Magnetic resonance imaging (MRI) is an imaging modality that utilizes magnetic fields and electromagnetic energy to produce detailed pictures of the body's tissues and organs without using x-rays. The procedure is painless, and the magnetic field is not known to cause tissue damage of any kind.
MR angiography (MRA) is an MRI study that uses specialized imaging techniques to visualize only the blood vessels. MRA is routinely used to evaluate the circulation within the brain and the vessels of the neck that supply the blood to the brain. This is often performed in conjunction with an MRI of the brain to provide for a more comprehensive evaluation of patients that have symptoms related to diminished blood flow to the brain.
MRA is utilized in the evaluation of the aorta, both within the chest and abdomen. MRA of the abdominal aorta also provides information about the blood supply to the kidneys and the abdominal organs. The blood vessels of the upper and lower extremities can also be evaluated by MRA. The aorta and extremity MRA studies are typically performed using a small amount of intravenous contrast (gadolinium).
Since MRA does not use iodinated x-ray contrast material, the study can be performed on patients with kidney problems and those with a history of x-ray contrast reactions.