多模态磁共振成像对儿童线粒体脑肌病综合征的鉴别诊断价值

Differential diagnosis value of multimode magnetic resonance imaging in children with MELAS syndrome

目的分析儿童线粒体脑肌病(MELAS)综合征的多模态影像学特点,探讨功能成像技术的鉴别诊断价值。方法回顾性分析8例经过临床、基因检测证实的MELAS患儿的完整磁共振成像(MRI)资料,包括脑MRI平扫、增强、磁共振血管成像(MRA)、扩散加权成像(DWI)、波谱成像(MRS)、动脉自旋标记灌注成像(ASL)。结果病变主要分布于双侧枕顶叶脑皮质或皮质下区域,病灶在T1WI上呈低信号,在T2WI上呈高信号,在急性期DWI上呈等或高信号,ADC图呈现低或高信号,增强扫描呈脑回样强化或不强化。5例双侧病变,3例表现为对称性,3例复查发现,额、顶叶出现新发病变,原发病灶萎缩改变,呈多变性、游走性。2例MRA显示双侧大脑中动脉分支增多,其余未见明显异常。4例经ASL检查,急性期病变呈高灌注,MRS均在病灶区及正常区均可见升高的乳酸双峰。结论儿童MELAS综合征容易误诊,脑功能影像具有特征性,多模态MRI对儿童MELAS综合征的早期鉴别诊断有重要价值。

Objective To analyze the multimodal imaging features of children with MELAS type of mitochondrial encephalomyopathy and to explore the value of differential diagnostic functional imaging technology.Methods The complete data of MRI were retrospectively analyzed in 8 children with MELAS syndrome which confirmed by clinical and gene diagnosis.all of them underwent MRI(including plain,enhanced,MRA,DWI,MRS,ASL).Results Lesions mainly distributed in the cortex or subcortical areas of bilateral occipital parietal lobes.All lesions showed hypointense on T1WI and hyperintense on T2WI.In the acute phase of DWI,the lesions showed hyperintense or isointense,and ADC images could show hypointense and hyperintense,the enhanced scan showed gyrus-like enhancement or non-enhancement.Five cases with bilateral lesions,3 cases with symmetry,3 cases with new lesions was founded in frontal and parietal lobes by reviewing and brain atrophy in the primary lesions,the lesions was wandering and variable.Two cases had increased branches of bilateral middle cerebral artery,the other had no obvious abnormalities on MRA.Four cases were examined by ASL showed hyperperfusion in acute stage,the double peaks of lactic acid were found in both lesions and normal areas on MRS.Conclusion Children with MELAS syndrome are easy to be misdiagnosed,the functional imaging are characteristic.Multimodal MRI has great value on differential diagnosis of children with MELAS syndrome.