How is mri of head done

Philadelphia, PA: Elsevier; chap 8. Editorial team. Head MRI. It does not use radiation. How the Test is Performed. Head MRI is done in the hospital or a radiology center.

You lie on a narrow table, which slides into a large tunnel-shaped scanner. How to Prepare for the Test. You may be asked not to eat or drink anything for 4 to 6 hours before the scan. Before the test, tell your provider if you have: Brain aneurysm clips An artificial heart valve Heart defibrillator or pacemaker Inner ear cochlear implants Kidney disease or are on dialysis you may not be able to receive contrast Recently placed artificial joint A blood vessel stent Worked with sheet metal in the past you may need tests to check for metal pieces in your eyes The MRI contains strong magnets.

This includes: Pens, pocketknives, and eyeglasses Items such as jewelry, watches, credit cards, and hearing aids Pins, hairpins, metal zippers, and similar metallic items Removable dental work. How the Test will Feel. Why the Test is Performed. An MRI provides detailed pictures of the brain and nerve tissues.

A brain MRI can be used to diagnose and monitor many diseases and disorders that affect the brain, including: Birth defect Bleeding subarachnoid bleed or bleeding in the brain tissue itself Aneurysms Infection, such as brain abscess Tumors cancerous and noncancerous Hormonal disorders such as acromegaly , galactorrhea , and Cushing syndrome Multiple sclerosis Stroke An MRI scan of the head can also determine the cause of: Muscle weakness or numbness and tingling Changes in thinking or behavior Hearing loss Headaches when certain other symptoms or signs are present Speaking difficulties Vision problems Dementia A special type of MRI called magnetic resonance angiography MRA may be done to look at blood vessels in the brain.

What Abnormal Results Mean. Abnormal results may be due to: Abnormal blood vessels in the brain arteriovenous malformations of the head Tumor of the nerve that connects the ear to the brain acoustic neuroma Bleeding in the brain Brain infection Brain tissue swelling Brain tumors Damage to the brain from an injury Fluid collecting around the brain hydrocephalus Infection of the skull bones osteomyelitis Loss of brain tissue Multiple sclerosis Stroke or transient ischemic attack TIA Structural problems in the brain.

Tests that may be done instead of an MRI of the head include: Head CT scan Positron emission tomography PET scan of the brain A CT scan may be preferred in the following cases, since it is faster and usually available right in the emergency room: Acute trauma of the head and face Bleeding in the brain within the first 24 to 48 hours Early symptoms of stroke Skull bone disorders and disorders involving the bones of the ear.

Alternative Names. Acoustic Neuroma Read more. Brain Aneurysm Read more. Brain Diseases Read more. Also, let your doctor know if you are unable to lie down for 30 to 60 minutes , or have had an allergic reaction to a contrast agent in the past that required medical treatment. Lastly, know tattoos may cause discomfort during the test due to traces of metal in ink. Knowing what to expect can help calm any of your anxiety about your MRI. Here are typical steps involved with getting an MRI.

First, medical technologists will instruct you to remove and store any metal materials in a lockable storage area. You may wear comfortable clothes that do not contain metal or change into medical scrubs top and pants or a hospital gown once you get to the MRI center. Medical staff will guide you into a special room that holds the MRI scanner. An MRI machine looks like a giant tube with openings at both ends. Newer machines are bigger and provide more space, which may help ease claustrophobia.

A short-bore system only scans the necessary part of the body, and allows the rest of the body to be outside of the magnet. For this type of scanner, only the upper part of your body would be inside the tube for a brain MRI. With an open MRI, all sides of the machine are open.

The technologist will give you a pillow or foam block to help keep your head in the right position. If you feel cold, a technologist can cover you with a sheet to make you more comfortable. You might experience a flushing sensation or a metallic taste in your mouth for a few moments after the injection. Contrast agents rarely cause allergic reactions. Besides the minor pinch of having a small needle IV, you should not feel pain with the contrast agent.

MRIs produce loud noises. The technologist will provide you with headphones that play music during your scan. These noises are normal and nothing to worry about. If you have trouble staying still or feel nervous about it, you may ask for a medication to help you relax. The technologist will be in another room to control the scanner, but will be able to see you the whole time through a window. Your technologist may ask you to hold your breath during the exam for a few seconds, depending on the test.

If at any time you feel anxious or want to stop the test, you can hit a call button on the machine and talk to staff through an intercom.

The technologist will guide you every step of the way to make sure you are as comfortable as possible. The solution is painless as it goes into the vein. The contrast highlights certain areas of the brain, such as blood vessels, so doctors can see more detail in specific areas. The technician will ask if your child is allergic to any medications or food before the contrast solution is given.

The contrast solution used in MRI tests is generally safe. However, allergic reactions can occur. Talk to your doctor about the benefits and risks of receiving contrast solution in your child's case. As the exam proceeds, your child will hear repetitive sounds from the machine, which are normal.

Your child may be given headphones to listen to music or earplugs to block the noise, and will have access to a call button in case he or she becomes uneasy during the test. If sedated, your child will be monitored at all times and will be connected to a machine that checks the heartbeat, breathing, and oxygen level. Once the exam is over, the technician will help your child off the table; if sedation was used, your child may be moved to a recovery area.

An MRI exam is painless. Your child may have to lie still on the MRI table for minutes during the procedure, but there are brief breaks between each scan. If your child feels cold lying on the MRI table, a blanket can be provided.

Unless sedation was used or you are told otherwise, your child can immediately return to normal routines and diet. Most sedation wears off within hours, and any contrast material given should pass through the body in about 24 hours. The MRI images will be viewed by a radiologist who's specially trained in interpreting the scans.

The radiologist will send a report to your doctor, who'll discuss the results with you and explain what they mean. In most cases, results can't be given directly to the patient or family at the time of the test. If the MRI was done on an emergency basis, the results can be made available quickly. MRIs are safe and relatively easy. No health risks are associated with the magnetic field or radio waves, since the low-energy radio waves use no radiation. The procedure can be repeated without side effects.

If your child requires sedation, you may discuss the risks and benefits of sedation with your provider.