目的：探讨能谱CT技术对提高肝硬化患者门静脉成像质量的应用价值。方法：对临床明确有肝硬化病史的42例患者行上腹部CT增强扫描，平扫、动脉期采用常规螺旋扫描，门静脉期使用能谱扫描模式获得门静脉期最佳对比信噪比（CNR）单能图像和传统混合能量图像（QC图像），并行门静脉容积再现（VR）和最大密度投影（MIP）重组。测量两组图像中门静脉和肝实质的CT值、图像噪声，用肝实质作为对照测量门脉主干的CNR，并由两名具有10年以上腹部影像诊断经验的医师在盲法条件下对2组重建图像进行主观图像质量评分。两组间比较采用两独立样本t检验，两名医师对重建图像质量一致性评估采用Kappa检验。结果：门静脉最佳CNR单能图像能量水平集中在50~53 keV左右。最佳CNR单能图像上门静脉和肝实质的CT值、图像噪声和门静脉-肝实质的CNR（分别为（300.82±33.07） HU，（147.53±22.65） HU，26.48±3.87，5.87±1.35）均高于QC图像（分别为（150.05±27.36） HU，（98.96±16.33） HU，16.78±3.10，3.06±0.99），两者间差异有统计学意义（P<0.01）。两名医师对最佳CNR单能重建图像质量评价一致性（Kappa值为0.759）高于QC重建图像（Kappa值为0.521）；两组图像质量评分分别为（4.17±0.72）分和（3.06±0.55）分，差异有统计学意义（P<0.01）。结论：能谱CT最佳CNR单能量图像能明显提高肝硬化门静脉与肝实质的CNR，使门静脉及其分支的图像质量显著提高。

Objective: To investigate the effect of spectral CT technology for improving imaging quality of portal venography in cirrhosis patients. Methods: 42 patients with cirrhosis underwent enhanced CT scans spectral CT mode in the portal phase and conventional helical mode in other phase. The best contrast-to-noise ratio(CNR) for main portal veins, as well as the conventional polychromatic images were obtained in the portal phase, and volume rendering and maximum intensity projection were created to show the portal veins. CT value of the main portal vein, liver parenchyma and image noise were measured. Overall imaging quality were assessed by two radiologists with more than 10 years’ experience of abdominal imaging diagnosis. Comparison between the two groups by using independent-samples t test. Inter-observer agreement in subjective image quality was assessed by Kappa statistics. Results: The monochromatic images at 50~53 keV were found to have the best CNR for portal veins. CT value of the main portal vein and liver parenchyma, the image noise and the CNR of optimal monchromatic images were statistically significantly higher than that of polychromatic images, respectively(P<0.01). In the comparison of image quality, the optimal monochromatic reconstructed images(Kappa value=0.759) were higher than polychromatic reconstructed images(Kappa value=0.521). The image quality scores of two groups were 4.17±0.72 and 3.06±0.55. There were significant differences between the image quality scores of two groups(P<0.01). Conclusion: Monochromatic images of spectral CT could improve CNR for display portal veins and improve the image quality.