虚拟滤线栅对胸部X线摄影图像质量影响的研究  

Study on the effect of virtual grid on chest X-ray image quality

作　　者：康天良[1] 刘云福[1] 张永县[1] 郭森林[1] 马文涛[1] 牛延涛[1] Kang Tianliang;Liu Yunfu;Zhang Yongxian;Guo Senlin;Ma Wentao;Niu Yantao(Department of Radiology,Beijing Tongren Hospital,Capital Medical University,Beijing 100730,China)

机构地区：[1]首都医科大学附属北京同仁医院放射科,北京100730

出　　处：《中华放射学杂志》2023年第5期547-552,共6页Chinese Journal of Radiology

摘　　要：目的探讨胸部X线摄影中不同管电压时虚拟滤线栅对图像质量的影响。方法根据临床实践中常用胸部X线摄影条件,确定相应厚度的有机玻璃(20 cm,含CDRAD模体)作为被照体。选择固定管电流量4 mAs,管电压60~125 kV,分别对被照体进行3种方式成像:无滤线栅、虚拟滤线栅和物理滤线栅。对获得的图像分别进行常用物理参数[对比噪声比(CNR)、相对噪声(σ)、对比度(C)、信噪比(SNR)]、纹理分析(角二阶矩、纹理对比度、纹理相关性、逆差矩、熵)和对比度细节模体评分[影像质量因子(IQ_(Finv))]的评价。对常用物理评价参数采用双因素方差分析,并进一步作两两比较。同时使用胸部拟人模体成像进行虚拟滤线栅处理前后图像纹理对比分析。结果3种滤线栅方式的图像质量差别有统计学意义(P<0.05),其中物理滤线栅图像质量最佳。管电压对各评价指标均有影响(P<0.05)。管电压与CNR、SNR、角二阶矩、逆差矩和IQ_(Finv)呈正相关(P<0.05),与σ、C、纹理对比度和熵呈负相关(P<0.05),而纹理相关性与管电压相关性无统计学意义(P>0.05)。胸部拟人模体图像在虚拟滤线栅处理前后纹理指标(角二阶矩、纹理对比度、纹理相关性、逆差矩、熵)均有统计学意义(P<0.05)。结论虚拟滤线栅能够提高胸部X线摄影的图像质量,图像纹理分析方法可作为图像质量评价参数的有益补充。Objective To explore the image quality and its evaluation method using virtual grid under different tube voltages in the clinical chest X-ray exam.Methods According to the conditions of chest X-ray photography commonly used in clinical practice,the corresponding thickness of plexiglass(20 cm,including CDRAD phantom)was determined as the experimental object.With a fixed tube loading of 4 mAs and the tube voltage from 60 to 125 kV,the experimental object was imaged in three ways:physical grid,none grid and virtual grid.The common physical parameters(CNR,σ,C,SNR),texture analysis(Angular second moment,texture Contrast,Correlation,Inverse difference moment,Entropy)and CDRAD phantom score(IQ_(Finv))were evaluated.Two-way ANOVA test was used for each group of common physical parameters,and further pairwise comparisons were made.At the same time,applying virtual grids on the obtained images with chest anthropomorphic model and texture indexing the images with and without virtual grids,then rank sum test of paired sample can be conducted.Results There were differences in image quality among the three groups of grid mode(P<0.05),and the physical grid delivered the best image quality.The tube voltage had an impact on all image quality evaluation indexes(P<0.05).The tube voltage was positively correlated with CNR,SNR,angular second moment,inverse difference moment and IQ_(Finv)(P<0.05),and negatively correlated withσ,C,texture contrast and entropy(P<0.05).There was no significant correlation between the tube voltage and Correlation(P>0.05).The chest anthropomorphic model images were used to evaluate the virtual grids,and the texture indexes(Angle second moment,Contrast,Correlation,Inverse difference moment,Entropy)were statistically significant(P<0.05).Conclusions The virtual grid can improve the image quality of chest X-ray photography,and the image texture analysis method can be a useful supplement to the image quality evaluation parameters.

关 键 词：放射摄影术 胸部 滤线栅 虚拟滤线栅 图像质量 纹理分析 

分 类 号：R816.4[医药卫生—放射医学]