不同螺距联合ASIR重建技术在COVID-19胸部低剂量CT扫描中的应用研究

The Study of Application of Different Pitch Combined with ASIR in Low-dose Chest CT Screening on COVID-19

目的:探讨2019冠状病毒病(COVID-19)患者使用大螺距联合自适应统计迭代重建技术行低剂量扫描的可行性,比较辐射剂量及图像质量的差异。方法:收集我院确诊为COVID-19的病例共91例作为低剂量组,同时选取同期于我院行新冠肺炎筛查的91例未确诊为COVID-19的患者作为常规剂量组。低剂量组使用大螺距扫描联合自适应统计迭代重建算法(ASIR);常规剂量组使用常规螺距扫描,使用滤波反投影法(FBP)进行重建。记录两组辐射剂量并对两组病例的图像质量进行主观及客观评分,比较各组图像质量与辐射剂量的差别。结果:低剂量及常规剂量两种方法的辐射剂量有统计学差异低剂量组辐射剂量明显低于常规剂量组(ED降低了52%);低剂量组与常规剂量组的图像质量评分无统计学差异;低剂量组与常规剂量组的客观评价无统计学差异。结论:应用大螺距联合ASIR重建技术对COVID-19患者行低剂量扫描可以明显降低辐射剂量而图像质量无明显下降。

Objective:To explore the feasibility of low-dose scanning for COVID-19 patients by using the method of high-pitch combined with ASIR,and compare the diffrence of radiation dose and image quality.Methods:91 patients diagnosed with COVID-19 in our hospital were collected as the low-dose group while 91 cases of undiagnosed COVID-19 patients who were screened for COVID-19 in our hospital during the same period were selected as the conventional dose group.High-pitch combined with ASIR was performed on the low-dose group while conventional dose group was scanned by common pitch and reconstructed by FBP.In order to compare the differnce of the image quality and radiation dose between the two groups,we recorded the radiation dose and performed subjective and objective evaluation of image quality of the two groups.Results:There was statistical differences in radiation dose between the two groups,and the radiation dose of the low-dose group was significantly lower than that of the conventional dose group(the ED was reduced by about 52%).There was no statistical difference in the image quality scores between the two groups;There was no statistical difference in the objective evaluation of images between the two groups.Conclusion:Low dose scanning with high-pitch combined with ASIR for COVID-19 patients can evidently reduce the radiation dose without significant decrease in image quality.