Case Western Reserve University, Department of Biomedical Engineering, 10900 Euclid Ave, Cleveland, OH, 44106, United States.
GE Healthcare, Waukesha, WI, 53188, United States.
Comput Med Imaging Graph. 2018 Mar;64:12-21. doi: 10.1016/j.compmedimag.2018.01.004. Epub 2018 Jan 11.
We have developed a technique to image coronary calcium, an excellent biomarker for atherosclerotic disease, using low cost, low radiation dual energy (DE) chest radiography, with potential for widespread screening from an already ordered exam. Our dual energy coronary calcium (DECC) processing method included automatic heart silhouette segmentation, sliding organ registration and scatter removal to create a bone-image-like, coronary calcium image with significant reduction in motion artifacts and improved calcium conspicuity compared to standard, clinically available DE processing. Experiments with a physical dynamic cardiac phantom showed that DECC processing reduced 73% of misregistration error caused by cardiac motion over a wide range of heart rates and x-ray radiation exposures. Using the functional measurement test (FMT), we determined significant image quality improvement in clinical images with DECC processing (p < 0.0001), where DECC images were chosen best in 94% of human readings. Comparing DECC images to registered and projected CT calcium images, we found good correspondence between the size and location of calcification signals. In a very preliminary coronary calcium ROC study, we used CT Agatston calcium score >50 as the gold standard for an actual positive test result. AUC performance was significantly improved from 0.73 ± 0.14 with standard DE to 0.87 ± 0.10 with DECC (p = 0.0095) for this limited set of surgical patient data biased towards heavy calcifications. The proposed DECC processing shows good potential for coronary calcium detection in DE chest radiography, giving impetus for a larger clinical evaluation.
我们开发了一种使用低成本、低辐射双能（DE）胸部射线摄影术对冠状动脉钙成像的技术，这是动脉粥样硬化疾病的一个极好的生物标志物，具有从已订购的检查中进行广泛筛查的潜力。我们的双能冠状动脉钙（DECC）处理方法包括自动心脏轮廓分割、滑动器官配准和散射去除，以创建一种类似于骨骼的冠状动脉钙图像，与标准的、临床可用的 DE 处理相比，运动伪影显著减少，钙对比度提高。使用物理动态心脏体模的实验表明，DECC 处理可将因心脏运动引起的配准误差降低 73%，适用的心率和 X 射线辐射范围很广。使用功能测量测试（FMT），我们确定了 DECC 处理后临床图像的质量有显著提高（p<0.0001），在 94%的人类阅读中，DECC 图像被选为最佳图像。将 DECC 图像与已注册和投影的 CT 钙图像进行比较，我们发现钙化信号的大小和位置之间有很好的对应关系。在一项非常初步的冠状动脉钙 ROC 研究中，我们使用 CT Agatston 钙评分>50 作为实际阳性测试结果的金标准。对于偏向重度钙化的手术患者的有限数据集，AUC 性能从标准 DE 的 0.73±0.14 显著提高到 DECC 的 0.87±0.10（p=0.0095）。该研究表明，DECC 处理在 DE 胸部射线摄影术对冠状动脉钙检测具有良好的应用潜力，为更大规模的临床评估提供了动力。
