Magnetic Resonance Imaging, or MRI, can be used to look at brain structure, blood flow, metabolic activity and problems in the brain. MRI can help diagnose brain tumors, infections, hormonal disorders, abnormal brain structure and stroke. It may also be used to determine the cause of headaches, investigate developmental abnormalities and study changes in behavior. The results are analyzed and interpreted by a radiologist.
Equipment
The MRI machine is actually a large tube with a circular magnet. It uses pulsed radio waves and a magnet 10,000 times stronger than that produced by the earth, according to Medline Plus. Some are entirely closed, while others, called open MRI machines, have open sides. The computer to analyze the returning radio waves is in a separate room. The radiographer works from this room and can see the patient through a glass window during the procedure.
Science
When a person is placed into the MRI machine and the magnet is turned on, it causes all the hydrogen atoms of the brain to line up in one direction. Radio waves are sent into the person's head and these waves bounce back and are recorded with a computer. These images, called slices, can be printed or stored on computer for analysis.
Scan
For a scan, the individual being scanned dresses in a hospital gown and removes all metal they might be wearing, such as jewelry. The person then lies on a long table and has coils placed on his head to boost the activity of the radio waves. The person, on the table, is then slid into the MRI machine and the radiologist turns on the machine and starts recording images. It takes two to 15 minutes to record a single brain image and a single MRI session may last an hour or more. For some brain MRIs, a contrast dye may be administered via IV during the procedure. If the brain MRI is intended to look at a particular aspect of metabolic activity, the patient may need to perform some action or task while in the machine to cause a specific portion of the brain to activate.
Reaction
According to RadiologyInfo.org, some people experience feelings of claustrophobia when inside the MRI machine. Others may become uncomfortable remaining still within the machine for long periods of time. The machine can be noisy, so some patients choose to wear earplugs during the procedure. During the brain scan, the head may become warm.
Considerations
Overall, MRI is considered to be a safe procedure, according to Medline Plus. Because MRI uses a giant magnet, metal objects should not be brought into the room with the equipment, and people with metal implants in their bodies should discuss this with a physician before having an MRI.
