Functional imaging (or physiological imaging) is a
medical imaging technique of detecting or measuring changes in
metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...
, blood flow, regional chemical composition, and absorption.
As opposed to structural imaging, functional imaging centers on revealing
physiological
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemica ...
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 are often
analogous 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
nuclear medicine physicians can determine the real intensity of certain substance within the body to evaluate the risk or danger of developing some diseases.
Modalities
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Positron emission tomography
Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, ...
(PET)
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Fludeoxyglucose for Glucose metabolism
** O-15 as a flow tracer
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Single-photon emission computed tomography
Single-photon emission computed tomography (SPECT, or less commonly, SPET) is a nuclear medicine tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera (that is, ...
(SPECT)
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Computed tomography (CT) perfusion imaging
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Functional magnetic resonance imaging (fMRI)
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BOLD
In typography, emphasis is the strengthening of words in a text with a font in a different style from the rest of the text, to highlight them. It is the equivalent of prosody stress in speech.
Methods and use
The most common methods in ...
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Diffusion MRI
Diffusion-weighted magnetic resonance imaging (DWI or DW-MRI) is the use of specific MRI sequences as well as software that generates images from the resulting data that uses the diffusion of water molecules to generate contrast in MR images. It ...
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Perfusion (blood flow)
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Arterial spin labeling MRI
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Blood volume
Blood volume (volemia) is the volume of blood (blood cells and plasma) in the circulatory system of any individual.
Humans
A typical adult has a blood volume of approximately 5 liters, with females and males having approximately the same blood pe ...
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Hyperpolarized carbon-13 MRI
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Functional photoacoustic microscopy (fPAM)
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Magnetic particle imaging Magnetic particle imaging (MPI) is an emerging non-invasive tomographic technique that directly detects superparamagnetic nanoparticle tracers. The technology has potential applications in diagnostic imaging and material science. Currently, it ...
(MPI)
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Optical imaging
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Near-infrared spectroscopy
Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from 780 nm to 2500 nm). Typical applications include medical and physiological diagnostics and research inc ...
(NIRS)
See also
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Biomedical engineering
Biomedical engineering (BME) or medical engineering is the application of engineering principles and design concepts to medicine and biology for healthcare purposes (e.g., diagnostic or therapeutic). BME is also traditionally logical sciences ...
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Medical imaging
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PET-CT
Positron emission tomography–computed tomography (better known as PET-CT or PET/CT) is a nuclear medicine technique which combines, in a single gantry, a positron emission tomography (PET) scanner and an x-ray computed tomography (CT) scann ...
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Radiology
Radiology ( ) is the medical discipline that uses medical imaging to diagnose diseases and guide their treatment, within the bodies of humans and other animals. It began with radiography (which is why its name has a root referring to radiati ...
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Functional neuroimaging
Functional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions. It is primarily used a ...
References
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External links
Scholarpedia Functional imaging Medical imaging