Brain scan
From Radipedia
Tc99m HMPAO
- Lipophilic agent crosses BBB, rapid intracellular uptake in proportion to blood flow, fixed intracellularly
- Provides snapshot of blood flow at time of injection
F18-FDG PET
Increased activity can also be seen with sensory/motor stimulation
Epilepsy
- Hypometabolic on interictal scan
- Hypermetabolic on ictal scan
Alzheimer's Disease - decreased uptake in the bilateral posterior parital regions
Pick's Disease - decreased uptake in the bilateral anterior frontal and anterior temporal regions
Multiinfarct Dementia - multiple asymmetric defects
Huntington's Disease - decreased uptake in basal ganglia
Tumor
- Can also be used to differentiate brain neoplasm and infection in AIDS patients for example *FDG-PET, TI210 and Tc99m all demonstrate increased activity with malignancy and low uptake with infection
- Can differentiate residual tumor (hot) and radiation necrosis (cold)
Parkinson's Disease
- Normal on PET
- Certain agents developed from the DOPA pathway (tyrosine) do show increased activity
