The "hot stroke" and transient vascular occlusions.

Two patients with left middle cerebral artery (MCA) distribution infarctions fulfilled the "hot stroke" criteria on sequential 99m Tc pertechnetate flow and static gamma camera studies. The radioisotopic finding of a paradoxical relative increased flow to the affected hemisphere correlated with serial angiography showing multiple MCA branch occlusions becoming patent with a vascular blush and early venous drainage. The angiographical finding of transient vascular occlusions suggests embolism. Using the present cases together with prior observations, some transient vascular occlusions can be diagnosed by finding an increase in relative radioisotopic flow to the involved hemisphere within a few days to weeks of the infarction. This finding should launch a search for a possible embolic source.