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 Dual-energy CT Liver Scans Using Both PSNR and SSIM Methods
李亚光 1李洁 2薛廷玉 1母建奎 3王强 3郑立冬 1王勇 1雷立存4
作者信息
- 1. 河北医科大学第一医院放射与核医学科,石家庄 050000
- 2. 河北医科大学医学影像学院,石家庄 050000
- 3. 河北医科大学第一医院胸外科,石家庄 050000
- 4. 河北医科大学第一医院放射与核医学科,石家庄 050000;河北医科大学医学影像学院,石家庄 050000
- 折叠
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.
Abstract
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 VNC DECT image of the liver is of good quality and can accurately reproduce the TNC image,meeting clinical diagnostic needs.
关键词
双能量CT/虚拟平扫/结构相似性指数/峰值信噪比Key words
dual energy computed tomography/virtual non-contrast scan/structural similarity index/peak signal to noise ratio引用本文复制引用
出版年
2025
国家科技期刊平台
NSTL
万方数据