Functional imaging is a method of detecting or measuring changes in metabolism

Metabolism

Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

, 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 s 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 evaluate the risk or danger of developing some diseases.

Modalities

• Positron emission tomography
  Positron emission tomography
  Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
  
   (PET)
  • F-18 for Glucose metabolism
  • O-15 as a flow tracer
• Single photon emission computed tomography
  Single photon emission computed tomography
  Single-photon emission computed tomography is a nuclear medicine tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera. However, it is able to provide true 3D information...
  
   (SPECT)
• Computed tomography (CT) perfusion imaging
• Functional magnetic resonance imaging
  Functional magnetic resonance imaging
  Functional magnetic resonance imaging or functional MRI is a type of specialized MRI scan used to measure the hemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. It is one of the most recently developed forms of neuroimaging...
  
   (fMRI)
  • BOLD
  • Diffusion MRI
    Diffusion MRI
    Diffusion MRI is a magnetic resonance imaging method that produces in vivo images of biological tissues weighted with the local microstructural characteristics of water diffusion, which is capable of showing connections between brain regions...
    
    
  • Perfusion (blood flow)
  • Arterial spin labeling MRI
  • Blood volume
• Functional photoacoustic microscopy (fPAM)
• Magnetic particle imaging
  Magnetic Particle Imaging
  Magnetic particle imaging is a tomographic imaging technique that measures the magnetic fields generated by magnetic particles in a tracer. Researchers at Philips Research have used the technique to achieve resolutions finer than one millimeter. Magnetic Particle Imaging has potential applications...
  
   (MPI)
• Optical imaging
  Optical imaging
  Optical imaging is an imaging technique.Optics usually describes the behavior of visible, ultraviolet, and infrared light used in imaging.Because light is an electromagnetic wave, similar phenomena occur in X-rays, microwaves, radio waves. Chemical imaging or molecular imaging involves inference...
  
  
  • Near infrared specroscopy (NIRS)

External links

• Scholarpedia Functional imaging