What Is the Difference between an MRI and MRA?

Magnetic resonance imaging (MRI) provides general imaging of the inside of the body, while magnetic resonance angiography (MRA) offers a specific picture of the blood vessels. MRA scans use MRI technology, but provide a narrower focus than would be available with a regular MRI study. The key difference between MRI and MRA is their intended uses and applications, as the MRA is used for a very specific purpose, while MRIs can be employed in many different settings.

Both MRI and MRA studies offer high resolution images with few risks for the patient. In an MRI study, a patient enters a tube with powerful magnets used to collect a noninvasive series of images from inside the body. This is done with a high degree of resolution, and without exposure to radiation. MRIs can be taken of any area of the body, and some may involve the use of contrast materials to highlight certain structures inside the patient. Whole body MRI scans offer imaging from head to toe, while other scans can center on areas of interest like a knee injury or a suspected abdominal cancer.

For a look at the blood vessels with an MRA study, a care provider injects a contrast material that will highlight the blood vessels. The equipment can be positioned over a particular area, like the leg, or can run across the whole body. Doctors may request an MRA for something like a suspected blood clot, to evaluate the flow of blood in a given area of the body and check for obstructions. It offers detailed imaging in a noninvasive way, in contrast with other angiography techniques.

A patient may need an MRI and MRA scan to collect information about a health condition, depending on the nature of the issue and the doctor's recommendations. These scans may be used during the diagnostic phase to collect information about what is happening inside the patient. They can also be useful in follow-up to monitor the progress of healing. Doctors can compare newer and older studies to determine how well a patient responded to treatment and to check for complications.

The experience of MRI and MRA studies is very similar. In both cases, the patient needs to lie down and hold as still as possible inside the machine. Open machines allow for more comfort in cases where patients feel claustrophobic, while older closed models can be stressful for some patients. Care providers may offer headphones with music and other distractions for their patients during MRI and MRA scans, along with an emergency stop button to use in the event of extreme discomfort.