Distinguishing ischemic stroke from the stroke-like lesions of MELAS using apparent diffusion coefficient mapping.

We report two patients with migraine, acute visual field defects and other neurological symptoms who were found to have high T(2) signal and FLAIR abnormalities on brain MRI in temporal and parieto-occipital regions. In these patients, the apparent diffusion coefficient (ADC) of their lesions was increased, distinguishing these lesions from those of ischemic stroke. Both were ultimately diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). We conclude that conventional MRI when used with diffusion-weighted MR imaging may be invaluable in detecting mitochondrial-related CNS dysfunction.