能谱CT最佳单能量成像技术及最佳迭代算法技术在肋间后动脉显像的应用价值

The application value of the best single energy imaging technology and the best iterative algorithm technology of energy spectrum CT in the imaging of the posterior intercostal artery

目的探讨能谱CT最佳单能量成像技术及最佳迭代算法技术,在提高肋间后动脉显像的应用价值。方法选取2017年4月~2018年1月能谱CT胸部增强扫描患者30例。采用能谱扫描模式扫描完成后根据GSI Viewer软件计算出的肋间后动脉单能量图像的最佳keV值,采用文献中最佳ASIR权重为60%。然后分别重建:70 keV+FBP,70 keV+最佳ASIR权重,最佳单能量+FBP,最佳ASIR权重+最佳单能量的4组图像。分别测量动脉期各组图像中肋间后动脉以及同层面背部肌肉和腋下脂肪的CT值和SD值,计算肋间后动脉的对比噪声比(CNR)、信噪比(SNR),并比较分析。由两位副高级及以上职称影像科医师根据图像噪声、血管边缘清晰度及诊断信心对肋间后动脉血管成像进行主观评分。结果肋间后动脉最佳单能量范围为60~71 keV,平均(63.33±2.66)keV。70 keV+FBP组、70 keV+最佳ASIR权重、最佳单能量+FBP、最佳单能量+最佳ASIR权重4组图像平均SNR分别为17.64±8.68,23.03±11.69,19.34±8.83,25.89±12.37。70 keV+FBP组、70 keV+最佳ASIR权重、最佳单能量+FBP、最佳单能量+最佳ASIR权重4组图像平均CNR分别为14.87±7.36,19.26±9.90,16.81±8.13,22.14±10.97。结论能谱CT扫描最佳权重下与最佳单能量联合应用的SNR及CNR最高,可进一步提高肋间后动脉血管成像的图像质量。

Objective To explore the best single energy imaging technology and the best iterative algorithm technology of energy spectrum CT,so as to improve the application value of posterior intercostal artery imaging.Methods From April 2017 to January 2018,30 patients with enhanced energy spectrum CT were prospectively collected.The best keV value of the single energy image of the intercostal artery calculated by GSI viewer software after the scanning was completed was used in the energy spectrum scanning mode.The best ASIR weight in literature was 60%12-14.Then,four groups of images were reconstructed respectively 70 keV+FBP,70 keV+best ASIR weight,best single energy+FBP,best ASIR weight+best single energy.The CT and SD values of the posterior intercostal artery,the same layer of back muscle and axillary fat were measured in each group during the aortic phase.The CNR and SNR of the posterior intercostal artery were calculated and compared.According to the image noise,the definition of blood vessel edge and the confidence of diagnosis,two radiologists with associate senior and above professional titles scored the image of posterior intercostal artery.Results The best single energy range of posterior intercostal artery was 60~71 keV,with an average of 63.33±2.66 keV.The average SNR of the four groups was 17.64±8.68,23.03±11.69,19.34±8.83,25.89±12.37,respectively.The average CNR of the four groups was 14.87±7.36,19.26±9.90,16.81±8.13,22.14±10.97,respectively.Conclusion Under the best weight of energy spectrum CT scan and the best single energy combination,SNR and CNR are the highest,which can further improve the image quality of posterior intercostal artery angiography.