基于PSNR和SSIM方法评估双能量CT肝脏虚拟平扫图像质量研究  

Assessment of the Image Quality of Virtual Non-Contrast Dualenergy CT Liver Scans Using Both PSNR and SSIM Methods

作　　者：李亚光[1] 李洁 薛廷玉 母建奎 王强[2] 郑立冬[1] 王勇 雷立存[1,3] LI Yaguang;LI Jie;XUE Tingyu;MU Jiankui;WANG Qiang;ZHENG Lidong;WANG Yong;LEI Licun(Department of Radiology and Nuclear Medicine,The FirstHospital of Hebei Medical University,Shijiazhuang 050000,China;Department of Thoracic Surgery,The FirstHospital of Hebei Medical University,Shijiazhuang 050000,China;College of Medical Imaging,Hebei Medical University,Shijiazhuang 050000,China)

机构地区：[1]河北医科大学第一医院放射与核医学科,石家庄050000 [2]河北医科大学第一医院胸外科,石家庄050000 [3]河北医科大学医学影像学院,石家庄050000

出　　处：《CT理论与应用研究(中英文)》2025年第1期51-57,共7页Computerized Tomography Theory and Applications

基　　金：河北省医学科学研究课题计划(基于深度学习的多模态影像技术对腹部实质脏器脂肪定量评估的应用研究(20231013))。

摘　　要：目的:采用峰值信噪比(PSNR)和结构相似性指数(SSIM)联合图像评价方法,探讨双能量CT的肝脏虚拟平扫(VNC)图像替代真实平扫(TNC)图像的可行性。方法:前瞻性分析33例肝脏CT平扫及Ⅲ期双能量增强扫描的影像学资料。经后处理获得动脉期VNC图像(VNCa)、静脉期VNC图像(VNCv)及延迟期VNC图像(VNCd)。将肝脏Ⅲ期VNC图像与TNC图像应用PSNR和SSIM方法进行整体及局部比对分析。测量肝脏及竖脊肌的CT值与噪声值(SD),计算信噪比(SNR)和对比噪声比(CNR),记录肝脏真实CT平扫及增强扫描的剂量长度乘积,比较Ⅲ期VNC与TNC图像质量的客观评价指标及辐射剂量,并绘制肝脏CT值、SNR和CNR的Bland-Altman散点图进行一致性分析。结果:整体图像评价Ⅲ期VNC与TNC图像比对的PSNR分别为(18.01±1.06)、(18.33±0.99)、(18.20±1.04),SSIM分别为(0.76±0.04)、(0.77±0.03)、(0.78±0.04);局部图像评价Ⅲ期VNC与TNC图像比对的PSNR为(29.90±2.50)、(30.97±2.34)、(30.61±2.76),SSIM为(0.75±0.04)、(0.77±0.03)、(0.77±0.04);Ⅲ期VNC与TNC图像整体及局部比对的PSNR、SSIM的差异没有统计学意义。Ⅲ期VNC的肝脏CT值高于TNC;Ⅲ期VNC的CNR及VNCv的SNR与TNC图像相比无统计学差异;肝脏CT值、SNR及CNR在Ⅲ期VNC与TNC图像之间均具有良好的一致性。去除真实平扫环节,采用VNC+Ⅲ期增强方案可降低约29.63%的辐射剂量。结论:双能量CT的肝脏VNC图像具有良好的图像质量,可以较真实地还原TNC图像,满足临床的诊断需求。The purpose of this study was to investigate the feasibility of replacing true non-contrast(TNC)dual-energy computed tomography(DECT)images with virtual non-contrast(VNC)DECT images by comparing their quality on the basis of both the peak signal-to-noise ratio(PSNR)and structural similarity index(SSIM).Methods:A prospective analysis was conducted on TNC and enhanced three-phase DECT images of the livers of 33 patients.Post-processing was used to obtain the arterial-phase(VNCa),venous-phase VNC(VNCv),and delayed-phase VNC(VNCd)images.Both the PSNR and SSIM methods were used to compare the overall and local TNC and three-phase VNC images.The CT numbers and noise values(standard deviation)of the liver and erector spinae muscle were measured,and the SNR and contrast-to-noise ratio(CNR)were calculated.The dose length product values of the TNC and enhanced three-phase VNC scans were recorded,and the objective evaluation indicators and radiation doses of the three-phase VNC and TNC images were compared.Bland-Altman scatter plots were drawn to analyze the consistency of the liver CT numbers,SNRs,and CNRs.Results:The overall comparison of the three-phase VNC and TNC images showed PSNR values of(18.01±1.06),(18.33±0.99),and(18.20±1.04)and SSIM values of(0.76±0.04),(0.77±0.03),and(0.78±0.04),with the differences being not statistically significant.The local comparison of these images showed PSNR values of(29.90±2.50),(30.97±2.34),and(30.61±2.76)and SSIM values of(0.75±0.04),(0.77±0.03),and(0.77±0.04),and the differences were also not statistically significant.The CT number of the liver in the three-phase VNC image was higher than that in the TNC image.The CNR of the three-phase VNC image and the SNR of the VNCv image were not statistically different from those of the TNC image,and the liver CT numbers,SNRs,and CNRs in the three-phase VNC and TNC images were highly consistent.Using the VNC+three-phase enhancement scheme can reduce the radiation dose by approximately 29.63%by removing the TNC part.Conclusion:The V

关 键 词：双能量CT 虚拟平扫 结构相似性指数 峰值信噪比 

分 类 号：R814[医药卫生—影像医学与核医学] TP391.41[医药卫生—放射医学]