Cortical perfusion has not yet been extensively studied in RCVS; at time of writing, only two case reports have been published. Rosenbloom and Singhal reported a case of RCVS induced by carotid endarterectomy following a frontal lobe ischaemic stroke. Perfusion MRI showed unilateral hypo-perfusion, mainly affecting internal watershed areas with superficial cortical regions being relatively spared. In a second study, ASL-MRI was performed on a 50-year-old man with RCVS who presented with severe recurrent headaches and neurological deficits (localising to the right hemisphere). ASL-MRI demonstrated significant hypo-perfusion in the right parieto-occipital lobe, but no infarct was seen on diffusion imaging. At 12 weeks, there was complete resolution of cerebral vasoconstriction on angiography and normal perfusion findings on ASL-MRI.