Functional magnetic resonance imaging of visual cortex in a patient with cerebrovascular insufficiency

We compare the findings of functional magnetic resonance imaging (MRI) of the visual cortex in a patient with moyamoya disease with other neuro-imaging techniques. Automated static perimetry demonstrated a slight depression of the left visual field in both eyes. MRI of the brain showed diffuse atrophy of the right cerebral hemisphere, sparing the occipital lobe. Single-photon emission computed tomography showed relatively preserved perfusion to the right occipital lobe. Functional MRI during visual stimulation, however, demonstrated an apparent lack of activation of the right primary visual cortex, which did not correlate with the known retinotopic map of the visual cortex. The patient seems to have had a lack of reserved ability to respond to visual stimuli with maximal autoregulatory vasodilatation in the visual cortex, even though apparent morphologic change and dense visual field defects had not been observed.