定量动态增强 MRI在脑胶质瘤术前分级中的应用研究

目的：探讨定量动态增强 MRI(T1-DCE MRI)在脑胶质瘤术前分级中的应用价值。方法经手术病理证实的80例脑胶质瘤患者(WHOⅠ级20例,Ⅱ级20例,Ⅲ级20例,Ⅳ级20例)均行3T 常规 MR 增强及 T1-DCE MRI 检查,原始灌注图像数据经 GE Omni Kinetic 软件处理,获得容量转移常数(Ktrans )、回流速率常数(Kep )和血管外细胞外间隙容积比(Ve )图,选择感兴趣区(ROI),计算 Ktrans 、Kep 和 Ve 值。不同级别胶质瘤 Ktrans 、Kep 和 Ve 值与病理分级进行 Pearson 相关性分析,不同级别胶质瘤 Ktrans 、Kep 和 Ve 值比较采用单因素方差分析。绘制受试者工作特征曲线(ROC)分析灌注参数的诊断特异性、敏感性。结果Ktrans 、Kep 和Ve 值与病理学分级具有明显相关性(r=0.951,0.804,0.766)。Ktrans 值不同级别胶质瘤患者间比较有明显的统计学差异,Kep 值除Ⅱ级和Ⅲ级间比较无差异外,余不同级别间比较均有统计学差异,Ve 值除Ⅰ级和Ⅱ级,Ⅲ级和Ⅳ级间比较无差异外,余不同级别间比较有统计学差异。根据 ROC,Ktrans 对于诊断不同级别胶质瘤具有较高的敏感性和特异性。以 Ktrans 值0.160,0.420和0.935为最佳诊断切点值,诊断不同级别胶质瘤的敏感性分别为90%,95%和95%,特异性分别为95%,95%和85%。结论通过 T1-DCE MRI 所得参数Ktrans 值对不同级别胶质瘤微血管灌注状态进行定量分析,可以评估肿瘤血管血脑屏障的破坏程度,在术前较为精确地评价胶质瘤级别。

Application research of quantitative dynamic contrast enhanced MRI in preoperative grading of brain glioma

Objective To study appliction value of quantitative dynamic contrast enhanced MRI(T1-DCE MRI)in preoperative grading of brain glioma.Methods 80 patients who were pathologically confirmed with a tumor grade (WHO grade Ⅰ 20 cases, grade Ⅱ 20 cases,grade Ⅲ 20 cases and grade Ⅳ 20 cases).All patients were examined with MR enhancements and T1-DCE MRI. The original perfusions imaging datas were analyzed using the GE Omni Kinetic software,which produced the transfer constant (Ktrans )map,the rate constant (Kep )map and fractional volume (Ve )map.Choose ROI and get values of Ktrans ,Kep and Ve .Pearson correlation was carried out to analyze the correlation between values of Ktrans ,Kep ,Ve of different grades of gliomas and pathology classifications.The Ktrans ,Kep and Ve values of the different grade gliomas were statistically analyzed using an ANOVA .Receiver operator characteristics (ROC)curve was used to analyze sensitivity and specificity of permeability parameters.Results The Ktrans ,Kep and Ve values of each levels has a strong correlation with pathological grading (r=0.95 1,0.804,0.766).There was obviously statistically significant difference between different grade groups(P < 0.01 )by Ktrans .Kep values have statistically difference between different grades except grade Ⅱ and Ⅲ.Ve values were different between different grades except grade I andⅡand grade Ⅲ and IV.Accord-ing to ROC curve,Ktrans seemed to be a better parameter for evaluating the tumor grade with the highest sensitivity and specificity. With the cutoff thresholds of Ktrans of 0.1 60,0.420 and 0.935,different grades of glioma can be differentiated with sensitivities of 90%,95%,95% and specificities of 95%,95%,85% respectively.Conclusion Quantitative analysis of microcirculation perfusion status of different grade gliomas by Ktrans values obtained from T1-DCE MRI can assessment the degree of the destruction of the blood brain barrier and evaluate the grade of gliomas more accurately before operation.