儿童脑部磁共振灌注成像技术的初步研究

The study of MR PWI in the brain of children

目的:研究磁共振灌注成像(MR PWI)技术应用于儿童脑部血流灌注分析的可行性及其方法。方法:使用GE1.5T HDx echo speed plus MRI扫描仪,头线圈,PWI序列,双倍剂量MRI造影剂(马根维显,0.2mmol/kg);实验组前瞻性研究儿童患者45例,根据患儿体重及MRI造影剂注射速度(2～4ml/s)分为4组、8个亚组;对照组搜集成人患者20例,MRI造影剂注射速度4ml/s。MR PWI图像资料处理得到负性增强积分(NEI)伪彩图并测量相应感兴趣区的NEI值与相对负性增强积分(rNEI)。结果:本研究表明体重<20kg的患儿MRI造影剂注射速度须达到3ml/s以上时能形成良好的MR PWI信号-时间曲线;造影剂注射速度为2ml/s时,仅适用于体重<10kg的患儿;体重>20kg患儿必须使用>3ml/s的造影剂注射速度,推荐速度为4ml/s。实验组患儿NEI值的偏差显著(标准差13.69～22.54),与对照组的差异具有显著的统计学意义(P<0.001);而rNEI值的偏差不明显(标准差0.05～0.08),与对照组的差异无显著的统计学意义(P>0.001)。结论:在特定的条件下MR PWI能有效分析儿童脑部血流灌注情况,为MR PWI在儿科领域的应用研究迈出重要的一步。

Objective：To study the feasibility and method of magnetic resonance perfusion weighted imaging（MR PWI） in children＇s brain.Methods：GE 1.5T HDx echo speed plus MRI scanner were used and double dosage（0.2mmol/kg） Gd-DTPA was given.In the study group,45 children underwent MR PWI with the injection speed ranged from 2～4ml/s according to the limit of the vein.In control group,20 adults underwent MR PWI with the injection speed of 2～4ml/s.After the MR PWI scan,negative enhancement integral（NEI） maps were obtained.NEI values and relative NEI（rNEI） were studied in NEI maps.Results：The study showed that the children with body weight 20kg and Gd-DTPA injection speed of 3ml/s or with body weight 20kg and injection speed 3～4ml/s could get satisfactory PWI curves.Children 10kg with injection speed of 2ml/s could get available PWI curves.The NEI values of the studied group had a marked standard deviation（13.69～22.54） and there were significant statistical differences between the two groups（P0.001）.But rNEI of studied group had a slight standard deviation（0.05～0.08） and there were no significant statistical differences between the two groups（P0.001）.Conclusion：MR PWI could be used in the research of children brain perfusion if the injection speed was high enough.This study is very important to the research of cerebral MR PWI in pediatrics.