癫痫患儿海马急性损伤的MRI表现

MRI Manifestations of Hippocampus with Acute Injury in Children

目的研究癫痫患儿海马急性损伤的MRI表现,探讨其发病原因及转归,提高对海马急性损伤结构改变的认识。资料与方法回顾性分析经头颅MRI检查扩散加权成像（DWI）海马表现为高信号的8例癫痫患儿的临床及影像学资料,测量双侧海马体积及表观扩散系数（ADC）值,分析海马体积、T2WI信号变化及ADC值改变。结果 8例临床诊断为癫痫,其中7例有反复癫痫发作史。MRI检查距癫痫发作时间1-5 d。8例均为单侧海马体积增大,其中左侧6例,右侧2例,患侧海马体积为（2.096±0.570）cm^3,显著大于健侧（1.768±0.447）cm^3（t=-4.763,P〈0.01）。T2WI及FLAIR信号增高;DWI显示高信号,增高约25.52%。患侧ADC值为（0.763±0.049）×10^-3 mm^2/s,较健侧（0.859±0.054）×10^-3 mm^2/s降低（t=9.598,P〈0.01）。3例此次发作前曾由于热性惊厥或抽搐发作行MRI检查,双侧海马未见异常。3例3-5个月后复查,患侧海马体积缩小;T2WI及FLAIR信号仍较高;ADC值增高15.6%,表现为海马硬化。结论癫痫可以引起海马急性损伤,表现为海马肿大,T2WI信号增加,ADC值下降;海马急性损伤发展为海马硬化。

Purpose To study the MRI manifestations of hippocampus with acute injury in children with epilepsy, and to explore its causes and outcomes for a better understanding of the changes of hippocampal structure with acute injury.Materials and Methods The clinical and imaging data of 8 children with epilepsy whose hippocampus showed hyperintensity in DWI were retrospectively analyzed. The bilateral hippocampal volume and ADC values were measured; changes of hippocampal volume and T2WI signal and ADC value were also analyzed.Results Eight patients were clinically diagnosed as epilepsy, 7 cases had recurrent history of seizures. MRI was performed from 1 to 5 days after the onset of epilepsy. All the 8 patients had increased unilateral hippocampal volume, 6 of whom were on the left side and the other 2 were on the right side. The affected ipsilateral hippocampal volume was significantly higher than that on the contralateral side [（2.096±0.570） cm^3 and （1.768±0.447） cm^3, respectively,t=-4.763,P〈0.01]. The signals increased on T2WI and FLAIR; DWI showed hyperintensity with increase by approximately 25.52%. The affected ipsilateral ADC value was significantly lower than the contralateral one [（0.763±0.049）×10^-3 mm^2/s and （0.859±0.054）×10^-3 mm^2/s, respectively, t=9.598,P〈0.01]. No abnormalities were found in bilateral hippocampus when 3 patients underwent MRI due to febrile convulsions and seizures before the onset of epilepsy. The affected ipsilateral hippocampal volume reduced in 3 patients after 3 to 5 months;signal was still high on T2WI and FLAIR; ADC values increased by 15.6%, the imaging results indicated hippocampal sclerosis.Conclusion Epilepsy can cause acute injury in hippocampus which demonstrates hippocampus swelling, signal increase on T2WI, and reduced ADC value and may lead to hippocampal sclerosis.