线粒体脑肌病临床与影像学动态变化特点分析

摘要

Background There are certain challenges for imaging diagnosis of mitochondrial encephalomyopathy(ME).And the study of dynamic imaging data during the progression of the disease is still deficient.Objective To investigate the clinical and dynamic head CT and MRI manifestations in patients with ME,and MELAS(mitochondrial encephalomyopathy,lactic acidosis,and stroke-like episodes) syndrome in particular.Methods The clinical and dynamic cranial imaging manifestations during the 19 episodes of 9 patients with ME diagnosed in the First Affiliated Hospital of Wenzhou Medical University from 2010 to 2015 were reviewed,of which the signal changes of diffusion-weighted imaging(DWI) and apparent diffusion coefficient(ADC) during the progression of disease were observed dynamically.Results Most of the 9 cases were young males(6 cases),their clinical manifestations included seizures,stroke-like episodes,cognitive impairment,headaches or dizziness,decrease in hearing or vision,obvious muscular atrophy and so on.Nine patients were found with 23 lesions involving in the lobes of the brain.Head CT scanning found low-density lesions,and bilateral basal ganglia with high-density shadow.Head MRI scanning indicated that,the intracranial lesions had low signal intensity on T1 and opposite on T2;initially the lesions were swelling,the affected gyri had high signal intensity on DWI and low signal intensity on ADC;the adjacent subcortex was found with nebulously high signal intensity on ADC and that existed steadily for a long time;over time the signal intensity on DWI decreased slowly in gyri while that on ADC increased;in the progression of the disease,it was found that the range of partial lesions narrowed down,and there were irreversible findings including enlarged adjacent ventricle,or widened sulci and faveolate liquefaction in parenchyma when nervous tissue necrosis was involved.Head CT scanning detected that 4 cases had high-density shadow(iron deposition/calcification) in bilateral basal ganglia.Conclusion The clinical manifestations of these ME patients are complicated and various,most of them are cortex-involved.Head CT scanning can provide some information of iron deposition or calcification in nucleus.As for head MRI scanning,DWI and ADC can dynamically reflect the changing process of ME to some extent.%背景 线粒体脑肌病影像学诊断存在一定困难,目前尚缺乏针对该病疾病进展中影像学动态变化特点的研究.目的 探讨线粒体脑肌病,尤其是线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)综合征的临床特点与颅脑CT及MRI影像学动态变化特点.方法 回顾性分析温州医科大学附属第一医院2010-2015年确诊的9例线粒体脑肌病患者共19次发作时的临床特点及颅脑影像学表现,动态观察病情演变过程中相应病灶弥散加权成像(DWI)及表观弥散系数(ADC)的变化等情况.结果 9例患者中5例确诊为MELAS综合征.9例患者以年轻男性(6例)为主,临床主要表现为痫性发作、脑卒中样发作、认知功能减退、头痛或头晕、听力或视力下降、明显肌肉萎缩.9例患者共计23个病灶累及大脑各脑叶,颅脑CT检查显示病灶部位呈低密度改变,MRI检查显示病灶部位T1低信号T2高信号.病变初期以血管源性水肿为主,脑回部位DWI高信号ADC低信号,邻近皮质下出现云絮状高信号改变并持续存在,脑回部位DWI信号随时间缓慢减低,而ADC随之升高;病程中部分组织坏死,出现邻近脑室扩大或脑沟增宽、蜂窝状液化等不可逆改变.4例CT检查显示双侧基底核区高密度影(铁沉积/钙化).结论 线粒体脑肌病临床表现复杂多样,以皮质受累为主,颅脑CT检查可发现铁沉积/钙化,而颅脑MRI检查中病灶部位DWI和ADC变化能够在一定程度上动态反映线粒体脑肌病的疾病演变特点.