MRA: The magnetic resonance angiogram, or MRA, is a noninvasive test that has demonstrated usefulness in defining the anatomy of blood vessels of certain size in the head and neck. MRA serves as a complement to traditional MRI scanning in evaluation of the brain and neck.
Conventional angiograms, whereby contrast material is injected through a catheter into the blood vessels of the body are the gold standard (most accurate) for determining the anatomy of these vessels. The advantages of magnetic resonance angiogram is that it is faster and easier (it does not involve the catheters, contrast material, and risks of angiograms). Another advantage is that magnetic resonance angiogram also gives an image of the tissue of the brain.
Magnetic resonance angiogram is a general term that refers to various imaging techniques that are used to visualize the blood vessels by using magnetic resonance (MR) signal changes that are affected by changes in the flow of blood caused by changes in the shape of the blood vessels.
Magnetic resonance angiogram can be used to detect small ballooning of the blood vessels (aneurysms) as small as 4 millimeters in diameter. Smaller aneurysms can require an angiogram for detection. The sensitivity of magnetic resonance angiogram in detecting aneurysms can be affected by bleeding within the brain and the location of the aneurysms within the brain.
Magnetic resonance angiogram can also detect abnormal design (malformations), and atherosclerosis of blood vessels within the brain. Atherosclerosis of the carotid arteries of the neck can be visualized with magnetic resonance angiogram.
Magnetic resonance angiogram does not have significant application for the detection or definition of cancer of the brain.