双能量融合技术对肝门静脉成像质量的研究

目的 探讨肝脏门静脉期双能量扫描线性融合图与非线性融合图在门静脉血管VRT图像中的应用价值.方法 60例临床确诊肝硬化门静脉高压胃底食管静脉曲张的患者,在肝脏CT增强门静脉期行双能量扫描(Sn140/80 kVp),利用80 kVp和140 kVp的2组数据,进行线性融合A组融合比率(M)=0.3, B组M=1.0;非线性融合C组融合中点(c)=150、融合宽度(w)=200, D组c=(CT肝门静脉+CT肝实质)/2、w=(CT肝门静脉-CT肝实质)/2,其中CT肝门静脉和CT肝实质值均在M=0.3时图像上测得.比较4组图像门静脉的CT值、 信噪比(SNR)、对比信噪比(CNR)、门静脉与肝实质CT值差,采用统计学one-way ANOVA检验客观分析.比较4组VRT图像采用统计学Kruskal-Wallis秩和检验,两两比较采用了Mann-Whitney U检验主观分析.结果 4组图像数据中,D组门静脉的SNR、CNR、门静脉与肝实质CT值差(14.36 HU±3.23 HU、9.78 HU±2.39 HU、107.66 HU±21.28 HU),与其他3组比较分值最高,统计学均有显著差异(F=34.94、68.10、162.43,P值均<0.01);4组VRT图像主观评分中,D组得分最高(平均分4.78±0.42),与其他3组比较统计学均有显著差异(P值均<0.01).结论 利用D组的非线性融合技术可提高门静脉成像质量,可在临床实践中推广使用.

Study on the imaging quality of hepatic portal venography by using dual-energy fusion technique

Objective To explore the value of linear blending and non-linear blending images of dual-energy CT in improving the image quality of portal venography.Methods 60 patients clinically confirmed as liver cirrhosis with portal hypertension and gastric fundus esophageal varices were enrolled in the study.The patients underwent dual-energy (Sn140/80 kVp) scans in the portal phase, and four groups with 80 kVp and 140 kVp were defined as group A (linear blending images with M=0.3), B (linear ones with M=1.0), C (non-linear ones with c=150 and w=200) and D [non-linear ones with c=(CThepatic portal+CThepatic parenchymal)/2 and w=(CThepatic portal-CThepatic parenchymal)/2, and the CThepatic portal and CThepatic parenchymal were measured on M=0.3 image].The in portal vein enhancements, image noise, signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR) and CT value difference between portal vein and liver parenchyma among four groups were compared by one-way ANOVA analysis of variance test.VRT imaging quality among four groups were assessed by Kruskal-Wallis test and Mann-Whitney U test.Results In four groups, the SNR and CNR of portal vein,and the CT value difference between portal vein and liver parenchyma(14.36 HU±3.23 HU,9.78 HU±2.39 HU,107.66 HU±21.28 HU) of group D were the highest (F=34.94,68.10 and 162.43,all P<0.01),and VRT image quality score of group D(4.78±0.42) was the best when compared to others (all P<0.01).Conclusion Non-linear blending technique of group D can improve the image quality of CT portography, which may be used in clinical practice.