Reversible cerebral vasoconstriction syndromes (RCVS) typically affect the bilateral medium-sized intracerebral arteries and their branches. We describe a woman with RCVS restricted to the ipsilateral hemisphere after carotid endarterectomy. Serial CT angiography proved useful in documenting vasoconstriction. Perfusion MR imaging showed hypoperfusion in the deep watershed regions of the ipsilateral cerebral arteries but relatively normal perfusion in superficial cortical regions. Diffusion MR imaging showed progressive borderzone infarcts. These novel imaging findings provide insights into the pathophysiology of stroke in RCVS.