18-F-FDG PET/CT儿童脑肿瘤高低级别诊断

目的：探讨^18 F-FDG PET/CT对儿童脑肿瘤高低级别诊断的价值。方法：回顾性分析19例脑肿瘤患儿（男10例，女9例，平均年龄2．13岁）术前PET/CT影像学表现。所有病例均经手术病理证实。图像分析分别按目测法、半定量法判定，以术后病理为金标准验证，分为高、低级别两组，用t检验比较两组代谢差别，通过ROC曲线获得曲线下面积（AUC）及最佳诊断界点（ODC）。结果：低级别肿瘤8例（Ⅰ级4例，Ⅱ级4例），高级别肿瘤11例（Ⅲ级4例，Ⅳ级7例）。两组最大标准化摄取值（SUVmax）间差异明显，高级别组代谢水平明显高于低级别组（t＝-2．394，P＝0．028＜0．05），且与病理分级显著相关（r＝0．478，P＝0．039＜0．05）。余半定量分析方法中，肿瘤白质比（T/W）两组间存在差异（t＝-2．579，P＝0．020＜0．05）。SUVmax 的 ROC AUC 为0．801（95％ CI：0．579-1．0，P＝0．029），ODC 为3．3；L/W 的AUC为0．807（95％ CI：0．585-1．0，P＝0．026），ODC 为1．94。结论：18 F-FDG PET/CT 显像对儿童脑肿瘤的级别分析有一定的价值，本文所指的半定量方法中SUVmax及T/W诊断意义较大，且前者与病理分级明显相关。

Preliminary study of ^18 F-FDG PET/CT in distinguishing high and low grade in children brain tumors

Objective：To explore the value of ^18 F-FDG PET/CT in distinguishing high and low grade pediatric brain tumor.Methods：^18F-FDG PET/CT were performed in 19 children （male 10,female 9,mean age 2.13y）with brain tumor be-fore surgery.All the cases were pathologically confirmed after surgery.PET/CT images were reviewed by visual observation and semiquantitative method.The patients were divided into two groups as high and low grade.T-test was used to evaluate the statistical differences between the two groups.The area under the curve （AUC）and optimal diagnostic cut-off （ODC） were obtained through ROC curves for this study.Results：There were eight cases in the low grade group （gradeⅠand Ⅱwas 4 each）and 1 1 in the high group （grade Ⅲ4 ,and grade Ⅳ 7 ）.The maximum FDG uptake （SUVmax）was significantly different between the two groups （t= -2.394,P= 0.028〈0.05）,and SUVmax was siginificantly correlated with pathological results （r= 0.478,P= 0.039〈0.05）;As for the semiquantitative study,only the ratio of tumor/white matter （T/W） was significantly different between the groups （t= -2.579,P= 0.020〈0.05）.AUC for SUVmax levels was 0.801 （95%CI：0.579-1.0,P= 0.029）.The ODC of SUVmax was 3.3.AUC for L/W was 0.807 （95% CI：0.585-1.000,P= 0.026） with the ODC of 1.94.Conclusion：18 F-FDG PET/CT could be useful to distinguish high and low grade pediatric brain tumors.SUVmax and T/W had highest diagnostic value by use of semiquantitative method.SUVmax was siginificantly correlated with pathological results.