影（这是空间分辨率有限的结果），使用计算机断层扫描（CT）对CAC进行准确的体积定量具有挑战性。对冠状动脉标本在超高分辨率（UHR）临床光子计数探测器（PCD）CT扫描仪上进行扫描，并将CAC体积估计的准确性与最先进的传统能量积分探测器（EID）CT、上一代研究用PCD-CT以及微型CT进行比较。
使用匹配参数（120 kV，9.3 mGy）在EID-CT和PCD-CT上对CAC标本进行扫描。EID-CT图像使用我们机构用于CAC定量的常规临床方案进行重建。UHR PCD-CT数据使用更锐利的内核进行重建。对PCD-CT图像应用基于图像的去噪算法，以达到与EID-CT相似的噪声水平。微型CT图像用作体积参考标准。对钙化图像进行分割，并比较它们的体积估计值。将CT数据与之前使用研究用PCD-CT的工作进行进一步比较。
与微型CT相比，临床PCD-CT的CT体积估计平均绝对百分比误差为 ，EID-CT为 ，上一代PCD-CT为 。临床PCD-CT的绝对百分比误差显著（ ）低于EID-CT和上一代PCD-CT。相对于EID-CT，临床PCD-CT的平均钙化CT值和对比噪声比均显著（ ）更高。
UHR临床PCD-CT显示出减少的钙化伪影，并且进一步提高了CAC定量的准确性，超过了传统EID-CT和上一代PCD-CT系统。
