What does PET primarily measure?

What does PET primarily measure?

• A. Brain metabolism
• B. Brain structure
• C. Brain activity
• D. Brain connectivity

Answer: (A)

PET primarily measures metabolic activity in brain tissue. A radiotracer like fluorodeoxyglucose is injected and behaves like glucose, so regions with higher metabolic demand take up more tracer. The PET signal therefore reflects energy use rather than the speed of neural firing itself. This sets it apart from brain structure imaging (MRI/CT), which maps anatomy, and from methods that track real-time activity (fMRI or EEG) or connectivity (how regions interact). In practice, PET highlights metabolic patterns across the brain, useful for identifying areas of altered metabolism in health and disease, such as hypometabolism in certain regions in Alzheimer's disease.

PET primarily measures metabolic activity in brain tissue. A radiotracer like fluorodeoxyglucose is injected and behaves like glucose, so regions with higher metabolic demand take up more tracer. The PET signal therefore reflects energy use rather than the speed of neural firing itself. This sets it apart from brain structure imaging (MRI/CT), which maps anatomy, and from methods that track real-time activity (fMRI or EEG) or connectivity (how regions interact). In practice, PET highlights metabolic patterns across the brain, useful for identifying areas of altered metabolism in health and disease, such as hypometabolism in certain regions in Alzheimer's disease.