线粒体脑病--神经影像病例汇报.pptVIP

神经影像病例汇报 朱颖 2009-10-20 Case 1 2090748 男，31岁 主因“发作性视力下降，听力下降伴癫痫5年，复发表达异常、听理解异常3天”入院 入院查体： 发育差，身材偏瘦，言语欠流利，听理解力障碍，命名障碍，查体欠合作。 高级皮层功能查体不配合。 四肢腱反射未引出。 左侧Babinski（+），右侧（±） 乳酸 13.8↑（ 0.5-2 mmol/l ） （May-04，天坛）血mtDNA A3243突变阳性 Case2 631976 女，11岁 “间断抽搐伴视力下降2年，右侧肢体活动障碍1周”09-4入院 2年来2此频繁抽搐、类卒中样发作，伴视力下降，头痛、生长发育缓慢，智力落后、倒退。 查体： 身材矮小，头围小，计算力差，背部多毛，右眼内斜，拖曳步态；肌力右侧上下肢IV－，腱反射弱。 脑电图：异常 肌电图未见异常。 乳酸高 线粒体病 定义 由于遗传缺损引起线粒体代谢缺陷，导致ATP合成障碍，能量产生不足而出现的一组多系统疾病。 分类 MELAS发病机制 血管病学说 异常的线粒体沉积于软脑膜和脑内小动脉的平滑肌细胞和内皮细胞，导致脑组织缺血而致病 细胞病学说 线粒体功能障碍导致脑神经细胞能量供应不足，无氧代谢增加，乳酸酸中毒，当能量需求增高时， 即诱发卒中样发作 线粒体的氧化磷酸化异常最容易损伤枕叶 非缺血性神经血管细胞学说 神经元过度兴奋、神经元脆弱、毛细血管通透性增加和充血 MR表现 游走 皮质受累为主 顶枕颞多见 不按脑血管分布 钙质沉积 基底节等脑内神经核团 不同时期 发作期 慢性期 钙化 MRA 少见异常 DWI ADC↑血管源性水肿 ADC↓细胞毒性水肿 MRS NAA↓ Lac Fig. 1 MRI exams were realized at admission (D0), at 15 days (D15) of evolution, and for control 6 (M6) and 12 months later. Conventional FLAIR and DWI data are represented in Fig. 1. FLAIR and DWI sequences are represented at two levels; the first 2 left columns corresponding to a view at the temporal level, and the 2 right columns to the occipital level. Rows represent successively MRI exams realized at D0, D15, and M6 (MRIs at M12 were not represented as they were similar to images obtained 6 months earlier). At admission, recent left temporal lesion appeared with a hyper intensity on FLAIR sequence (1a), and ADCs were heterogeneous; elevated in anterior localization, and diminished in posterior region (1b). There were no signal abnormalities on FLAIR or DWI views in the occipital regions (2a and 2b). At D15, bilateral occipital FLAIR hyperintensities appeared (2c). ADCs increased in these regions (2d), and became homogeneously elevated in the left temporal lesion (1d). At M6, FLAIR hyperintensities diminished in the temporal lesion, replaced with gliosis (1e), and disappeared in the occipital region (2e). Lesion regression was more marked in those regions of the temporal lobe in which ADCs were previously the most elevated (white arrow). FLAIR abnorm