^(11)C-MET PET/CT筛查幕上较低级别胶质瘤IDH和1p/19q分子分型的应用价值

Application of ^(11)C-MET PET/CT in screening isocitric dehydrogenase and 1p/19q status in supratentorial lower-grade gliomas

目的评估^(11)C-蛋氨酸(^(11)C-methionine,^(11)C-MET)正电子发射型计算机断层显像/电子计算机断层显像(positron emission tomography/computed tomography,PET/CT)半定量参数在筛查幕上较低级别胶质瘤(lower-grade glioma,LrGG)异柠檬酸脱氢酶(isocitric dehydrogenase,IDH)突变以及1p/19q共缺失状态的应用价值。方法分析37例幕上较低级别胶质瘤患者术前^(11)C-MET PET/CT图像以及病理学资料。测量^(11)C-MET PET/CT图像上病灶最大肿瘤/正常组织摄取比值(maximum tumor/normal tissue uptake ratio,TNR_(max))、平均肿瘤/正常组织摄取比值(mean TNR,TNR_(mean))以及肿瘤/正常组织摄取比值峰值(peak TNR,TNR_(peak))。根据IDH基因突变以及1p/19q共缺失状态,将患者分为3组:IDH野生型(IDH^(wt)),IDH突变-1p/19q共缺失型(IDH^(mut) 1p/19q^(del))以及IDH突变-1p/19q非共缺失型(IDH^(mut) 1p/19q^(int))。比较不同分子分型的LrGG间的TNR_(max)、TNR_(mean)以及TNR_(peak)。使用受试者工作特征(receiver operating characteristic,ROC)曲线分析单参数对于IDH突变和1p/19q共缺失状态的筛查效能。采用Logistic回归建立联合诊断模型,对预测概率进行ROC分析,评估多参数联合筛查效能。结果TNR_(max)、TNR_(mean)、TNR_(peak)在3组LrGG间的差异有统计学意义(P<0.05)。IDH^(wt)组TNR_(max)、TNR_(mean)、TNR_(peak)最高,其次为IDH^(mut) 1p/19q^(del)组,IDH^(mut) 1p/19q^(int)组最低。IDH wt LrGG的TNR_(max)、TNR_(mean)、TNR_(peak)均高于IDH^(mut) LrGG组,差异有统计学意义(P<0.05)。ROC曲线分析结果显示,TNR_(max)、TNR_(mean)、TNR_(peak)筛查LrGG IDH突变的曲线下面积(area under the curve,AUC)分别为0.827、0.847、0.807,以3.09、1.84和2.58为阈值,准确率分别为70.3%、75.7%和75.7%,采用Logistic回归分析构建的筛查模型能提高诊断准确率,AUC值为0.943,灵敏度、特异度和准确率分别为100%、83.3%和94.6%。TNR_(max)、TNR_(mean)、TNR_(peak)筛查LrGG 1p/19q共缺失的AUC分别为0.766、0.792、0.812,以3.35、1.44和2.02为阈值,准确率分别为76.0%、80.0%和80.0%。Logistic筛查模型不能提高诊断效能。结论^(11)C-MET PET/CT有助于筛查幕上较低级别胶质瘤IDH突变以及1p/19q共缺失状态。多参数联合能够提高对于IDH基因突变的筛查效能。

Objective To evaluate the value of ^(11)C-methionine(^(11)C-MET)positron emission tomography/computed tomography(PET/CT)in screening isocitric dehydrogenase(IDH)mutation and 1p/19q co-deletion status in supratentorial lower-grade glioma(LrGG).Methods The preoperative ^(11)C-MET PET/CT images and pathological data of 37 patients with lower-grade supratentorial glioma were retrospectively analyzed.The maximum tumor/normal tissue ratio(TNR_(max)),mean tumor/normal tissue ratio(TNR_(mean))and peak tumor/normal tissue ratio(TNR_(peak))of lesions on were measured.According to IDH gene mutation and 1p/19q co-deletion status,patients were divided into three groups:IDH wild type(IDH^(wt));IDH^(mut)ation-1p/19q co-deletion type(IDH^(mut) 1p/19q^(del))and IDH^(mut)ation-1p/19q^(int)act type(IDH^(mut) 1p/19q^(int)).TNR values of different molecular subtypes of LrGG were compared with each other.The differential diagnostic efficacy of semi-quantitative parameters for different molecular subtypes of LrGG was analyzed using receiver operating characteristic(ROC)curve.Logistic regression was used to establish a joint diagnostic model,and the ROC analysis was conducted to evaluate the predictive efficiency of joint diagnostic model.Results There were significant differences in TNR_(max),TNR_(mean) and TNR_(peak) among the three groups of LrGG(P<0.05).TNR_(max),TNR_(mean) and TNR_(peak) were the highest in the IDH^(wt) group,followed by the IDH^(mut) 1p/19q^(del) group.Semiquantitative values were the lowest in the IDH^(mut) 1p/19q^(int) group.The TNR_(max),TNR_(mean) and TNR_(peak) of IDH^(wt) LrGG were higher than those of IDH^(mut) LrGG,and the difference was statistically significant(P<0.05).The results of ROC analysis showed that the area under the curves(AUCs)of TNR_(max),TNR_(mean),and TNR_(peak) for screening IDH^(mut)ations were 0.827,0.847,and 0.807,with thresholds of 3.09,1.84,and 2.58,respectively,and the accuracy rates were 70.3%、75.7%and 75.7%,respectively.The screening model based on Logistic regression analysis can improve diagnostic accuracy,with an AUC value of 0.943,sensitivity,specificity,and accuracy of 100%,83.3%,and 94.6%,respectively.The TNR_(max),TNR_(mean) and TNR_(peak) of IDH^(mut) 1p/19q^(del) LrGG were significantly higher than those of IDH^(mut) 1p/19q^(int) LrGG(P<0.05).The AUCs of TNR_(max),TNR_(mean),and TNR_(peak) for predicting 1p/19q co-deletion of IDH^(mut) LrGG were 0.766,0.792,and 0.812,with thresholds of 3.35,1.44,and 2.02,respectively,and the accuracies were 76.0%,80.0%,and 80.0%,respectively.Joint diagnostic model cannot improve diagnostic efficiency.Conclusion ^(11)C-MET PET/CT is helpful for screening IDH^(mut)ation and 1p/19q co-deletion status in supratentorial lower-grade gliomas.The combination of multiple parameters can improve the efficiency of screening IDH gene mutation.