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The opposite of an indication is a contraindication, [4] a reason to withhold a certain medical treatment because the risks of treatment clearly outweigh the benefits. In the United States, indications for prescription drugs are approved by the FDA. Indications are included in the Indications and Usage section of the Prescribing Information.
In the example shown here, the gradient echo image shows the region of likely cytotoxic edema whereas the SW image shows the likely localization of the stroke and the vascular territory affected (data acquired at 1.5 T). The bright region in the gradient echo weighted image shows the area affected in this acute stroke example.
However, greater capital costs and effects of off-resonance artefact on image quality mean that many studies are routinely performed at 1.5T. [29] Imaging at 7T field strength is a growing area of research, but is not widely available. [30] Current manufacturers of cardiac-capable MRI scanners include Philips, Siemens, Hitachi, Toshiba, GE.
MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from computed tomography (CT) and positron emission tomography (PET) scans. MRI is a medical application of nuclear magnetic resonance (NMR) which can also be used for imaging in other NMR applications, such as NMR spectroscopy. [1] MRI is widely used in ...
Modern 3 Tesla clinical MRI scanner.. Magnetic resonance imaging (MRI) is a medical imaging technique mostly used in radiology and nuclear medicine in order to investigate the anatomy and physiology of the body, and to detect pathologies including tumors, inflammation, neurological conditions such as stroke, disorders of muscles and joints, and abnormalities in the heart and blood vessels ...
For example, because MRI has only been in use since the early 1980s, there are no known long-term effects of exposure to strong static fields (this is the subject of some debate; see 'Safety' in MRI) and therefore there is no limit to the number of scans to which an individual can be subjected, in contrast with X-ray and CT. However, there are ...
The brightness is weighted by the fractional anisotropy which is a scalar measure of the degree of anisotropy in a given voxel. Mean diffusivity (MD) or trace is a scalar measure of the total diffusion within a voxel. These measures are commonly used clinically to localize white matter lesions that do not show up on other forms of clinical MRI ...
It does not need gadolinium contrast. [23] Dynamic contrast enhanced: DCE: Measures changes over time in the shortening of the spin–lattice relaxation (T1) induced by a gadolinium contrast bolus. [24] Faster Gd contrast uptake along with other features is suggestive of malignancy (pictured). [25] Functional MRI (fMRI) Blood-oxygen-level ...