扩散峰度成像直方图在脑胶质瘤分级中的应用

目的探讨MRI扩散峰度成像(diffusion kurtosis imaging,DKI)直方图分析在脑胶质瘤术前分级诊断中的价值。方法通过对经手术及病理证实的45例脑胶质瘤患者的DKI图像资料的回顾性分析。选取整个肿瘤的实质区作为感兴趣容积(volume of interest,VOI)进行直方图分析,获得表观扩散系数(apparent diffusion for gaussian distribution,Dapp)及表观扩散峰度(apparent kurtosis coefficient,Kapp)的直方图参数。使用独立样本t检验及Mann-Whitney U检验评估高级别和低级别神经胶质瘤各直方图参数间的差异。受试者工作特征曲线(receiver operating characteristic,ROC)用于分析各直方图参数对胶质瘤分级的诊断效能。应用组内相关系数(intra-class correlation coefficient,ICC)分析数据测量的可重复性。结果DKI直方图参数在高低级别胶质瘤中有显著性差异(P<0.05)。Dapp直方图参数中Dapp-10th的诊断效能最高,曲线下面积(area under the curve,AUC)、敏感性和特异性分别为0.856、74.1%、83.3%。Kapp直方图参数中Kapp-30th的诊断能力最高,AUC、敏感性和特异性分别为0.905、81.5%、94.4%。每个参数具有良好的观察者间信度,ICC范围为0.861~0.964。结论DKI直方图分析有助于提高低级别胶质瘤与高级别胶质瘤之间的鉴别诊断能力。

Application of histogram analysis of diffusion kurtosis imaging in grading glioma

Objective To explore the value of histogram analysis of diffusion kurtosis imaging(DKI)in glioma grading.Methods 45 patients with pathologically confirmed gliomas who underwent DKI were enrolled in this retrospective study.The VOI(volume of interest)covering the entire tumor was drawn on the original images,and then apparent diffusion for Gaussian distribution(Dapp)and apparent kurtosis coefficient(Kapp)were generated.The corresponding histogram parameters of Dapp and Kapp were calculated.The unpaired student’s t-test and mann-whitney U test were used to compare the histogram parameters of low grade gliomas(LGGs)and high grade gliomas(HGGs).The receiver operating characteristic(ROC)curve analysis was used to analyze the diagnostic ability of each parameter.Intra-class correlation coefficient(ICC)was used to evaluate the inter-reader agreement of quantitative measurements.Results Histogram quantitative parameters of DKI were significantly different between HGGs and LGGs(P<0.05).In the histogram parameters of Dapp,the Dapp-10th had the best diagnostic performance.The area under the curve(AUC),sensitivity and specificity were 0.856,74.1%and 83.3%,respectively.In the histogram parameters of Kapp,the diagnostic ability of kapp-30th was the best.The AUC,sensitivity and specificity were 0.905,81.5%and 94.4%,respectively.Each histogram quantitative parameter had excellent inter-observer reliability,and the ICC range was 0.861~0.964.Conclusion Histogram analysis of DKI may help to improve the differentiation between LGGs and HGGs.