双源CT双能量扫描在肝脏成像中的应用研究

Evaluation of Liver Imaging by Dual-source Dual-energy CT

目的:比较双源CT双能量扫描与常规扫描在肝脏成像中的图像质量及辐射剂量。方法:随机选择腹部常规平扫、增强扫描患者34例,通过伦理委员会审查征得病人知情同意后,行双源CT平扫及增强扫描,增强扫描门脉期选择双能量扫描方案,记录扫描中患者所接受的辐射剂量。扫描结束后,应用后处理软件重建出肝脏虚拟平扫图像,将肝脏常规平扫与虚拟平扫的图像质量、辐射剂量、图像噪声(SD)、信噪比(Mean/SD)进行对比分析。图像质量等级评价结果采用秩和检验;SD与Mean/SD值、辐射剂量评价若满足正态、方差齐采用t检验,若不满足则采用秩和检验。结果:肝脏常规平扫与虚拟平扫辐射剂量无统计学差异(P>0.05)。常规平扫与虚拟平扫图像质量等级评价结果、噪声(SD)、信噪比(Mean/SD)有统计学差异(P﹤0.05)。常规平扫图像质量优于虚拟平扫,虚拟平扫的噪声低于常规平扫、信噪比高于常规平扫。结论:肝脏双能量虚拟平扫与常规平扫相比,图像噪声低、信噪比高,在肝脏检查中可替代常规平扫,减低患者的扫描时间及辐射剂量。

Purpose：To compare the image quality and radiation dosage of virtual non-contrast for liver imaging with second-generation,dual-source CT in comparison with routine non-contrast images.Methods：Institutional review board approval was obtained.Thirty-four patients underwent liver contrast-enhanced dual-energy CT scan that included routine non-contrast images acquired in single-energy mode,corticomedullary phase images acquired in dual-energy mode,and nephrographic phase images acquired in singleenergy mode.The radiation dosages in patients received by scanning were recorded.The liver virtual noncontrast images were reconstructed after scanning.The acceptance level and image quality of virtual and routine non-contrast images were evaluated.And the image quality,radiation dose,and image noise （SD）,signal to noise ratio （Mean/SD） of them were analyzed.The image quality evaluation results were analyzed with rank sum test.The differences of radiation dosage,SD and Mean/SD value between virtual and routine non-contrast images were analyzed with t-test or rank sum test.Results：The differences of image quality level,SD and Mean/SD between liver routine non-contrast and virtual non-contrast images were with statistical significant （P＜0.05）.The radiation dosage between routine non-contrast and virtual non-contrast images was with no significant difference （P＞0.05）.Conclusion：Dual-source dual-energy CT is a reliable imaging technique in the evaluation of liver.Routine non-contrast images can be replaced by virtual noncontrast images with considerable radiation dose reduction.