Figure 4.

Brain single-photon emission computedtomography images in a 74-year-old man with symptomaticright internal carotid artery (ICA) stenosis(95%) exhibiting hyperperfusion syndrome 5 daysafter carotid endarterectomy (CEA). Preoperativelate/early ¹²³I-IMZ images (first column from the left)show elevation of the values in the right cerebralcortex when compared with those in the left cerebralcortex. Preoperative early ¹²³I-IMZ images (secondcolumn from the left) show reduction of radioactivecounts in the right cerebral cortex when comparedwith those in the left cerebral cortex. ¹²³I-IMP imagesobtained immediately after surgery (second columnfrom the right) show a considerable increase in radioactivecounts in the right cerebral cortex when comparedwith those in the left cerebral cortex. ¹²³I-IMPimages on the third postoperative day (first columnfrom the right) show further increase in radioactivecounts in the right cerebral cortex compared with ¹²³I-IMPimages immediately after surgery.