Brain MRI
Uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and other cranial structures that are clearer and more detailed than other imaging methods.
This exam does not use ionizing radiation and may require an injection of a contrast material called gadolinium, which is less likely to cause an allergic reaction than iodinated contrast material.
MR imaging of the head is performed for a number of abrupt onset or long-standing symptoms. It can help diagnose conditions such as:
- brain tumors
- stroke
- infections
- developmental anomalies
- hydrocephalus — dilatation of fluid spaces within the brain (ventricles)
- causes of epilepsy (seizure)
- hemorrhage in selected trauma patients
- certain chronic conditions, such as multiple sclerosis
- disorders of the eye and inner ear
- disorders of pituitary gland
- vascular problems, such as an aneurysm (a bubble-like expansion of the vessel), arterial occlusion (blockage) or venous thrombosis (a blood clot within a vein)
During the exam, it’s important to stay still to obtain the clearest images. Children who have difficulty staying still may need intravenous or oral sedation. Sedation can also be helpful for adults who are claustrophobic.
You will lie down on a table that slides into the MRI machine. The table slides through a large magnet shaped like a tube. You may have a plastic coil placed around your head. After the table slides into the machine, a technician will take several pictures of your brain, each of which will take a few minutes. There will be a microphone in the machine that allows you to communicate with the testing staff.
The test normally takes 30 to 60 minutes. You may receive a contrast solution, usually gadolinium, intravenously to allow the MRI machine to see certain parts of the brain more easily, particularly your blood vessels. The MRI scanner will make loud banging noises during the procedure. You may wear earplugs or headphones to block the MRI machine’s noises, or you may listen to music during the test.
There are no risks associated with the MRI itself. There is a very slight chance that you will have an allergic reaction to a contrast solution. Tell the medical staff if you have decreased kidney function; it may not be safe to use contrast solution if this is the case.
After the test, you can get dressed and leave the testing facility. If you were sedated for the exam, staff may move you to a recovery area until you wake up — usually one to two hours after you received the sedative.
A radiologist will analyze your MRI images. They will provide your doctor with the results. Your results will be available quickly if your head MRI was an emergency procedure. Next steps will depend on whether the results revealed anything unusual or discovered the cause of any abnormalities.