Presentation
Right hemifield visual loss. Bumps into objects on the right side. Right homonymous hemianopia.
Patient Data
There is a gyriform area of restricted diffusion in the left occipital lobe with corresponding hypointensity on ADC. It involves the medial and lateral occipitotemporal gyrus, lingual gyrus and the cuneus. It shows hypointense signal on T1, hyperintense on T2/FLAIR and homogenous parenchyma enhancement on T1+C. No evidence of hemorrhage on GRE. The intervening sulci are intact and there is no mass effect to suggest edema. There is no volume loss.
A small 16 x 12 mm chronic infarct is also noted in the left posterior parietal lobe adjacent the occipital horn of the ipsilateral lateral ventricle.
Appearances are consistent with subacute infarct in the left occipital lobe (PCA territory).
Chronic infarct in the left posterior parietal lobe.
Few discrete areas of T2 and FLAIR hyperintensity are seen scattered in the suprasellar white matter. Small vessel chronic ischemic changes in the supratentorial white matter.
Case Discussion
MRI features of subacute ischemic stroke are classically depicted in this patient.
Low signal intensity on ADC, hyperintensity on DWI, high signal on T2/FLAIR and low signal on T1W sequences and parenchymal enhancement are findings pointing to subacute ischemic stroke.
Homonymous hemianopsia is visual field loss on the same side of both eyes. This is because the left cerebral hemisphere has visual pathways for the right hemifield of both eyes and the right cerebral hemisphere has visual pathways for the left hemifield of both eyes. A left PCA infarct as in this patient resulted in infarction of the occipital lobes which contains the left optic radiations hence a contralateral (right-sided) homonymous hemianopsia.