DCE-MRI直方图分析在脑胶质瘤分级中的应用

摘要

目的:探索动态增强磁共振成像(DCE MRI)结合以整个肿瘤体积为基础的直方图(Histogram)分析方法在脑胶质瘤分级中的应用价值.方法:回顾性分析31例经过DCE-MRI检查的胶质瘤患者,其中包括8例低级别胶质瘤(LGG)和23例高级别胶质瘤(HGG).应用血流动力学模型计算出各个病例的渗透参数,包括容积转运常数(Ktrans)、回流速率常数(Kep)、血管外细胞外容积比(Ve)和血浆容积(Vp);选取肿瘤实质区作为感兴趣区(ROI),并计算出各渗透参数的直方图参数,包括平均值、标准差、峰度、偏度及第90百分位数.不同级别胶质瘤的Ktrans、Kep、Ve和Vp直方图参数值的比较采用Mann-Whitney U检验,采用ROC分析直方图各参数值鉴别HGG和LGG的诊断效能,应用组内相关系数(ICC)分析数据测量的可重复性.结果:Ktrans值的平均值、标准差、峰度、偏度及第90百分位数在鉴别LGG与HGG中的差异均具有统计学意义(P＜0.05).ROC分析显示以上各值在鉴别高、低级别胶质瘤中均有较好的诊断效能,其中Ktrans值的偏度诊断准确性最高.各组ICC值显示出较好的可重复性.结论:DCE MRI成像结合全肿瘤直方图分析方法在胶质瘤的分级中具有重要的应用价值.%Purpose:To explore the value of dynamic contrast enhanced MRI (DCE-MRI) with histogram analysis in the grading of brain gliomas.Methods:Thirty-one patients with gliomas who were undergone DCE-MRI before surgery were analyzed retrospectively.Of the 31 patients,8 were with low grade gliomas (LGG) and 23 were with high grade gliomas (HGG).The commonly used pharmacokinetic parameters (Ktrans,Kep,Ve,Vp) of every case were calculated using the pharmacokinetic model.The ROI was drawn on the solid portion of the lesion.And the histogram parameters,including mean,standard deviation,kurtosis,skewness and 90th percentiles,were calculated.Comparison of the histogram parameters(Ktrans,Kew Ve,Vp) between the tumors with different grades was conducted using the MannWhitney U test.Receiver operating characteristic (ROC) curve was constructed to determine the diagnostic efficacy of every histogram parameter,and intra-class correlation coefficients (ICC) were used to determine the diagnostic ability and reproducibility of the parameters.Results:The mean,standard deviation,kurtosis,skewness and 90th percentiles values of Ktrans in HGG were significantly higher than that in LGG(P＜0.05).With ROC analysis,all the parameters showed high diagnostic efficiency in the differentiation between high and low grade gliomas,of which the skewness of Kt value had the highest accuracy.The Ktrans value showed high reproducibility.Conclusion:DCE-MRI with histogram analysis has an important clinical value in the grading of gliomas.