FIG 1. Images obtained in an 83-year-old man with a minor, completed stroke. A, Pretreatment right carotid angiogram shows severe internal carotid artery stenosis at its origin (arrow), with delayed filling of the distal part of the artery. B, Pretreatment FLAIR image shows small ischemic lesions in the right posterior watershed area. C, Pretreatment ¹²³I-IMP SPECT scan in the resting state shows severely decreased perfusion in the right cerebral hemisphere with an asymmetry index of 50.7%. D, Pretreatment SPECT scan obtained with an ACZ challenge shows an impaired cerebrovascular reserve of 11.1% in the right cerebral hemisphere.