磁共振动态磁敏感对比增强成像在术前脑胶质瘤分级诊断及IDH突变状态评估中的应用价值

The application of dynamic susceptibility contrast enhanced MR imaging in preoperative glioma grading and assessment of IDH mutation status

目的:探讨动态磁敏感对比增强磁共振成像在胶质瘤术前分级诊断及IDH突变状态评估中的应用价值。方法:纳入我院经病理确诊脑胶质瘤71例[30例低级别胶质瘤(low-grade glioma,LGG),41例高级别胶质瘤(high-grade glioma,HGG),41例IDH突变型(isocitrate dehydrogenase mutant),30例IDH野生型(IDH wild type)]。术前均行常规MR平扫、增强、DWI及DSC-MRI,运用后处理工作站对各MR图像进行分析,分别测量肿瘤实质区、瘤周水肿区及对侧正常脑白质区的相对脑血容量(relative cerebral blood volume,rCBV)、相对脑血流量(relative cerebral blood flow,rCBF)、平均通过时间(mean transit time,MTT)以及达峰时间(time to peak,TTP),并计算规范化(肿瘤实质区/对侧正常脑白质区)肿瘤实质区的各参数值。所得数据经统计软件进行组间比较,并与病理分级及IDH突变状态进行相关性以及各参数诊断效能的分析。结果:肿瘤实质区,LGG的规范化rCBF和rCBV值低于HGG(P<0.05),IDH突变型的规范化rCBF和rCBV值低于IDH野生型(P<0.05)。规范化的rCBF,rCBV值与高、低肿瘤级别间呈正相关(P<0.01),与IDH突变状态呈负相关(P<0.01)。对高、低级别胶质瘤的诊断,以rCBV值的曲线下面积最大(0.849),诊断阈值为2.2 mL/100 g,敏感性为87.8%,特异性为76.7%。对IDH突变状态的评估,以rCBV值的曲线下面积最大(0.741),诊断阈值为3.6 mL/100 g,敏感性为62.2%,特异性为90.9%。DSC预测高、低级别胶质瘤分级诊断的准确性为81.7%,预测IDH突变状态的准确性为80.0%。结论:DSC是脑胶质瘤术前无创分级诊断及评估IDH突变状态的有效影像学技术,可在术前检测胶质瘤灌注信息判断其级别及IDH突变状态,为患者的精确诊治提供帮助。

Objective:To investigate the application value of dynamic susceptibility contrast enhanced MR imaging in the preoperative grading of gliomas and assessment of IDH mutation status.Methods:Seventy-one patients with pathologically confirmed gliomas(30 cases of low-grade glioma,41 cases of high-grade glioma.41 cases of isocitrate dehydrogenase mutant,30 cases of IDH wild type)received conventional MR plain scan,enhanced scan,diffusion weighted imaging and dynamic susceptibility contrast enhanced MR imaging.The four parameters[relative cerebral blood volume(rCBV),relative cerebral blood flow(rCBF),mean transit time(MTT),time to peak(TTP)]of three areas[the tumor lesion area,peripheral edema and contralateral normal-appearing white matter(CNAWM)]were measured,then the parameters of normalized(tumor lesion area/CNAWM)were calculated.The data was compared between low and high grade glioma and the correlation of the parameters with pathological grade was made.Results:In the tumor lesion area,the normalized rCBF and rCBV values of LGG were lower than those of HGG(P<0.05).The normalized rCBF and rCBV values were lower for IDH mutant than IDH wild type(P<0.05).The normalized rCBF and rCBV values were positively correlated with high and low tumor levels(P<0.01),whereas negative correlations were observed between rCBF,rCBV and IDH mutational status(P<0.01).For the diagnosis of high and low grade glioma,the area under the curve of rCBV value was the largest(0.849).The diagnostic threshold was 2.2 mL/100 g.The sensitivity was 87.8%,and the specificity was 76.7%.For the evaluation of IDH mutation status,the area under the curve of rCBV value was the largest(0.741).The diagnostic threshold was 3.6 mL/100 g,the sensitivity was 62.2%,and the specificity was 90.9%.The accuracy of DSC in predicting grade diagnosis of high and low grade glioma was 81.7%,and that of IDH mutation status was 80.0%.Conclusion:DSC is an effective imaging technique for preoperative noninvasive graded diagnosis of glioma and assessment of IDH mutation status.It can detect the perfusion information of glioma before surgery to determine its grade and IDH mutation status,and provide help for accurate diagnosis and treatment of patients.