MRI动脉自旋标记技术检出小儿药物难治性癫痫致痫灶的价值

Value of MRI arterial spin labeling technique on the detection of epileptogenic zone in children with drug resistant epilepsy

目的探讨MRI动脉自旋标记(ASL)技术检出小儿药物难治性癫痫(DRE)致痫灶(EZ)的价值。方法前瞻性收集2018年3月至2019年12月北京大学第一医院收治的28例DRE患儿, 对其行结构MRI、ASL及PET-CT检查。所有患儿均行手术治疗, 以术中皮层脑电图结合术后MRI复查结果作为定位EZ金标准。28例患儿共切除29个EZ。根据病理结果分为局灶性脑皮质发育不良(FCD)Ⅰb和Ⅱa组(12个)、FCDⅡb组(11个)和脑皮质发育畸形(MCD)组(6个)。观察结构MRI中有无可以诱发癫痫的异常改变, 分为结构MRI正常组(13个)和结构MRI异常组(16个)。观察脑血流量(CBF)图和PET图像异常区域与金标准的位置关系, 计算EZ的准确检出率。于CBF图和PET图像上勾画感兴趣区(ROI), ROI位于EZ、EZ对侧镜像区(EZCZ)、EZ邻近区(EZAZ)、EZAZ对侧镜像区(EZAZCZ), 测量CBF和最大标准吸收值(SUV_(max)), 计算EZ及EZAZ对应的CBF和SUV_(max)的不对称率(AI)。采用单因素方差分析比较4个区域和3种病理类型间CBF、SUV_(max)及AI的差异, 采用独立样本t检验比较结构MRI正常组与结构MRI异常组间AI的差异。结果 CBF图中, EZ准确检出率为89.7%(26/29), 其中灌注减低24个、灌注增高2个。24个灌注减低的EZ中, EZ、EZCZ、EZAZ、EZAZCZ的CBF值差异有统计学意义(F=8.79, P<0.001)。PET-CT中, EZ准确检出率为93.1%(27/29), 其中代谢减低25个、代谢增高2个。25个代谢减低的EZ中, EZ、EZCZ、EZAZ、EZAZCZ的SUV_(max)差异有统计学意义(F=6.40, P=0.001)。结构MRI异常组EZ的CBF和SUV_(max)的AI均大于结构MRI正常组, 差异有统计学意义(t=3.34、3.09, P=0.002、0.004)。FCD Ⅰb和Ⅱa组、FCDⅡb组、MCD组间CBF和SUV_(max)的AI差异无统计学意义(F=2.05、1.54, P=0.149、0.234)。结论 ASL技术可对EZ的准确检出率较高, 结构MRI异常的EZ的CBF和SUV_(max)的改变程度大于结构MRI正常的EZ, 不同病理类型间EZ的CBF和SUV_(max)改变程度无明显差异。

Objective To explore the value of arterial spin labeling(ASL)in detecting epileptogenic zone(EZ)in children with drug-refractory epilepsy(DRE).Methods From March 2018 to December 2019,28 children with DRE were collected prospectively in Peking University First Hospital.Structural MRI,ASL sequence,and PET-CT were performed on 28 DRE children.All children underwent surgical treatment.Intraoperative electrocorticogram findings combined with postoperative MRI results were considered the gold standard for locating EZ.A total of 29 EZ were resected in 28 children.Based on the pathological results,the EZ was divided into focal cortical dysplasia(FCD)Ⅰb andⅡa group(n=12),FCDⅡb group(n=11)and malformation of cortical dysplasia(MCD)group(n=6).Structural MRI was observed for finding any abnormal changes that could induce epilepsy and was divided into the normal MRI group(n=13)and the abnormal MRI group(n=16).The spatial relationship between abnormal areas in the cerebral blood flow(CBF)map and PET images and the gold standard was observed,and the accurate detection rate of EZ was calculated.The region of interest(ROI)on CBF and PET images was drawn.ROIs were defined as EZ,EZ contralateral zone(EZCZ),EZ adjacent zone(EZAZ),EZAZ contralateral zone(EZAZCZ).The CBF and maximum standardized uptake value(SUV_(max))were measured,and the asymmetry index(AI)value of EZ and EZAZ of CBF and SUV_(max) was calculated respectively.One-way ANOVA was used to compare the difference among 4 regions and 3 pathological types of CBF,SUV_(max),and AI.The independent sample t-test was used to compare the difference in AI between normal and abnormal MRI groups.Results In CBF map,the EZ was accurately localized in 89.7%(26/29)of the lesions,in which 24 EZ had decreased perfusion,and 2 EZ had increased perfusion.Among the 24 EZ with decreased perfusion,the CBF of EZ,EZCZ,EZAZ,and EZAZCZ were significantly different(F=8.79,P<0.001).In PET-CT,the EZ was accurately localized in 93.1%(27/29)of the lesions,in which 25 EZ had decreased metabolism,and 2 EZ had increased metabolism.Among the 25 EZ with decreased metabolism,the SUV_(max) of EZ,EZCZ,EZAZ,and EZAZCZ were significantly different(F=6.40,P=0.001).The AI value of CBF and SUV_(max) of EZ in the abnormal MRI group were larger than those of the normal MRI group,and the difference was statistically significant(t=3.34,3.09,P=0.002,0.004).There was no statistical difference in the AI values of CBF and SUV_(max) among FCDⅠb andⅡa group,FCDⅡb group and MCD group(F=2.05,1.54,P=0.149,0.234).Conclusions ASL technology is accurate in detecting EZ.The changes in perfusion and metabolism of normal structural MRI EZ are greater than abnormal structural MRI EZ.There is no obvious difference in CBF and SUV_(max) changes in different pathological EZ.