应用高分辨率CT局部放大重建提高肺部小结节结构精准诊断的价值

目的探讨局部放大重建在肺部小结节结构精准诊断上的价值。方法使用常规胸部CT条件扫描质控模型Catphan500体模,关闭自动辐射剂量调节技术。根据扫描和重建方式不同分为改变扫描FOV组与改变重建FOV组,改变扫描FOV组控制扫描FOV分别为500 mm×500 mm、400 mm×400 mm、300 mm×300 mm、200 mm×200 mm、100 mm×100 mm,改变重建FOV组控制扫描FOV为500 mm×500 mm,分别在扫描FOV为500 mm×500 mm的条件下使用原始数据重建FOV为400 mm×400 mm、300 mm×300 mm、200 mm×200 mm、100 mm×100 mm的图像,控制其他条件均一致。观察Catphan 500体模高对比度分辨率模块,比较两组图像在不同扫描FOV或不同重建FOV下的线对数。回顾性分析2018年2月至3月浙江大学医学院附属第二医院肺部小结节患者35例,均行胸部高分辨率CT平扫,使用原始数据重建图像,常规重建组的重建FOV为320 mm×320 mm,局部放大重建组的重建FOV为100 mm×100 mm,分别对图像质量进行主观评价并采用秩和检验进行比较。结果使用质控模型Catphan 500体模扫描时,随着扫描FOV或重建FOV的逐渐缩小,改变扫描FOV组与改变重建FOV组高对比度分辨率模块图像能显示的线对数逐渐增大,且保持一致。常规重建组的图像质量评分为(3.86±0.50)分,局部放大重建组(4.77±0.35)分,局部放大重建组评分高于常规重建组,差异有统计学意义(Z=-5.763,P<0.05)。结论高分辨CT局部放大重建图像能取得与局部放大扫描一致的图像质量,局部放大重建图像质量优于单纯图像放大。

Application of high-resolution CT local augmentation reconstruction to improve the accurate diagnosis of small pulmonary nodule structure

Objective To explore the accurate display method of the local structure of small CT nodules in lung.Methods Close the automatic radiation dose adjustment technique.Keep the thickness of the phantom was 2 mm,the interval between the phantom layers was 2 mm,the pitch was 1,and the reconstructed convoluted nucleus was B80s.Group A controlled the scanning matrix FOV to be 500 mm×500 mm,400 mm×400 mm,300 mm×300 mm,200 mm×200 mm and 100 mm×100 mm,while group B controlled the scanning matrix FOV to be 500 mm×500 mm.Use these parameters to scan the catphan 500 phantom,a routine chest CT conditioned scanning quality control model.The original data raw data were used to reconstruct the FOV to be 400 mm×400 mm,300 mm×300 mm,200 mm×200 mm and 100 mm×100 mm under the scanning FOV to be 500 mm×500 mm.All other conditions are consistent.Observe the high contrast resolution module of Catphan 500 phantom,and compare the line logarithms of two groups of images under different scanning FOV or different reconstruction FOV.Thirty-five patients with small pulmonary nodules from February 2018 to March 2018 of the Second Affiliated Hospital of Zhejiang University Medical College were retrospectively collected.The raw data were used to reconstruct the images.The FOV was 320 mm×320 mm in the conventional reconstruction group and 100 mm×100 mm in the local magnification reconstruction group.The subjective score data of the two groups were compared by using rank-sum test.Results When catphan 500 phantom was used,the number of lines in group A and group B increased gradually with the decreasing of FOV.The subjective score of local magnification reconstruction group(4.77±0.35)was higher than that of conventional reconstruction group(3.86±0.50)and the difference was statistically significant(Z=-5.763,P<0.05).Conclusion Local magnification and reconstruction of high-resolution CT images can achieve the same image quality as local magnification,local magnification and reconstruction of image quality is significantly better than simple image magnification.