桥本脑病的磁共振成像表现及其病理机制

Magnetic Resonance Imaging Features and Their Pathological Mechanisms of Hashimoto's Encephalopathy

目的分析桥本脑病(HE)的常规及功能磁共振成像(MRI)表现,并基于功能MRI表现初步探讨其病理机制。方法回顾性分析2010年1月至2017年4月30例HE患者的临床资料、磁共振常规及功能影像,其中15例患者行增强MRI,16例行弥散加权成像(DWI),8例行磁共振血管成像,2例行氢质子波谱成像,1例同时行动脉自旋标记灌注成像和弥散张量成像,7例有临床和MRI随访资料。观察病变的分布、信号及功能影像特点。结果颅脑MRI检查正常者8例(8/30),异常者22例(22/30);异常病例中,脑小血管病样改变9例(9/22),非特异性改变13例(13/22),非特异性改变以大脑半球白质区(12/13)、多发(11/13)病灶为主,少数病例合并小脑萎缩(2/13);病变为局灶性或融合性的斑点状或小片状长或等T1长T2信号,液体衰减反转恢复序列呈高信号,增强后大多数不强化(12/15)。7例患者(7/16)出现DWI异常,其中3例急性发病者DWI呈高信号,表观弥散系数值减低,4例亚急性或慢性发病者DWI呈高信号,表观弥散系数值升高。3例颅内动脉局限性狭窄(3/8)。2例氢质子波谱成像中,病变区氮-乙酰天门冬氨酸峰明显降低,胆碱峰升高,出现乳酸峰或脂质峰。7例随访资料的患者中,3例前后无变化,4例出现变化,其中2例病灶软化(2/4),1例出现复发缓解表现(1/4),1例首次MRI阴性表现、随后出现快速进展的脑萎缩(1/4)。结论常规MRI结合功能成像能从多角度反应HE的影像特点,HE常规MRI主要特点为累及白质为主的多灶融合性病变,多无强化,功能成像则提示HE急慢性期缺血及脱髓鞘改变的病理特点,结合临床资料可与其他疾病进行鉴别。

Objective To analyze the routine and functional magnetic resonance imaging(MRI)features and their potential pathological mechanisms of Hashimoto’s encephalopathy(HE).Methods The clinical data and routine and functional MRI images of 30 HE patients who were treated in our center from January 2010 to April 2017 were retrospectively reviewed.Among them,15 patients were examined with contrast-enhanced MRI,16 with diffusion-weighed imaging(DWI),8 with magnetic resonance angiography,2 with magnetic resonance spectroscopy,and 1 with both arterial spin labeled perfusion imaging and diffusion tensor imaging.Seven patients had consecutive clinical and imaging data.The distribution,MRI signals,and functional MRI features of HE were analyzed.Results Among 30 HE patients,routine MRI showed negative results in 8 cases and abnormal findings in 22 cases.Among 22 abnormal cases,9 were characterized by small cerebral vascular disease and 13 had non-specific abnormalities;of these 13 cases,12 had lesions mainly located at the supratentorial white matter,11 had multiple lesions,and 2 had lesions complicated with cerebellum atrophy.The lesions were focal or confluent,punctate or small patchy,showing abnormal signal intensity with iso-or hypo-intensity on T1-weighed imaging,hyper-intensity on both T2-weighed imaging and fluid-attenuated inversion recovery.Most of the lesions had no enhancement(12/15).Among 7 cases with abnormalities on DWI,hyper-intensity on DWI and hypo-intensity on apparent diffusion coefficient were seen in 3 sudden acute cases and hyper-intensity on DWI and increased apparent diffusion coefficient value in 4 sub-acute or slow onset cases.Three cases showed localized intracranial artery stenosis.In 2 cases,magnetic resonance spectroscopy revealed significant lower N-acetylaspartate peak,higher choline peak,and visible lactate peak or lipid peak.Of 7 cases with follow-up data,3 cases had no change,4 cases had changes including softening lesions(2/4),remitted and relapsed lesions(1/4),and rapid progression of brain atrophy with negative finding on the initial MRI(1/4).Conclusions Routine MRI combined with functional imaging can show the features of HE from different perspectives.Routine MRI shows multifocal or confluent lesions in the white matter,mostly without enhancement,while functional imaging may reveal pathological characteristics of different phases of acute or chronic ischemia and demyelinating changes of HE.Combined with clinical data,MRI can differentiate HE from other diseases based on routine and functional MRI appearances.