Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC 29401, USA.
Radiology. 2012 Sep;264(3):700-7. doi: 10.1148/radiol.12112455. Epub 2012 Jul 24.
To evaluate the feasibility of using virtual noncontrast material-enhanced (VNC) computed tomographic (CT) series derived from dual-energy CT imaging studies for coronary artery calcium quantification.
This HIPAA-compliant study was institutional review board approved; all patients provided written informed consent. Thirty-six patients prospectively underwent noncontrast-enhanced CT calcium scoring followed by coronary CT angiography performed in dual-energy mode. By using different reconstruction algorithms, three VNC series were generated and evaluated for noise and efficiency of virtual iodine removal. Two readers independently quantified calcium on VNC images and true noncontrast-enhanced conventional calcium scoring series. A leave-one-out cross validation was used to assess the accuracy of calcium score prediction from VNC series by means of linear regression.
CT value histograms of the VNC series closely resembled the profile in the true noncontrast-enhanced series. There was excellent correlation between calcium volumes on the VNC series and true noncontrast-enhanced series on a per-patient (r = 0.94, P < .001, n = 36) and per-vessel (r = 0.94, 0.91, and 0.92 for the three coronary arteries, all P < .001, n = 36 each) level. The ability of a linear regression model to predict actual calcium scores from calcium volumes on VNC series was excellent (r = 0.82). Multiethnic Study of Atherosclerosis rankings that were derived from the predicted calcium scores also showed excellent agreement (intraclass correlation coefficient = 0.909).
Coronary artery calcium identification and quantification based on dual-energy coronary CT angiographic studies may obviate the need for dedicated CT calcium scoring studies.
评估利用双能 CT 成像研究中的虚拟非增强（VNC）物质 CT 系列进行冠状动脉钙定量的可行性。
本 HIPAA 合规性研究获得机构审查委员会批准；所有患者均提供书面知情同意书。36 例患者前瞻性地接受非增强 CT 钙评分检查，随后进行双能 CT 血管造影检查。通过使用不同的重建算法，生成了三个 VNC 系列，并对其噪声和虚拟碘去除效率进行了评估。两位读者独立对 VNC 图像和真实非增强常规钙评分系列进行了钙定量。采用交叉验证方法，通过线性回归评估 VNC 系列预测钙评分的准确性。
VNC 系列的 CT 值直方图与真实非增强系列的轮廓非常相似。VNC 系列和真实非增强系列的钙体积之间存在极好的相关性，在患者层面（r = 0.94，P <.001，n = 36）和血管层面（r = 0.94、0.91 和 0.92，三条冠状动脉，均 P <.001，n = 36）均如此。线性回归模型从 VNC 系列的钙体积预测实际钙评分的能力非常出色（r = 0.82）。从预测钙评分中得出的多民族动脉粥样硬化研究分级也显示出极好的一致性（组内相关系数 = 0.909）。
基于双能冠状动脉 CT 血管造影研究的冠状动脉钙识别和定量可能无需专门的 CT 钙评分研究。
