title: Serial diffusion-weighted imaging in MELAS.
abstract: Clinical features of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) resemble those of cerebral infarcts, but the pathogenesis of infarct-like lesions is not fully understood. To characterise these infarct-like lesions, we studied two patients with MELAS using diffusion-weighted (DWI) MRI before and after stroke-like episodes and measured the apparent diffusion coefficient (ADC) in the new infarct-like lesions. These gave high signal on DWI and had much higher ADC than normal-appearing regions. The ADC remained high even 30 days after a stroke-like episode then decreased in lesions, with or without abnormality as shown by conventional MRI. We speculate that early elevation of ADC in the acute or subacute phase reflects vasogenic rather than cytotoxic edema. The ADC of the lesions, which disappeared almost completely with clinical improvement, returned to normal levels, which may reflect tissue recovery without severe damage. To our knowledge, this is the first study of DWI in MELAS.
authors.affiliation: Third Department of Internal Medicine, Hiroshima University School of Medicine, Japan. ohshitat@mcai.med.hiroshima-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Ohshita
authors.forename: M
authors.initials: M
authors.lastname: Oka
authors.forename: Y
authors.initials: Y
authors.lastname: Imon
authors.forename: C
authors.initials: C
authors.lastname: Watanabe
authors.forename: S
authors.initials: S
authors.lastname: Katayama
authors.forename: S
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: T
authors.initials: T
authors.lastname: Kajima
authors.forename: Y
authors.initials: Y
authors.lastname: Mimori
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology*; D004272:DNA, Mitochondrial / Q000235:genetics; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood / Q000134:cerebrospinal fluid; D017241:MELAS Syndrome / Q000175:diagnosis* / Q000235:genetics; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000201:enzymology / Q000473:pathology; D019289:Pyruvic Acid / Q000097:blood / Q000134:cerebrospinal fluid; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D004272:DNA, Mitochondrial; D019344:Lactic Acid; D019289:Pyruvic Acid; D013385:Succinate Dehydrogenase