Tc-99m Exametazime Brain Imaging

Highly lipophilic molecules (such as exametazime) will penetrate the protective blood brain barrier and be taken up in the brain tissues.  Since uptake will be proportional to regional blood flow, the amount of tracer deposited will be indicative of how much blood flow reaches a particular area.  In this example, an overactive seizure focus shows a greater amount of tracer uptake due to the increased metabolic and blood flow demand.