MRI
Alternate Names : Magnetic Resonance Imaging, Nuclear Magnetic Resonance (NMR) Imaging
Definition
MRI is a non-invasive procedure that uses powerful magnets and radio waves to construct pictures of the body.
Unlike conventional radiography and Computed Tomographic (CT) imaging, which make use of potentially harmful radiation (X-rays), MRI imaging is based on the magnetic properties of atoms. A powerful magnet generates a magnetic field roughly 10,000 times stronger than the natural background magnetism from the earth. A very small percentage of hydrogen atoms within a human body will align with this field.
When focused radio wave pulses are broadcast towards the aligned hydrogen atoms in tissues of interest, they will return a signal. The subtle differences in that signal from various body tissues enables MRI to differentiate organs, and potentially contrast benign and malignant tissue.
Any imaging plane (or "slice") can be projected, stored in a computer, or printed on film. MRI can easily be performed through clothing and bones. However, certain types of metal in the area of interest can cause significant errors in the reconstructed images.
Pictures & Images
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Why is the Test Performed?
An MRI can provide additional imaging information for the clinician based upon its superior tissue contrast resolution. Combined with other imaging methods, a more definitive diagnosis can be given in the work up of a patient's disease.
Sequences performed with intravenous contrast may provide additional data about the blood vessels within masses.
An MRA, or magnetic resonance angiogram, is a special type of MR that creates three-dimensional reconstructions of vessels containing flowing blood and is often utilized when conventional angiography cannot be performed due to renal failure or other contraindications.
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