Moyamoya disease (female, 6yrs)

Imaging shows abnormal termination of the terminal ICA's with abnormal MCA's and ACA's which are of a pin hole calibre. There is extensive proliferation of collateral vessels around the skull base consistent with Moyamoya. There are dilated perivascular spaces bilaterally. There is nonspecific high FLAIR signal intensity in the white matter in the left frontal lobe which is rather nonspecific. There are no infarcts or obvious hemispheric atrophy in keeping with chronic hypoperfusion. Areas of white matter hyperintensity which may be in keeping with areas of immature myelination. There are extensive enlarged perivascular spaces especially along the medullary veins.