MELAS型线粒体脑肌病的MRI诊断

MRI diagnosis of mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes

目的探讨MELAS型线粒体脑肌病的MRI的表现特点。方法回顾分析10例经病理证实的MELAS型线粒体脑肌病患者的临床及MRI检查资料。结果10例患者均为多脑叶发病，5例双侧颞、枕、顶叶皮层及皮层下可见大片状长T1长T2信号影，具有一定对称性，3例右侧额叶、颞叶、枕叶大片状长T1长T2信号影，2例左侧颞叶、枕叶大片状长T1长T2信号影，病变不按血管支配区分布。FLAIR序列呈高信号，急性期病变于DWI序列呈高信号，有3例累及脑深部核团，累及豆状核2例，累及豆状核和尾状核1例，累及小脑2例，累及脑干1例，并有不同程度脑萎缩4例。增强扫描少有强化。结论MELAS型线粒体脑肌病的MRI表现有一定特征性，但最终诊断需结合临床表现和实验室检查。

Objective To investigate the characteristic of mitochdndrial encephalomyopathy with lactic acidosis and strokelike episodes（MELAS} on MRI. Method 10 patients with MELAS confirmed by pathological examination were retrospectively analyzed and undertook MRI examination. Results All the 10 patients had lesions of multiple lobes. Brain parenchymal lesions in all patients Were low intensity on TIWI and high signal intensity on T2WI. Five patients had double prefrontal lobe, parietooccipital cortex involvement , while involvement of right frontal pole, pre- frontal lobe,occipital pole were observed in 3 patients, and two patients had left prefrontal lobe, occipital cortex in- volvement. All the patients had lesions which were not in consistence with the distribution of intracranial vessels. Brain parenchymal lesions were high intensity on FLAIR and high signal intensity on DWI in acute phase. There were three patients had deep brain nucleus involvement,two had lentiform nucleus involvement, and one had lenti- form nucleus and caudate nucleus involvement. Two patients had cerebellar involvement, while involvement of brainstem was observed in 1 patients, and four patients had brain atrophy, only few was enhanced on MRI enhance- ment scanning. Conclusion MRI appearance of mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes（MELAS） have some characteristics. If we connect tightly clinical appearance,laboratory results with MRI manifestation, accuracy of diagnosis can be highly increased.