中文摘要：

目的：探讨基于原始数据迭代算法（Sonogram Affirmed Iterative Reconstruction,SAFIRE）的二代双源CT单能成像技术在腹部血管（门静脉）的成像质量评价。方法：对符合临床要求行上腹部增强CT扫描,且门静脉期行双能扫描的40例病患纳入研究。采用双能量单能谱软件得出门静脉主干对比信噪比（Contrast to Noise Ratio,CNR）能量变化曲线,得出最佳单能量点的单能图像。将扫描得到的门脉期图像数据进行3组不同函数的回顾重建：A组为最佳单能量＋滤波反投射（FBP）;B组为最佳单能量＋迭代SAFIRE-3级;C组为双能两球管（80 k V和140 k V）扫描完成后,自动加权生成的管电压为120 k V的门脉图像作为常规对照组,即120 k V＋FBP。在工作站上分别完成门静脉血管重建的最大密度投影,容积再现（Volume Rendering,VR）和多平面重建,并在门脉分支中心层面测量门静脉主干,肝实质结构的CT值和图像噪声值,并计算CNR值。由两位高年资放射科医生对门脉图像进行评价评分。结果：A、B、C三组的门脉CT值分别为（192.31±37.88）HU、（189.89±37.42）HU和（152.54±27.58）HU;CNR值分别为5.83±1.28、8.16±1.96和2.57±1.27。A,B两组门脉图像质量明显高于C组,有统计学差异（P〈0.01）。结论：双源双能CT在门脉成像中,单能量成像与常规成像方式相比,能够大大提高图像质量,可以应用于临床。

英文摘要：

Objective To explore the image quality of monochromatic imaging technique of second-generation dual-source computed tomography（CT） based on sonogram affirmed iterative reconstruction（SAFIRE） for abdominal vessel, portal vein. Methods Forty patients who underwent the upper- abdominal enhanced CT scan and dual- energy scan in the portal venous phase were selected. The dual- energy monochromatic software was applied to get the energy curve of contrast to noise ratio（CNR） of main portal vein, and obtain the monochromatic image with optimal monochromatic point. The obtained image data in the portal venous phase was retrospectively reconstructed by three different methods, optimal monochromatic ＋ filter back projection（FBP） in group A, optimal monochromatic ＋ iterative SAFIRE- 3 in group B, dualenergy tubes of 80 kV and 140 k V in group C. After scanning, automatically weighted portal venous images with tube voltage of 120 k V, the images of 120 k V＋ FBP, were taken as the routine group. The maximum intensity projection（MIP）,volume rendering（VR） and multiplanar reformation（MPR） of portal venous vascular reconstruction were conducted on a workstation. At the central layer of portal venous branch, the CT value of main portal vein and liver parenchyma, and the noise standard deviation were measured; the CNR was calculated. The portal venous images were evaluated by two experienced radiologists. Results The portal venous CT values were respectively（192.31±37.88） HU,（189.89±37.42） HU,（152.54±27.58） HU in group A, B, C. And the CNR were respectively 5.83±1.28, 8.16±1.96, 2.57±1.27 in group A, B, C.The image quality of group A and B were significantly higher than that of group C, with statistical differences（P〈0.01）.Conclusion Compared with the conventional imaging in the dual-source dual-energy CT for portal venous imaging, the monochromatic imaging, which can be used in the clinic, shows better image quality.