MELAS综合征的MRI诊断  

The MRI findings of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes

作　　者：王柳仙 席一斌[1] 田萍[1] 李陈[1] 印弘[1] 

机构地区：[1]第四军医大学西京医院放射科,陕西西安710032

出　　处：《实用放射学杂志》2016年第4期510-513,共4页Journal of Practical Radiology

摘　　要：目的 回顾性分析线粒体脑肌病伴高乳酸血症和卒中样发作（MELAS）综合征的MR表现特点，提高对MELAS综合征早期诊断的能力。方法 收集经临床诊断的MELAS综合征共16例，均由肌肉病理活检证实。所有患者均行MR平扫，其中3例行ASL扫描，15例行MRA检查，14例行DWI扫描，3例行MRS扫描，并回顾性综合分析其影像学资料。结果 MRI检查发现，本组MELAS综合征多表现为大脑半球各叶大小不等片状病灶，病变多位于大脑半球后部脑皮质区，向皮层下的白质蔓延，病灶的分布与脑血供分布不一致；自旋回波T1WI呈低信号、T2WI呈高信号，FLAIR呈高信号；DWI呈高信号；3例行MRS分析提示病灶区典型乳酸峰；其中1例MRA检查提示病灶区分支血管增多，1例分支血管减少；3例行ASL检查提示病灶区高灌注。16例中4例随访病灶具有游走性、多变性、此起彼伏等表现，旧病灶有脑萎缩、脑软化等表现。16例行肌组织活检见破碎样红纤维（RRF）；电镜见线粒体体积增大、数量增多，肌纤维粗细不等，少数萎缩变细。3例行线粒体基因测序发现线粒体DNA（mtDNA）A3243G点突变。结论 DWI、MRS及ASL在MELAS综合征诊断中具有良好的价值。Objective To analyze retrospectively the MR features of MELAS patients, in order to improve the early diagnosis of MEL＇AS. Methods MR data of 16 MELAS patients confirmed by clinical diagnose and muscle biopsy were retrospectively analyzed. MR features of plain scan（n=16）, ASL（n=3）, MRA（n=15）, DWI（n=14） and MRS（n=3） were analyzed. Results MRI data demonstrated brain lesions mainly distributed in posterior cerebral hemisphere extending to subcortical area, which was not consistent with the vascular supply territories. The lesions were observed as low signal on Spin-echo sequence of TIWI, while high signal on T2 WI, FLAIR and DWI. The focal lesions showed increasing Lac peak on MRS. Fifteen of 16 patients underwent MRA and one showed increased arterial branches in lesion zones. Three patients had ASL scanning demonstrating high irrigation in lesion zones which would wander once relapsed. Meanwhile, old lesions showed encephalatrophy and cerebromalacia. All patients＇ muscle biopsy pathology showed ragged red muscle fibers. Under electron-microscopic, bioblasts were bigger and more than average level and muscle fibers atrophied. Mitochondrial DNA sequence of 3 patients showed mtDNA A3243G transgenation. Conclusion The DWI, MRS and ASL sequences show good ability in MELAS diagnosis and differential diagnosis.

关 键 词：MELAS综合征 磁共振成像 动脉自旋标记 

分 类 号：R742[医药卫生—神经病学与精神病学] R445.2[医药卫生—临床医学]