Li Qin, Liu Songtao, Myers Kyle J, Gavrielides Marios A, Zeng Rongping, Sahiner Berkman, Petrick Nicholas
U.S. Food and Drug Administration, CDRH/OSEL/DIDSR, 10903 New Hampshire Ave., Bldg. 62 Rm. 4110, Silver Spring, MD 20993.
U.S. Food and Drug Administration, CDRH/OIR/DRH, Silver Spring, Maryland.
Acad Radiol. 2016 Dec;23(12):1470-1479. doi: 10.1016/j.acra.2016.08.014. Epub 2016 Sep 22.
Different computed tomography imaging protocols and patient characteristics can impact the accuracy and precision of the calcium score and may lead to inconsistent patient treatment recommendations. The aim of this work was to determine the impact of reconstruction algorithm and gender characteristics on coronary artery calcium scoring based on a phantom study using computed tomography.
Four synthetic heart vessels with vessel diameters corresponding to female and male left main and left circumflex arteries containing calcification-mimicking materials (200-1000 HU) were inserted into a thorax phantom and were scanned with and without female breast plates (male and female phantoms, respectively). Ten scans were acquired and were reconstructed at 3-mm slices using filtered-back projection (FBP) and iterative reconstruction with medium and strong denoising (IR3 and IR5) algorithms. Agatston and calcium volume scores were estimated for each vessel. Calcium scores for each vessel and the total calcium score (summation of all four vessels) were compared between the two phantoms to quantify the impact of the breast plates and reconstruction parameters. Calcium scores were also compared among vessels of different diameters to investigate the impact of the vessel size.
The calcium scores were significantly larger for FBP reconstruction (FBP > IR3>IR5). Agatston scores (calcium volume score) for vessels in the male phantom scans were on average 4.8% (2.9%), 8.2% (7.1%), and 10.5% (9.4%) higher compared to those in the female phantom with FBP, IR3, and IR5, respectively, when exposure was conserved across phantoms. The total calcium scores from the male phantom were significantly larger than those from the female phantom (P <0.05). In general, calcium volume scores were underestimated (up to about 50%) for smaller vessels, especially when scanned in the female phantom.
Calcium scores significantly decreased with iterative reconstruction and tended to be underestimated for female anatomy (smaller vessels and presence of breast plates).
不同的计算机断层扫描成像方案和患者特征会影响钙评分的准确性和精确性，并可能导致患者治疗建议不一致。本研究的目的是通过使用计算机断层扫描的体模研究，确定重建算法和性别特征对冠状动脉钙化评分的影响。
将四个合成心脏血管插入胸部体模中，这些血管直径分别对应女性和男性的左主干和左旋支动脉，并含有模拟钙化的材料（200 - 1000 HU），分别在有和没有女性乳房板的情况下进行扫描（分别为男性和女性体模）。采集了10次扫描图像，并使用滤波反投影（FBP）以及具有中等和强去噪功能的迭代重建（IR3和IR5）算法在3毫米切片上进行重建。对每个血管估计阿加斯顿评分和钙体积评分。比较两个体模中每个血管的钙评分以及总钙评分（四个血管的总和），以量化乳房板和重建参数的影响。还比较不同直径血管之间的钙评分，以研究血管大小的影响。
FBP重建的钙评分显著更高（FBP > IR3 > IR5）。当在不同体模间保持相同曝光量时，男性体模扫描中血管的阿加斯顿评分（钙体积评分）分别比女性体模中使用FBP、IR3和IR5时平均高4.8%（2.9%）、8.2%（7.1%）和10.5%（9.4%）。男性体模的总钙评分显著高于女性体模（P < 0.05）。一般来说，较小血管的钙体积评分被低估（高达约50%），尤其是在女性体模中扫描时。
迭代重建时钙评分显著降低，并且对于女性解剖结构（较小血管和存在乳房板）往往被低估。
