新双源CT冠状动脉CTA不同扫描参数与重建算法获得图像质量的体模研究

目的 探讨基于原始数据域的迭代重建(SAFIRE)算法与滤波反投影(FBP)算法冠状动脉CT血管造影(CCTA)图像质量的差异。方法 对置入模拟左、右冠状动脉的仿真体模,采用两组管电压(100 kV、120 kV)行双源CT检查,对冠状动脉原始图像在工作站上分别进行FBP及SAFIRE两种算法的图像重建,对不同管电压及不同管电流组内图像质量指标SNR、CNR、CT值标准差进行t检验;相同管电压不同重建算法,不同管电压相同管电流SAFIRE重建方式的两组SNR、CNR、CT值标准差及CT值采用配对t检验。结果 两组管电压扫描后经SAFIRE重建的冠状动脉图像质量均明显优于FBP重建;两组管电压两种重建算法图像,随着管电流的增加,200~360 mA图像质量呈改善趋势,管电流340 mA及以上图像质量指标趋于稳定;不同管电压相同管电流SAFIRE重建算法成像其图像质量比较,CNR、SNR、CT值标准差差异均有统计学意义(t=5.36、2.49、21.82,P均<0.05)。结论 随着扫描参数(管电流与管电压)的增加,图像质量随之上升,但到达一定值后图像质量趋于稳定;采用SAFIRE在相同扫描条件下可以明显提高图像质量。

Imaging quality of coronary computed tomography angiography with different parameters and reconstruction algorithm using anthropomorphic chest phantom on new DSCT

Objective To investigate the differences of imaging quality of coronary computed tomography angiography (CCTA) between iterative reconstructions based on the original data and filtered back projection (FBP). Methods A Chinese anthropomorphic chest phantom with simulated coronary arteries underwent CCTA using different scan parameters (tube voltage 100 kV and 120 kV). The CCTA scan, data sets of two groups were reconstructed with Sinogram Affirmed Iterative reconstruction (SAFIRE) and FBP. The indicators of imaging quality (SNR, CNR, SD of CT value) in each group were compared by Dunnett t test. The paired t-test was conducted to analyze the imaging quality of the same tube voltage of different reconstruction algorithms and the same reconstruction algorithms of different tube voltage by SAFIRE. Results The imaging quality of SAFIRE reconstruction was higher than that of FBP reconstruction. With tube current from 200 mA to 360 mA, imaging quality increased, which showing linear tendency. When tube current was 340 mA or more, the imaging quality was stable. Statistical significances between the two groups (100 kV, 120 kV) of SNR, CNR, SD of CT value by SAFIRE were found (t=5.36, 2.49, 21.82, all P<0.05). Conclusion With the increase of tube voltage and tube current, the imaging quality go better gradually, but when tube current is 340 mA or more, the imaging quality become stable. SAFIRE can significantly improve imaging quality under the same scanning condition.