MRI图像纹理分析在胰腺神经内分泌肿瘤病理分级中的应用研究

Application of texture analysis of MR imagings in grading of pancreatic neuroendocrine neoplasms

目的 :探讨MRI图像纹理分析在胰腺神经内分泌肿瘤分级中的应用价值。方法 :回顾性分析我院64例经手术或病理活检确诊为神经内分泌肿瘤患者的MRI图像,运用Ma Zda软件通过手动勾画感兴趣区(region of interest,ROI)的方式提取病变的纹理特征,通过特征选择方法选出最具鉴别胰腺神经内分泌肿瘤病理分级的纹理特征,方法包括Fisher系数(Fisher coefficient,Fisher)、分类错误概率联合平均相关系数(classification error probability combined average correlation coefficients,POE+ACC)、互信息(mutual information,MI)及上述3种方法的联合法(FPM)。用特征分类统计方法,判别3种病理分级(G1、G2、G3),结果以判错率形式表示。结果:特征选择方法中,3种方法联合法(FPM)选择的纹理特征鉴别3种病理分级的判错率最低,为9.38%(6/64);特征统计方法中,非线性判别分析(nonlinear discriminant analysis,NDA)区分G1、G2、G3 3种分级的判错率要低于原始数据分析(raw data analysis,RDA)、主成分分析(principal component analysis,PCA)、线性判别分析(linear discriminant analysis,LDA)。各序列中,表观弥散系数(apparent diffusion coefficient,ADC)图纹理分析判错率最低,但各序列之间的差异尚无统计学意义。结论:MRI图像纹理分析可作为胰腺神经内分泌肿瘤术前分级的辅助工具,采用Fisher系数、分类错误概率联合平均相关系数(POE+ACC)和互信息(MI)3种方法联合(FPM)的MRI图像纹理特征选择技术,结合非线性判别分析(NDA)方法 ,有较低的错判率。

Objective： To investigate the application of texture analysis derived from MR imaging in grading of pancreatic neuroendocrine neoplasms（PNENs）. Methods： MR imagings of 64 patients with pathologically confirmed PNENs admitted to Ruijin Hospital were enrolled. Texture features were extracted from manually drawn ROIs by using Ma Zda software, and were selected according to the pathological grade by the feature selection methods. Statistical methods including Fisher coefficient（Fisher）, classification error probability combined with average correlation coefficients（POE＋ACC）,mutual information（MI）, and combination of above three methods（FPM） were used to classify the pathological grading of PNENs. The results were shown by misclassification rate. Results： For feature selection methods, FPM had the lowest misclassification rate. Among the statistical methods, the misclassification of NDA was lower than those of RDA, PCA, and LDA. Among the MRI sequences, the ADC map obtained the lowest misclassification rate of 9.38%（6/64）, but there was no significant difference between sequences. Conclusions： Texture analysis of MR imaging can be used as an assistant tool for preoperative grading of pancreatic neuroendocrine neoplasms, and when it comes to statistical methods, FPM has the lowest misclassification rate.