线粒体脑肌病伴高乳酸血症和卒中样发作综合征的影像学特征及动态演变

摘要

Objective To investigate the features and dynamic evolution of imaging in mitochondrial encephalomy-opathy with lactic acidosis and stroke-like episodes ( MELAS) syndrome.Methods The data of 21 cases of MELAS syn-drome diagnosed by muscle biopsy in our hospital from January 2011 to February 2016 were collected ,and the neuroimaging of CT,MRI,enhanced MRI ,MRA and MRS were retrospectively analyzed .Results 8 cases showed bilateral basal ganglia calcification symmetry in 19 patients who underwent head CT scan .The abnormal areas showed low signal intensity on T1 WI,high signal intensity on T 2 WI and FLAIR,high or equal signal intensity on DWI ,high or low signal intensity on ADC in stroke-like episodes;the NAA peak was decreased and lactate peak was significantly increased on MRS .19 cases (90.5%) were involved in 2 and more than 2 lobes,and the most frequently involved parts of the lesion were occipital ,tem-poral and parietal lobe .The lesions were lamellar necrosis ,and the distribution was not in accordance with the control region of the cerebral vessels .Dynamic observation revealed that the lesions were reversible ,migratory and progressive .Conclusion MELAS syndrome had complex clinical manifestations ,and the neuroimaging had certain characteristics and important di-agnostic value .Fully understanding these characteristics will help to make early diagnosis and treatment , also reduce the misdiagnosis .%目的：探讨线粒体脑肌病伴高乳酸血症和卒中样发作（ MELAS）综合征的影像学特点及其动态演变过程。方法收集2011年1月－2016年2月我院经肌肉病理确诊的21例MELAS综合征的资料，对他们的头部CT、MRI、增强MRI、MRA和MRS表现进行回顾性分析。结果19例患者行头部CT，其中8例显示双侧基底节区对称性钙化。卒中样发作急性期头部磁共振主要表现为T1 WI低信号、T2 WI和FLAIR高信号，DWI高信号或等信号，ADC高信号或低信号；增强MRI未见明显强化或线状强化，MRA未见明显异常，MRS可见N-乙酰天门冬氨酸峰（NAA）下降、乳酸峰（Lac）明显升高。19例（90．5％）病灶累及2个及2个以上脑叶，最常累及的部位是枕叶、颞叶和顶叶。病灶呈层状坏死，分布不符合脑血管的支配区域，动态观察具有“可逆性”、“游走性”和“进展性”。结论 MELAS综合征临床表现复杂，神经影像学具有一定的特征性，具有重要诊断价值。充分认识这些特征，有助于早期诊治、减少误诊。