Translational and Molecular Imaging, Mount Sinai School of Medicine, New York, NY 10029, USA.
Invest Radiol. 2012 Aug;47(8):475-81. doi: 10.1097/RLI.0b013e3182562ab9.
Gold nanoparticles (gold-NPs) have lately been proposed as alternative contrast agents to iodine-based contrast agents (iodine-CA) for computed tomography (CT) angiography. The aims of this study were to confirm an appropriate environment in which to evaluate such novel contrast agents, to investigate the comparative contrast of iodine-CA versus gold-NP, and to determine optimal scanning parameters for gold-NP.
Three different clinical scanners were used to acquire CT images. A range of concentrations (10 mM to 1.5 M) of gold-NP and iodine-CA were scanned with varying x-ray tube voltages and currents, reconstruction kernels, protocols, and scanner models. The different environments investigated were air, water, and water with a bone simulant (Ca3(PO4)2). Regression coefficients were derived from the attenuation values plotted against concentration and compared for statistical significance using t values.
As expected, contrast was linearly related to concentrations up to 500 to 1000 mM, depending on the conditions used, whereupon a plateau of 3000 Hounsfield units was reached. Attenuation was significantly different depending on the environment used (air, water, or water and bone simulant). Contrast is dependent on the x-ray tube voltage used, with the contrast produced from iodine-CA sharply declining with increasing voltage, whereas the contrast of gold-NP varied less with tube voltage but was maximal at 120 kV in water with bone simulant. Current, reconstruction kernels, protocols, and scanner model had less effect on contrast.
Water with a bone simulant is a preferable environment for evaluating novel cardiac CT contrast agents. Relative iodine-CA versus gold-NP contrast is dependent on the scanning conditions used. Optimal scanning conditions for gold-NP will likely use an x-ray tube voltage of 120 kV.
金纳米粒子（gold-NPs）最近被提议作为计算机断层扫描（CT）血管造影中碘基对比剂（iodine-CA）的替代对比剂。本研究的目的是确认一个合适的环境来评估这种新型对比剂，研究碘对比剂与金纳米粒子的对比，并确定金纳米粒子的最佳扫描参数。
使用三种不同的临床扫描仪获取 CT 图像。扫描了 gold-NP 和 iodine-CA 的一系列浓度（10mM 至 1.5M），使用不同的 X 射线管电压和电流、重建核、协议和扫描仪型号。研究了不同的环境，包括空气、水和含有骨模拟物（Ca3(PO4)2）的水。从衰减值与浓度的关系中得出回归系数，并使用 t 值比较其统计学意义。
正如预期的那样，根据使用的条件，对比度与浓度呈线性关系，最高可达 500 至 1000mM，随后达到 3000 亨斯菲尔德单位的平台。衰减值因使用的环境而异（空气、水或水和骨模拟物）。对比剂的产生依赖于使用的 X 射线管电压，碘对比剂的对比度随电压的升高而急剧下降，而金纳米粒子的对比度随电压的变化较小，但在含有骨模拟物的水中在 120kV 时达到最大值。电流、重建核、协议和扫描仪型号对对比度的影响较小。
含有骨模拟物的水是评估新型心脏 CT 对比剂的首选环境。碘对比剂与金纳米粒子的相对对比度取决于使用的扫描条件。金纳米粒子的最佳扫描条件可能使用 120kV 的 X 射线管电压。
