Fredriksen Jason R, Carr Carrie M, Koeller Kelly K, Verdoorn Jared T, Gadoth Avi, Pittock Sean J, Kotsenas Amy L
Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.
Department of Neurology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.
Neuroradiology. 2018 Mar;60(3):239-245. doi: 10.1007/s00234-018-1976-6. Epub 2018 Jan 20.
Glutamic acid decarboxylase (GAD65) has been implicated in a number of autoimmune-associated neurologic syndromes, including autoimmune epilepsy. This study categorizes the spectrum of MRI findings in patients with a clinical diagnosis of autoimmune epilepsy and elevated serum GAD65 autoantibodies.
An institutional database search identified patients with elevated serum GAD65 antibodies and a clinical diagnosis of autoimmune epilepsy who had undergone brain MRI. Imaging studies were reviewed by three board-certified neuroradiologists and one neuroradiology fellow. Studies were evaluated for cortical/subcortical and hippocampal signal abnormality, cerebellar and cerebral volume loss, mesial temporal sclerosis, and parenchymal/leptomeningeal enhancement. The electronic medical record was reviewed for relevant clinical information and laboratory markers.
A study cohort of 19 patients was identified. The majority of patients were female (84%), with a mean age of onset of 27 years. Serum GAD65 titers ranged from 33 to 4415 nmol/L (normal < 0.02 nmol/L). The most common presentation was medically intractable, complex partial seizures with temporal lobe onset. Parenchymal atrophy was the most common imaging finding (47%), with a subset of patients demonstrating cortical/subcortical parenchymal T2 hyperintensity (37%) or abnormal hippocampal signal (26%). No patients demonstrated abnormal parenchymal/leptomeningeal enhancement.
The most common MRI finding in GAD65-associated autoimmune epilepsy is disproportionate parenchymal atrophy for age, often associated with abnormal cortical/subcortical T2 hyperintensities. Hippocampal abnormalities are seen in a minority of patients. This constellation of findings in a patient with medically intractable epilepsy should raise the possibility of GAD65 autoimmunity.
谷氨酸脱羧酶（GAD65）与多种自身免疫相关的神经系统综合征有关，包括自身免疫性癫痫。本研究对临床诊断为自身免疫性癫痫且血清GAD65自身抗体升高的患者的MRI表现谱进行分类。
通过机构数据库搜索，确定血清GAD65抗体升高且临床诊断为自身免疫性癫痫并接受过脑部MRI检查的患者。影像学研究由三名获得委员会认证的神经放射科医生和一名神经放射科住院医师进行评估。对研究进行皮质/皮质下和海马信号异常、小脑和大脑体积减少、内侧颞叶硬化以及实质/软脑膜强化的评估。查阅电子病历以获取相关临床信息和实验室指标。
确定了一个由19名患者组成的研究队列。大多数患者为女性（84%），平均发病年龄为27岁。血清GAD65滴度范围为33至4415 nmol/L（正常<0.02 nmol/L）。最常见的表现是药物难治性复杂部分性发作，起于颞叶。实质萎缩是最常见的影像学表现（47%），一部分患者表现为皮质/皮质下实质T2高信号（37%）或海马信号异常（26%）。没有患者表现出实质/软脑膜强化异常。
GAD6与自身免疫性癫痫相关的最常见MRI表现是与年龄不相称的实质萎缩，常伴有皮质/皮质下T2高信号异常。少数患者可见海马异常。在药物难治性癫痫患者中出现的这一系列表现应提高GAD65自身免疫的可能性。
