Cortical thickening of bilateral occipital lobes with predominant involvement at a parasagittal location, slightly more on the left, associated with T1 hypointense, T2 / FLAIR hyperintense signal, and minimal adjacent subcortical involvement. These aforementioned areas have high DWI signals but only small foci have low ADC signals, which are suggestive of acute infarcts. There are also foci of high DWI signals scattered at bilateral cerebellar hemispheres and right globus pallidus; some with corresponding low ADC signals. Susceptibility artifact at basal ganglia is in keeping with the calcifications noted in CT.
No grey matter heterotopia. Anterior and posterior cerebral circulations are normal. No aneurysm or arteriovenous malformation.
Sampling on MR spectroscopy demonstrates elevated lactate peak in otherwise normal-appearing brain parenchyma.
Summary:
Overall findings could represent mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). Suggest clinical correlation (eg: family history / maternal inheritance, CSF results / molecular genetic testing). Less likely differentials: other mitochondrial disorders.