ZHU Yaxin,ZHANG Siyu,YANG Di, et al. The follow-up analysis of MR imaging in MELAS syndrome[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2016, 46(7): 503-506,512.
Abstract：Objective: To analyze the MRI features of dynamic change of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). Methods: The clinical data and imaging findings of 15 cases of MELAS patients were retrospectively analyzed. All of patients underwent MRI examinations (including T1WI, T2WI, T2FLAIR and DWI) in acute attack stage (within 30 days). Forteen cases underwent MRI scanning after the acute attack stage (between 30 days～60 days), of which 8 cases were examined on MRS. Ten cases were repeated the MRI examinations in remission stage (>60 days). The location, range, signal intensity and dynamic change of the lesions were intensively analyzed. Results: In acute attack stage (within 30 days), 46.7% (7/15) unilateral cortical or subcortical cortex were affected, 53.3% (8/15) on bilateral cortical or subcortical cortex, 4 cases on bilateral basal ganglia and 1 case on brainstem. The gray matter of all 15 cases was hypointense on T1WI, hyperintense on T2WI and isointense or hyperintense on DWI. After the acute attack stage (between 30 days and 60 days) of the 14 cases, the lesions expanded in 64.3% cases (9/14), shrinked in 71.4% cases (10/14), and new foci emerged in 42.9% cases (6/14). Lactate peak increased in the fresh lesions of 8 cases, and the Lac peak increased in the contralateral area in 2 cases, while the nitrogen-acetyl aspartic acid (NAA) peaks decreased in 6 cases. In remission stage (>60 days), the atrophy was found in 40% cases (4/10) and encephalomalacia foci were found in 40% cases. Conclusion: Transient lesions are easily referred to the cerebral cortex and subcortex in MELAS patients. MRS shows prominent increasing peak. Brain atrophy in the MELAS patients develops gradually and stroke-1ike lesions shrink with progression of the disease. Combined with clinical data, the accuracy of early diagnosis of MELAS syndrome can be improved.
