结合型局灶性脑皮层发育不良的MRI表现

MRI features of associated focal cortical dysplasia

目的探讨结合型局灶性脑皮层发育不良(FCDⅢ型)的MRI影像表现。方法回顾性分析经临床、手术及病理证实的158例符合FCDⅢ型的MRI影像资料,总结FCDⅢ型的异常影像表现特点。结果 158例FCDⅢ型病灶中,有147例位于颞叶(比例约为93.0%),120例FCDⅢa型的FCD病灶均为前颞叶脑组织。113例FCDⅢ型中FCD病灶影像异常,阳性率约71.5%,其中FCDⅢa、FCDⅢb型、FCDⅢc型、FCDⅢd型影像阳性率分别为81.7%、47.8%、50%、11.1%。FCD病灶异常影像表现为病灶区灰白质分界稍模糊(83.2%),皮层T_2FLAIR序列信号轻度增高(69.9%),皮层轻度增厚(49.6%),皮层T2WI序列信号略有增高(20.4%),局部脑叶萎缩(14.2%)等影像特点。结论 FCDⅢ型中FCD病灶影像异常表现轻微,常为多个轻度异常影像相互存在,发生部位以颞叶为主,FCDⅢa型发病率最高,故发生于颞叶的海马硬化、肿瘤、血管畸形等病变时,需要排除存在FCDⅢ型可能,尤其是在发现海马硬化时,要注意对前颞叶轻微异常影像表现提高警惕,对提高癫痫外科术前及预后评估有重要意义。

Objective To investigate the MRI features of focal cortical dysplasia（FCD type Ⅲ） coexisting with other brain lesions. Methods MRI of 158 histologically proven FCD type Ⅲ was analyzed retrospectively and the imaging features were summarized. Results FCD type Ⅲ was located in the temporal lobe（147 / 158, 93.0%） with type Ⅲ a（120 / 158, 75.9%） in the anterior temporal lobe. MRI abnormalities were found in 113 FCD type Ⅲ cases（71.5%） with positive MRI findings in 81.7%（type Ⅲ a）, 47.8%（ Ⅲ b）, 50.0%（ Ⅲ c）, and 11.1%（ Ⅲ d）. The FCD lesions appeared slightly T2-hyperintense on FLAIR-（69.9%）and T2-（20.4%） weighted images with slightly indistinct boundary between grey and white matter（83.2%）, mildly thickened cortex（49.6%）, or focal cerebral atrophy（14.2%）. Conclusion The FCD type Ⅲ lesions are more common in the temporal lobes and may coexist with hippocampal sclerosis, tumors, and vascular malformations. Subtle abnormalities in the anterior temporal lobes should raise suspicion of coexisting FCD type Ⅲa.