Department of Thoracic Imaging, Hôpital Calmette (EA 2694 Université Lille Nord de France, Boulevard Jules Leclercq, 59037 Lille, France.
Radiology. 2013 Apr;267(1):256-66. doi: 10.1148/radiol.12120195. Epub 2013 Jan 14.
To determine the energy levels that provide optimal imaging of thoracic circulation at dual-energy computed tomographic (CT) angiography with reduced iodine load in comparison with a standard technique.
The institutional review board approved the study with waiver of patient consent. Eighty patients underwent a dual-source, dual-energy CT examination after administration of low-concentration contrast material (170 mg of iodine per milliliter), and eight series of images were reconstructed, including the original polychromatic images at 80 and 140 kV and six series of virtual monochromatic spectral images at 50, 60, 70, 80, 90, and 100 keV. For each vascular compartment, the energy level that provided optimal evaluation on virtual monochromatic spectral images was determined, and these series were compared with the polychromatic dual-energy images and with standard chest CT images that were used as controls. Comparisons between groups were performed by using the paired Student t test for continuous variables and the McNemar test for categorical variables. Comparisons between dual-energy and standard CT images were performed by using the unpaired Student t test for continuous variables and the χ(2) test for categorical variables.
For the aorta, pulmonary arteries, and veins, the reconstruction at 60 keV provided adequate attenuation without marked beam-hardening artifacts in 90% of patients, with the highest contrast-to-noise and signal-to-noise ratios, the lowest level of subjective noise, and no significant differences with images at 80 kV (mean energy, 54 keV). For the superior vena cava and brachiocephalic veins, the reconstructions at 100 keV enabled artifact-free analysis of the perivascular anatomic zone without a significant difference with images at 140 kV (mean energy, 92 keV). Compared with standard CT images acquired after administration of a 35% iodinated contrast agent, there was a statistically significant reduction in the frequency of artifacts around systemic veins at 100 keV (P < .001) and similar overall image quality for central vessels at 60 keV (P > .05).
An optimal analysis of thoracic circulation can be achieved on virtual monochromatic spectral images at 60 keV and 100 keV and on the original polychromatic images at 80 kV and 140 kV.
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120195/-/DC1.
与标准技术相比，确定在双能 CT 血管造影中使用低浓度碘负荷提供最佳胸部循环成像的能量水平。
本研究经机构审查委员会批准豁免患者知情同意。80 例患者接受双源双能 CT 检查，给予低浓度对比剂（每毫升 170 毫克碘），重建 8 个系列图像，包括原始多色图像（80kV 和 140kV）和 6 个系列虚拟单色光谱图像（50keV、60keV、70keV、80keV、90keV 和 100keV）。对于每个血管腔室，确定提供最佳虚拟单色光谱图像评估的能量水平，并将这些系列与多色双能图像和作为对照的标准胸部 CT 图像进行比较。通过连续变量的配对学生 t 检验和分类变量的 McNemar 检验比较组间差异。通过连续变量的独立学生 t 检验和分类变量的 χ²检验比较双能和标准 CT 图像之间的差异。
对于主动脉、肺动脉和静脉，60keV 重建可提供 90%患者的足够衰减，无明显束硬化伪影，具有最高的对比噪声比和信噪比，最低的主观噪声水平，与 80kV 图像无显著差异（平均能量 54keV）。对于上腔静脉和头臂静脉，100keV 重建可实现血管周围解剖区无伪影分析，与 140kV 图像无显著差异（平均能量 92keV）。与给予 35%碘造影剂后获得的标准 CT 图像相比，100keV 时系统静脉周围伪影的频率有统计学显著降低（P<.001），60keV 时中心血管的整体图像质量相似（P>.05）。
在 60keV 和 100keV 的虚拟单色光谱图像以及 80kV 和 140kV 的原始多色图像上可实现最佳的胸部循环分析。
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120195/-/DC1.
