Functional imaging (or functional medical imaging), is a method of detecting or measuring changes in metabolism, blood flow, regional chemical composition, and absorption.
As opposed to structural imaging, functional imaging centers on revealing physiological activities within a certain tissue or organ by employing medical image modalities that very often use tracers or probes to reflect spatial distribution of them within the body. These tracers often are proportional to some chemical compounds, like glucose, within the body. To achieve this, isotopes are used because they have similar chemical and biological characteristics. By appropriate proportionality, the doctors or radiologists can determine the real intensity of certain substance within the body to evalutate the risk or danger of developing some diseases.
- Positron emission tomography (PET)
- F-18 for Glucose metabolism
- O-15 as a flow tracer
- Single photon emission computed tomography (SPECT)
- Functional magnetic resonance imaging (fMRI)