MELAS型线粒体脑肌病的多模态MRI诊断

目的：探讨MELAS型线粒体脑肌病的多模态影像学特点.方法：对11例MELAS型线粒体脑肌病患者的脑MRI、MRA、DWI及MRS影像资料进行分析.结果：MRI：MELAS病灶多位于枕顶叶大脑皮层,多发为主,多变性、游走性,与血管的走行不一致,5例海马、海马旁回受累,5例合并基底节核团受累,4例合并大脑和（或）小脑萎缩,7例增强扫描未见强化;MRA：1例病灶处动脉分支增多,6例未见异常;DWI：5例均为高和（或）稍高信号,ADC图为稍高信号2例、稍低信号2例、稍高等稍低混杂信号1例;MRS：病灶区及对侧正常区均可见升高的乳酸（Lac）双峰,病灶区与对侧正常区比较Lac及Lac/Cr均明显增高（P＜0.001）.结论：MELAS型线粒体脑肌病的多模态MRI表现有一定特异性,综合分析,可提示诊断.

Diagnosis of multimode magnetic resonance imaging in MELAS

Objective： To investigate multimode magnetic resonance finding imaging in the patients with MELAS type of mitochondrial encephalomyopathy. Methods： MRI, MRA, DWI and MRS manifestations of 11 cases with MELAS were retro- spectively analyzed. Results： In 11 cases, the lesions were mainly distributed in the cortical zones of occipital and parietal lobe, hippocampus, parahippocampal gyrus were involved in 5 cases, and basal ganglia involvement in 5 cases too. The distri- bution of the lesions was muhip]e, wandering and variable, and the location was not corresponding with the vascular supply territories. Four cases presented cerebellum and（or） cerebellar atrophy. Seven cases showed no enhancement after contrast scan- ning. In 1 of the 7 cases with MRA, there were increased arterial branches of the lesions zone, other 6 cases were normal, In 5 cases, the lesions showed hyperintensity and（or） slight hyperintensity on DWI, slight hyperintensity（2 cases） or hypointen- sity（2 cases） or mix-intensity （1 case） on ADC images. The focal lesions and relatively normal areas showed increasing Lac peak on ~H-MRS. The quantitative analysis manifested that the value of Lac and Lac/Cr were obviously increased（P〈0.001） in the focal lesions than the normal areas. Conclusion： Muhimode magnetic resonance image is relatively specific to MELAS and can make diagnosing MELAS with comprehensive analysis.