双能CT虚拟单能级成像显示胰周血管:与线性融合图像对照研究  

Dual⁃Energy CT with Virtual Monoenergetic Images in Demonstration of Peripancreatic Vessels:Comparison with Polyenergetic Images

作　　者：梁洪伟 周旸[1] 张志伟[1] 杜思霖[1] 郑桥 李信友[1] 吕发金[1] 李咏梅[1] LIANG Hongwei;ZHOU Yang;ZHANG Zhiwei;DU Silin;ZHENG Qiao;LI Xinyou;LÜFajin;LI Yongmei(Department of Radiology,The First Affiliated Hospital of Chongqing Medical University)

机构地区：[1]重庆医科大学附属第一医院放射科

出　　处：《中国医学计算机成像杂志》2022年第1期56-62,共7页Chinese Computed Medical Imaging

基　　金：重庆市卫健委医学科研重点课题(2016ZDXM002)。

摘　　要：目的:探讨和线性融合图像相比,双能CT虚拟单能级成像提高胰周血管显示的能力。方法:对45例非胰腺病变患者行双能CT增强扫描(100 kV/Sn150 kV),并对动脉及门脉期图像进行单能级重建(40~100 keV,间隔10 keV)及权重因子M0.6的线性融合重建。测量并比较8组图像上腹腔干、肝总动脉、脾动脉、肠系膜上动脉、胃十二指肠动脉、门静脉、肠系膜上静脉和胰腺实质的CT值、信噪比(SNR)、对比噪声比(CNR)、信号强度比(SIR)及图像噪声,并以5分法对图像质量和胰周血管显影的能力进行主观评价。结果:各血管及胰腺实质的SNR、CNR及SIR随着能级的降低而逐渐增高,并在40 keV单能级时达到最大值;图像噪声在40~50 keV单能级图像上明显高于其他单能级和线性融合图像(P<0.001),线性融合图像噪声和60 keV单能级图像相当(P=0.311);40~60 keV单能级图像胰周血管评分明显高于其他单能级及线性融合图像(P<0.001),50~60 keV时图像质量评分均高于其他单能级及线性融合图像(P<0.05)。结论:与线性融合图像相比,双能CT低keV单能级图像能获得更好的图像对比度及显示胰周血管,并在40 keV单能级重建时显示血管效果最佳,50~60 keV时显示图像质量最佳。Objective:To investigate the performance of virtual monoenergetic images of dual-energy CT in demonstration of peripancreatic vessels compared with conventional polyenergetic images.Methods:Forty-five patients with non-pancreatic lesions underwent contrast enhanced dual-energy CT scan using tube voltage of 100 kV and Sn150 kV.Then the arterial phase and portal phase images were postprocessed using virtual monoenergetic reconstruction and linear blending technique(M=0.6).One standard polyenergetic image(PEI)and seven virtual monoenergetic images(MEI[+])ranging from 40 to 100 keV at an interval of 10 keV were generated.The CT values,signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR),signal-to-intensity ratio(SIR)of pancreas parenchyma and seven peripancreatic vessels(celiac axis,common hepatic artery,splenic artery,superior mesenteric artery,gastroduodenal artery,portal vein and superior mesenteric vein)and image noise on the 8 sets of images were measured and compared.For subjective quality assessment,two readers independently assessed the images using a 5-point classification scale.Results:The SNR,CNR and SIR of each vessel and pancreatic parenchyma increased gradually with decreasing energy,and were maximized at 40 keV MEI(+);image noise for 40-50 keV MEI(+)were significantly higher than that for other MEI(+)and PEI(P<0.001),and the noise of 60 keV MEI(+)was equivalent to PEI(P=0.311);the peripancreatic vessels scores of 40-60 keV MEI(+)were significantly higher than that of other MEI(+)and PEI(P<0.001),and the subjective image qualities scores of 50-60 keV MEI(+)were higher than that of other MEI(+)and PEI(P<0.05).Conclusion:Compared with the PEI,the dual energy CT low keV MEI(+)can obtain better image contrast and improve visualization of peripancreatic vessels.The 40 keV MEI(+)can provide best visualization of peripancreatic vessels,and the 50-60 keV MEI(+)can provide best subjective and objective image quality.

关 键 词：胰腺 胰周血管 双能CT 虚拟单能级成像 

分 类 号：R817.4[医药卫生—影像医学与核医学]