头颅双能量CTA扫描参数组合与重建算法对图像质量影响的实验研究  

Impact of image quality with scan parameters and reconstruction algorithms in head dual-energy computed tomography angiography

作　　者：彭刚[1] 曾勇明[1] 郁仁强[1] 王杰[1] 

机构地区：[1]重庆医科大学附属第一医院放射科,400016

出　　处：《重庆医学》2016年第16期2236-2238,2241,共4页Chongqing medicine

基　　金：国家临床重点专科建设项目([2013]544)

摘　　要：目的应用不同重建算法行头颅双能量CT血管造影(DECTA)的图像质量,评价不同管电压组合行DECTA的辐射剂量。方法对置入模拟脑血管的头颅仿真体模,采用80/140kV和100/140kV行双能量CT扫描后,分别进行滤波反投影法(FBP)及迭代重建技术(SAFIRE)两种算法重建图像,测量CT值及CT值标准差(SD)计算信噪比(SNR)、对比噪育化(CNR),记录剂量长度乘积(DLP)并计算有效剂量,评价不同成像条件的图像质量及辐射剂量。结果在相同扫描参数条件下,SAFIRE重建算法的图像噪声明显低于FBP重建算法;随着管电流量从100mAs增加至300mAs,图像质量呈改善趋势,260mAs以上图像质量趋于稳定;采用SAFIRE重建算法,对两组管电压的图像质量进行比较,CT值SD差异有统计学意义(P<0.05),CNR和SNR差异无统计学意义(P>0.05);80/140kV组的有效剂量较100/140kV组明显降低。结论双能量头颅CTA采用80/140kV管电压组合结合SAFIRE算法能保证图像质量并显著降低辐射剂量。Objective To study the difference of image quality which based on different reconstruction in head dual-energy computed tomography angiography （DECTA） scanning,and evaluate the radiation dose which using different tube voltage in DECTA. Methods An anthropomorphic head phantom with simulated arteries was used for DECTA scanning by different scan parame- ters （tube voltage 80/140 kV and tube voltage 100/140 kV）, the data was reconstructed with filtered back projection （FBP） and Sinogram Affirmed Iterative Reconstruction （SAFIRE）. The CT values with SD were measured and calculate to SNR and CNR, the dose length product （DLP） was reeorded and invert to effective dose. The image quality and radiation dose were evaluated in different imaging condition. Results The image noise of SAFIRE reconstruction was lower than FBP reconstruction in same san parameters. The increase of tube current-time product from 100 mAs to 300 mAs,it shows the characteristics of linear tendency. When it was on 260 mAs,the image quality become stable. The difference between the two groups（80/140 kV, 100/140 kV）of SD of CT value by SAFIRE was significant （P〈0.05）, the difference of SNR and CNR between the two groups was not signifieant（P〉0.05）. The effective doses of group A （80/140 kV） was significantly lower than group B（100/140 kV）. Conclusion Using tube voltage of 80/140 kV combine with SAFIRE algorithm in head DECTA can ensure the image quality, which can significantly reduce radiation dose.

关 键 词：体层摄影术 X线计算机 双能 迭代重建 图像质量 

分 类 号：R816.1[医药卫生—放射医学]