DLIR算法结合前置ASIR-V技术在过重患者门静脉成像中的应用

Application of DLIR algorithm combined with pre-ASIR-V in CT portal venography for overweight patients

目的探讨深度学习图像重建(DLIR)算法结合前置自适应迭代重建-V(ASIR-V)技术在过重患者门静脉成像(CTPV)中的应用价值。方法本前瞻性研究对象为2021年6月至9月在中山大学附属第三医院接受腹部增强CTPV检查的50例患者。其中男31例,女19例;年龄19~74岁,中位年龄56岁;BMI>25 kg/m^(2)。患者均签署患者知情同意书,符合医学伦理学规定。比较前置50%ASIR-V技术(开启)和前置0%ASIR-V(关闭)时有效辐射剂量(ED)。采用60%ASIR-V、80%ASIR-V、DLIR-M(中等级别)和DLIR-H(高等级别)4种算法分别对患者门静脉期数据进行薄层重建。图像质量的客观评价指标包括门静脉CT值的标准差(SD)值、信噪比(SNR)和对比噪声比(CNR),主观评价由两名放射科医师对重建图像质量进行双盲法评分。前置ASIR-V开启前后ED比较采用t检验。不同算法的SD、SNR、CNR等客观评价指标比较采用单因素方差分析;主观图像质量评分比较采用Kruskal-Wallis检验,采用Kappa检验分析两名放射科医师的主观图像质量评分的一致性。结果前置ASIR-V关闭和开启后平均ED分别为(11.1±1.4)、(7.6±1.1)mSv,ED降低32%(t=14.01,P<0.05)。对于门静脉主干,DLIR-H组SD最小,SNR和CNR最大(P<0.05)。对于门静脉分支,80%ASIR-V组SD最小,SNR最大;DLIR-H组CNR最大(P<0.05)。在所有算法重建的图像中,DLIR-H组门静脉重建图像质量的主观评分最高(P<0.05)。两名放射科医师对60%ASIR-V、80%ASIR-V、DLIR-M和DLIR-H算法的门静脉重建图像质量的主观评分一致性较好(κ=0.810,0.556,0.705,0.676;P<0.05);对门静脉整体和分支图像质量的主观评分一致性亦较好(κ=0.661,0.959;P<0.05)。结论在过重患者门静脉造影中,前置ASIR-V技术可明显降低ED;DLIR算法可显著降低噪声,不改变其纹理,相比ASIR-V算法可获得更好的门静脉期图像,其中高级别DLIR算法重建图像最佳。

Objective To evaluate the application value of deep learning image reconstruction(DLIR)algorithm combined with pre-adaptive statistical iterative reconstruction-V(ASIR-V)in CT portal venography(CTPV)for overweight patients.Methods 50 patients receiving abdominal enhanced CTPV in the Third Affiliated Hospital of Sun Yat-sen University from June to September 2021 were enrolled in this prospective study.Among them,31 patients were male and 19 female,aged from 19 to 74 years,with a median age of 56 years and BMI>25 kg/m^(2).The informed consents of all patients were obtained and the local ethical committee approval was received.The effective dose(ED)was compared between 50%pre-ASIR-V(turned on)and 0%pre-ASIR-V(turned off).The data of portal venous phase were thin-slice reconstructed with 4 algorithms 60%ASIR-V,80%ASIR-V,DLIR-M(middle level)and DLIR-H(high level),respectively.The objective evaluation parameters of image quality included standard deviation(SD)of CT value of portal vein,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR).The subjective assessment of reconstructed images was performed with double-blind method by two radiologists.The ED before and after turning on pre-ASIR-V was statistically compared by t test.The SD,SNR,CNR and other objective evaluation parameters of image quality among different algorithms were compared by one-way ANOVA.The subjective scores were compared by Kruskal-Wallis test.The consistency of subjective scores of image quality between two radiologists was analyzed by Kappa test.Results The average ED was(11.1±1.4)and(7.6±1.1)mSv before and after turning on pre-ASIR-V,respectively,which was decreased by 32%(t=14.01,P<0.05).For the main portal vein,the SD was the lowest,the SNR and CNR were the highest in DLIR-H group(P<0.05).For the portal vein branches,the SD was the lowest and the SNR was the highest in 80%ASIR-V group,and the CNR was the highest in DLIR-H group(P<0.05).Among all the images reconstructed by different algorithms,the subjective score was the highest in DLIR-H group(P<0.05).The consistency of scores of two radiologists was comparatively high for the portal vein images reconstructed with 60%ASIR-V,80%ASIR-V,DLIR-M and DLIR-H algorithms(κ=0.810,0.556,0.705,0.676;P<0.05).Comparatively high consistency was also observed in the subjective scores for the images of portal vein system and portal vein branches(κ=0.661,0.959;P<0.5).Conclusions In the CTPV for overweight patients,pre-ASIR-V can significantly reduce the ED.DLIR algorithm can significantly reduce the noise without changing the texture.Compared with ASIR-V algorithm,DLIR algorithm can obtain better portal vein phase images,especially the DLIR-H algorithm.