Dynamic evolution of brain magnetic resonance imaging findings in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome

Abstract

Objective To analyze the dynamic evolution of brain MRI in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. Methods A retrospective study was performed on 58 MELAS cases with pathologically and （or） molecularly confirmed diagnosis. MRI were repeated within 60 days after the onset of stroke-like episodes (SLE) and the evolution changes of cerebral lesions were accessed. Brain atrophy index (BAI) was calculated in the remission stage from 31 patients with MELAS, and the correlation between BAI, age and disease duration was analyzed. Results The proportion of lesions expansion, migration and shrink within 30 days after the onset of SLE was 64.1%(25/39), 10.2%(4/39), 17.9%(7/39), respectively, and 13%(3/23), 21.7%(5/23),56.5%(13/23), between 30—60 days after the onset of SLE respectively.In the recovery stage of SLE, the BAI in 31 patients with MELAS was 15.2%±2.8%. The correlation coefficient between BAI and the age, total disease course and duration of encephalopathy was 0.329(P=0.043)，0.405(P=0.012) and 0.649(P=0.000). Conclusions Brain atrophy in the studied MELAS patients gradually develops and stroke-like lesions shrink with progression of the disease. However, the migration of lesions is persistent. Key words: MELAS syndrome; Magnetic resonance imaging; Atrophy; Brain