A magnetic resonance angiogram is a medical imaging study of the blood vessels performed with a magnetic resonance imaging (MRI) machine. This may also be known as an MRI angiogram. In contrast with traditional angiography, it is noninvasive, and the risks to the patient are significantly lower. A doctor may recommend this option if it is available because not only is better for the patient, it can also provide very high resolution images that may highlight structures that do not show up on other tests.
In a magnetic resonance angiogram, the patient lies inside an MRI machine. It generates a magnetic field with no ionizing radiation, unlike conventional and CT angiography procedures. A tracer material highlights the blood vessels in the area of interest so they will show up clear and crisp on the resulting images. The test can take half an hour to an hour, depending on the area of the body being imaged.
Contrast materials used in MRI studies are less likely to cause allergic reactions than those used in x-ray procedures. This can be beneficial for patients with known allergy issues, especially those who have had reactions to contrast before. Patients with known iodine allergies may not be good candidates for a magnetic resonance angiogram, but otherwise they should be able to have the test without any ill effects. For patients who experience distress in confined spaces like MRI tubes, a doctor may prescribe a sedative or recommend use of an open MRI machine.
Another advantage to a magnetic resonance angiogram is that it does not require catheterization. This reduces risks for the patient and will also make the test much more comfortable. The test can be used to look at blood vessels in the head, abdomen, legs, and chest and may provide important information a doctor can use in diagnosis and treatment. It may be necessary to return for an angioplasty procedure to repair blood vessels.
Before a patient can receive a magnetic resonance angiogram, the technician will go over some questions to make sure the test will be safe. Any metal devices inside the patient's body could be a cause for concern. Patients will also need to remove all metal from their bodies, including earrings, wedding jewelry, and other accessories. For some tests, the patient may need to fast first to allow the technician to get a better image. This is usually recommended in the case of abdominal angiograms; for something like a head magnetic resonance angiogram, it is typically fine to eat first.