多体素质子磁共振波谱检测非器质性颞叶癫痫患者海马亚区代谢变化

Multi-Voxel Proton Magnetic Resonance Spectroscopy to Examine Metabolic Changes in Hippocampal Subregions in Patients with Non-Lesional Temporal Lobe Epilepsy

目的通过研究多体素氢质子磁共振波谱成像(1H-MRS)N-乙酰天冬氨酸(NAA)/[胆碱(Cho)+肌酸(Cr)]比值在海马亚区的改变,探讨1H-MRS在颞叶癫痫(TLE)中的定侧价值。方法对60例经临床诊断为TLE的患者及60名年龄相匹配的健康对照组行常规MRI和1H-MRS检查。测量癫痫组和对照组海马亚区NAA/(Cho+Cr)比值。以NAA/(Cho+Cr)比值的阈值和NAA/(Cho+Cr)比值的双侧差异作为TLE癫痫灶的定侧标准。结果两名具有十年以上工作经验的放射科医师盲法测量的重复性较好[组内相关系数(ICC)=0.822~0.869]。对照组海马各亚区间NAA/(Cho+Cr)差异无显著性(P>0.05),TLE组海马各亚区△NAA/(Cho+Cr)值均大于对照组,差异有统计学意义(P<0.05)。TLE各亚区间,海马头部的NAA/(Cho+Cr)最低,△NAA/(Cho+Cr)比值差异最大,且NAA/(Cho+Cr)值明显低于△NAA/(Cho+Cr)比值,△NAA/(Cho+Cr)比值明显高于对照组各亚区,差异具有统计学意义(P<0.05),而TLE组海马体尾部NAA/(Cho+Cr)和△NAA/(Cho+Cr)比值差异无统计学意义(P>0.05)。以海马头部的NAA/(Cho+Cr)比值<0.65和△NAA/(Cho+Cr)比值>0.03作标准来确定癫痫侧,相应的曲线下面积(AUC)、敏感度和特异度分别为0.812、76.7%和85.5%。结论TLE患者的海马代谢损伤在不同亚区之间不同。与海马体尾部相比,海马头部更容易发生损伤。以海马头部作为1H-MRS定侧癫痫灶的感兴趣区(ROI),有助于提高定侧的准确率。

Objective The present study aimed to evaluate the role of multi-voxel proton magnetic resonance spectroscopy(MRS)in the lateralization of temporal lobe epilepsy(TLE)by investigating the N-acetylaspartate(NAA)/choline(Cho)+creatine(Cr)[NAA/(Cho+Cr)]ratios in hippocampal subregions.Methods Magnetic resonance imaging(MRI)followed by proton MRS(1H-MRS)was performed in 60 patients with a clinical diagnosis of TLE.MRI and1H-MRS were also performed in 60 healthy control subjects of comparable age.NAA/(Cho+Cr)ratios in hippocampal subregions were measured.A threshold value for the NAA/(Cho+Cr)ratio and bilateral differences in NAA/(Cho+Cr)ratios were used as lateralization criteria.Results Two radiologists with more than 10 years-experience had good interobserver reproducibility of blind measurement(ICC=0.822-0.869).There was no significant difference in NAA/(Cho+Cr)in each subregion of hippocampus in the healthy control group(P>0.05).The△NAA/(Cho+Cr)ratios in each subregions of hippocampus in the TLE group were higher than those in the control group,and the difference was statistically significant(P<0.05).Among the subregions of TLE,the NAA/(Cho+Cr)in the head of hippocampus in TLE group was the lowest,and the difference of NAA/(Cho+Cr)ratio was the largest,and the NAA/(Cho+Cr)value was significantly lower and NAA/(Cho+Cr)ratio was significantly higher than that in the control group(P<0.05),while the difference of NAA/(Cho+Cr)and NAA/(Cho+Cr)ratio in the body and tail of hippocampus in TLE group was not statistically significant(P>0.05).A NAA/(Cho+Cr)ratio of<0.65 and a△NAA/(Cho+Cr)ratio of>0.03 in the hippocampal head were used as standards to lateralize TLE.The corresponding area under the curve,sensitivity,and specificity were 0.812,76.7%,and 85.5%,respectively.Conclusion Metabolic impairments in the hippocampi of patients with TLE were not equal between subregions.Specifically,the hippocampal head was more susceptible to metabolic impairment compared with the hippocampal body and tail.Taking the head of hippocampus as the region of interest of1H-MRS lateralization of epileptic foci is helpful to improve the accuracy of lateralization.