基于双层探测器的光谱CT虚拟单能量图像优化门静脉血管图像质量的研究

Study of Virtual Monoenergetic Image Based on Dual-Layer Spectral Detector CT for Optimizing the Image Quality of Portal Vein

目的探讨双层探测器光谱CT(SDCT)虚拟单能量图像(VMI)对优化门静脉血管图像质量的价值。方法回顾性分析2019年5—10月在天津医科大学宝坻临床学院行腹部SDCT平扫及增强扫描的44例患者的影像资料,重建不同VMI(40、50、60、70 keV)组和常规混合能量(QC)组门静脉图像,比较各组门静脉CT值、平均图像噪声值(IN)、信噪比(SNR)、对比噪声比(CNR)及图像质量主观评分,并进行统计学分析。结果各组间的门静脉CT值、SNR、CNR及图像质量主观评分比较,差异均有统计学意义(P<0.001);40 keV组门静脉CT值、SNR、CNR及图像质量主观评分均高于其余能级组和QC组,差异有统计学意义(P<0.05或0.01);各组间的IN比较,差异无统计学意义(P=0.108)。结论SDCT的VMI能够提高门静脉的图像质量且以40 keV时最佳。

Objective The value of the virtual monoenergetic image(VMI)based on dual-layer spectral detector CT(SDCT)for optimizing the image quality of portal vein was investigated.Methods The imaging data of 44 patients received abdominal SDCT imaging including plain and enhanced scan from May to October in 2019 in Baodi Clinical College of Tianjin Medical University were retrospectively analyzed.Portal vein images were reconstructed in different VMI(40、50、60、70 keV)groups and mixed energy(quality check,QC)group,respectively.Parameters of portal vein including CT value,image noise(IN),signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)and subjective image scores were compared and analyzed statistically.Results When CT values,SNR,CNR and subjective image scores of portal vein among all groups were compared,the differences were all statistically significant(P<0.001);The CT values,SNR,CNR and subjective image scores of portal vein in 40 keV group were were higher than the other energy level groups and QC group,and the differences were all statistically significant(P<0.05 or 0.01);When the IN were compared among all groups,the difference was not statistically significant(P=0.108).Conclusion The image quality of portal vein could be enhanced by VMI with SDCT,especially in 40 keV.