An MRA, or magnetic resonance angiogram, is a type of imaging study that produces pictures of a patient's blood vessels through the use of radio waves and a magnetic field, explains WebMD. A physician uses magnetic resonance angiography to help diagnose restricted blood flow or abnormalities in blood vessels.
Doctors commonly order a magnetic resonance angiogram to examine blood vessels that supply blood to the legs, heart, lungs, brain and kidneys, notes WebMD. An MRA can provide information that other types of imaging studies, including X-rays and ultrasounds, cannot. For instance, an MRA can help detect brain conditions, including clots, aneurysms and deposits of calcium or fat that restrict blood flow to the brain. An MRA of the aorta is useful in identifying tears and aneurysms that interfere with the heart's ability to pump blood throughout the body. An MRA helps identify stenosis, which is a narrowing of the blood vessels, in various areas of the body.
Prior to having an MRA scan, a patient receives contrast material, which makes it easier for the doctor to view the blood vessels in the images, WebMD explains. The patients lies inside of an MRI or magnetic resonance imaging machine, which looks like a long, narrow tunnel, notes Children's Hospital of Pittsburgh. Patients who suffer from claustrophobia often have an option to take a sedative to calm the nerves. As an alternative, a patient can undergo the scan inside of an open MRI machine, which has a less confined space than a closed MRI machine, notes WebMD.