ASIR-V算法降低COVID-19患者胸部CT累积有效剂量的可行性研究

Feasibility Study of Reducing the Cumulative Effective Dose in Chest CT Examinations for Patients with COVID-19 Using ASIR-V Algorithm

目的通过比较自适应统计迭代重建-V(adaptive statistical iterative reconstruction-V,ASIR-V)算法与常规滤波反投影(filtered back projection,FBP)重建算法之间的图像质量和辐射剂量,评价ASIR-V算法降低新型冠状病毒(coronavirus disease 2019,COVID-19)肺炎患者胸部电子计算机断层扫描(computed tomography,CT)的累积有效剂量(cumulative effective dose,CED)的可行性。方法53例在作者医院隔离治疗且应用256排CT配合ASIR-V算法完成多次胸部CT检查的COVID-19患者纳入实验组,50例应用64排CT配合FBP算法进行常规胸部CT筛查患者纳入对照组。比较两组间单次胸部CT扫描的平均辐射剂量和图像质量。记录实验组中每一位患者的胸部CT检查次数,并计算CED。结果实验组和对照组胸部CT图像的主观图像质量评分分别为(4.15±0.66)和(4.12±0.82),差异无统计学意义(U=-0.086,P=0.931)。实验组患者单次胸部CT扫描的辐射剂量参数均显著低于对照组(P=0.000)。其中,实验组和对照组的平均有效剂量(effective dose,ED)分别为(3.07±0.28)mSv和(5.36±0.75)mSv(t=-20.768,P=0.000),ASIR-V算法减少了43%的有效剂量。实验组患者解除隔离前的平均胸部CT检查次数和平均CED分别为(3.50±1.20)次和(10.83±3.85)mSv。结论相比FBP算法,ASIR-V算法通过减少单次CT扫描的辐射剂量,可以显著降低COVID-19患者由于反复CT复查所带来的高CED,并且不损害图像质量。

Objective To compare the image quality and radiation dose between the adaptive statistical iterative reconstruction-V(ASIR-V)algorithm and the conventional filtered back projection(FBP)reconstruction algorithm,and evaluate the feasibility of ASIR-V algorithm to reduce the cumulative effective dose(CED)of chest computed tomography(CT)in patients with coronavirus disease 2019(COVID-19).Methods Fifty-three COVID-19 patients who were isolated in authors′hospital and used256-row CT with ASIR-V algorithm to complete multiple chest CT examinations were included in the study group,and 50 patients with 64-row CT combined with FBP algorithm for routine chest CT screening were included in the control group.The mean radiation dose and the image quality of a single chest CT scan were compared between the two groups.The CT examination frequency and the CED of individual patients in the study group was recorded and calculated.Results The subjective image quality scores of the chest CT images for the study group and the control group were(4.15±0.66)and(4.12±0.82),respectively.There was not significantly different(U=-0.086,P=0.931).All radiation dose parameters of a single chest CT scan in the study group were significantly lower than those in the control group(P=0.000).The mean ED of the study group and the control group were(3.07±0.28)mSv and(5.36±0.75)mSv(t=-20.768,P=0.000).The usage of ASIR-V algorithm reduced the effective dose by 43%.The mean CT examination frequency and mean CED of each patient in the study group were(3.50±1.20)times and(10.83±3.85)mSv,respectively.Conclusion Compared with the FBP algorithm,ASIR-V algorithm has the potential to significantly reduce the high CED of COVID-19 patients due to recurrent CT reviews by reducing the radiation dose of a single CT scan without impairing the image quality.