Medical Imaging
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Diffusion MRI (or dMRI ) is a Magnetic Resonance Imaging (MRI) method which came into existence in the mid-1980s. [ 1 ] [ 2 ] [ 3 ] It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues , in vivo and non-invasively. Molecular diffusion in tissues is not free, reflecting interactions of molecules with many obstacles, such as macromolecules, fibers, membranes, etc. Water molecules are thus used as a probe that can reveal microscopic details about tissue architecture, either normal or in a diseased state. The first diffusion MRI images of the normal and diseased brain were made public in 1985. [ 4 ] [ 5 ] During the last 25 years, diffusion MRI has been extraordinarily successful. Its main clinical domain of application has been neurological disorders, especially for the management of patients with acute stroke.
Diffusion MRI - Wikipedia, the free encyclopedia
Magnetic resonance imaging - Wikipedia, the free encyclopedia
Para-sagittal MRI of the head, with aliasing artifacts (nose and forehead appear at the back of the head) Magnetic resonance imaging ( MRI ), nuclear magnetic resonance imaging ( NMRI ), or magnetic resonance tomography ( MRT ) is a medical imaging technique used in radiology to visualize detailed internal structures. MRI makes use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body. An MRI machine uses a powerful magnetic field to align the magnetization of some atomic nuclei in the body, and radio frequency fields to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by the scanner—and this information is recorded to construct an image of the scanned area of the body. [ 1 ] :36 Magnetic field gradients cause nuclei at different locations to rotate at different speeds.
Epileptic spike and wave discharges monitored with EEG Electroencephalography ( EEG ) is the recording of electrical activity along the scalp . EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain . [ 2 ] In clinical contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, usually 20–40 minutes, as recorded from multiple electrodes placed on the scalp .
Electroencephalography - Wikipedia, the free encyclopedia
Positron emission tomography - Wikipedia, the free encyclopedia
PET/CT-System with 16-slice CT; the ceiling mounted device is an injection pump for CT contrast agent Positron emission tomography ( PET ) [ 1 ] is a 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 (tracer), which is introduced into the body on a biologically active molecule. Three-dimensional images of tracer concentration within the body are then constructed by computer analysis. In modern scanners, three dimensional imaging is often accomplished with the aid of a CT X-ray scan performed on the patient during the same session, in the same machine. If the biologically active molecule chosen for PET is FDG , an analogue of glucose , the concentrations of tracer imaged then give tissue metabolic activity, in terms of regional glucose uptake.
Single photon emission computed tomography - Wikipedia, the free encyclopedia
Single-photon emission computed tomography (SPECT, or less commonly, SPET) is a nuclear medicine tomographic [ 1 ] 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. This information is typically presented as cross-sectional slices through the patient, but can be freely reformatted or manipulated as required. The basic technique requires injection of a gamma-emitting radioisotope (called radionuclide ) into the bloodstream of the patient. On occasion, the radioisotope is a simple soluble dissolved ion, such as a radioisotope of gallium(III), which happens to also have chemical properties that allow it to be concentrated in ways of medical interest for disease detection.
Functional magnetic resonance imaging - Wikipedia, the free encyclopedia
Researcher checking fMRI images Functional magnetic resonance imaging or functional MRI ( fMRI ) is an MRI procedure that measures brain activity by detecting associated changes in blood flow. [ 1 ] The primary form of fMRI uses the blood-oxygen-level-dependent (BOLD) contrast, [ 2 ] discovered by Seiji Ogawa . This is a type of specialized brain and body scan used to map neural activity in the brain or spinal cord of humans or animals by imaging the change in blood flow ( hemodynamic response ) related to energy use by brain cells. [ 3 ] Since the early 1990s, fMRI has come to dominate brain mapping research because it does not require people to undergo shots, surgery, or to ingest substances, or be exposed to radiation. [ 4 ] The procedure is similar to MRI but uses the change in magnetization between oxygen-rich and oxygen-poor blood as its basic measure.