不同病理分级儿童脑胶质瘤MR灌注成像

Glioma grading in children brain:using MR PWI

目的:采用磁共振灌注成像(MR PWI)探讨儿童不同级别脑胶质瘤的血流灌注特点及其临床诊断价值。方法:35例脑胶质瘤均经手术病理证实,其中Ⅰ～Ⅱ级胶质瘤(低级别胶质瘤组)28例,Ⅲ级胶质瘤(高级别胶质瘤组)7例,计算病灶内异常高灌注中心区(a区)、异常低灌注中心区(b区)、负性增强积分(NEI)伪彩图与T1WI增强图上不匹配区(c区)的相对NEI值(rNEI)及NEI伪彩图与T1WI增强图像上病变面积的比值(N/C),分析rNEI及N/C与肿瘤病理学分级的相关性。结果:高级别胶质瘤组中a区和c区的rNEI分别为8.39±1.91和5.43±0.52,均大于低级别胶质瘤组(分别为5.10±2.05和4.05±0.66),差异均具有极显著性意义(P<0.01)。高级别及低级别胶质瘤组NEI伪彩图上异常灌注区面积均大于T1WI增强图像上的异常强化区,N/C分别为1.06±0.11和1.45±0.09,差异具有极显著性意义(P<0.01)。结论:采用正确的研究方法MR PWI能有效分析儿童脑胶质瘤的血流灌注情况,对儿童脑胶质瘤的浸润范围的界定及术前分级均能有效判断。

Objective：To study the perfusion characteristics and clinical diagnostic value of the magnetic resonance perfusion weighted imaging（MR PWI） for grading of glioma in children brain.Methods：GE 1.5T HDx Echospeed Plus MRI scanner were used and double dosage（0.2mmol/kg） Gd-DTPA was given.Children（n=35） with brain glioma including 28 cases grade I-II（group A） and 7 cases grade Ⅲ（group B） underwent MR PWI with the injection rate ranged from 2~4ml/s,and all cases were confirmed by pathology.After MR PWI scanning,negative enhancement integral（NEI） maps were obtained.NEI values and Relative NEI（rNEI） were studied by NEI maps.The study indexes included the rNEI of maximum hyper perfusion center（ROI-a）,minimum hypo perfusion center（ROI-b）,mismatch region of NEI maps and contrast-enhanced MR T1WI（ROI-c）,the ratio of focus area in NEI maps and contrast-enhanced MR T1WI（N/C ratio） was studied too.All the study indexes of MR PWI were correlated with pathology.Results：The rNEI of ROI-a and ROI-c in group B was greater than that in group A（P0.01）.The abnormal perfusion areas of NEI maps were bigger than the abnormal enhanced areas of T1WI in the two groups.The N/C ratio was 1.06±0.11 in group A and 1.45±0.09 in group B,and there were significant statistical differences in the two groups（P0.01）.Conclusion：MR PWI is helpful to the grading and extent definition of glioma in children brain if appropriate methods are adopted.