双能量CT虚拟单能量重建技术显示肝癌TACE术后碘油沉积的价值

Dual-energy CT monoenergetic reconstruction technique for demonstrating lipiodol deposition after TACE in HCC patients

目的：探讨双能量CT虚拟单能量重建技术对肝癌经导管动脉化疗栓塞（TACE）术后碘油沉积的临床诊断价值。方法：对11例肝癌TACE术后患者进行双能量腹部CT平扫。在100kVp、140kVp、线性融合图像（M=0.5）和以9组虚拟单能量（40、60、80、100、120、140、160、180和190keV）图像上,在碘油沉积最显著的层面,测量伪影区及正常肝实质区的CT值,计算图像噪声（SD）和伪影指数（AI）。对伪影大小、图像噪声、碘油形态及综合图像质量分别进行主观评分。结果：客观评估：80keV图像的AI值最小;线性融合图像、80keV图像的噪声最小。主观评估：在140kVp、100~190keV图像上伪影较少;线性融合图像和80keV图像的噪声评分最小;碘油形态以140kVp、线性融合图像、80及100keV图像上显示较为清晰。整体综合评分以线性融合图像和80keV图像最高。结论：双能量CT虚拟单能量重建技术在肝癌TACE术后碘油沉积的显示中,可以改善图像质量,以80keV的虚拟单能量重建图像为最佳。

Objective：To explore the value of monoenergetic reconstruction technique of dual energy CT for demonstration of lipiodol deposition in HCC patients after transcatheter arterial chemoembolization（TACE）.Methods：Totally 11 patients clinically diagnosed as hepatic cancer and undergone TACE were enrolled in this retrospective study.Dual-energy scan was used in the non-contrast CT examination.In each patient,twelve groups of images were acquired,including 100and140 kVp images,linear blending images（M=0.5）and 9groups of monoenergetic images（40,60,80,100,120,140,160,180,and 190keV）.In each group three images of the same slices with the most severe hard-beam artifact were selected,on which ROIs were drawn in normal area of liver and areas with most severe artifact and CT values were measured,and then image noise and artifact index（AI）was calculated.For subjective evaluation of image quality,hard-beam artifact,image noise,contour of lipiodol deposition and comprehensive image quality were scored by two experienced radiologists.Results：For objective analysis,AI value was the least in 80 keV images,and image noise was the least in 80 keV images and linear blending images.For subjective analysis,the scores of image artifact on 140 kVp and 100~190keV images were lower than that of the other groups.The score of image noise was the least on linear blending image and 80 keV image.The contour of lipiodol was much clear on linear blending image,140 kVp,80and 100 keV images.For overall image quality,linear blending images and 80 keV images were the best.Conclusion：80keV images of monoenergetic reconstruction in dual energy CT should be used to demonstrate lipiodol deposition in HCC patients after TACE procedure.