An MRI (Magnetic Resonance Imaging) of the head is a form of diagnostic medical imaging that produces very clear pictures of the brain, skull, and surrounding tissues using radio waves and a large magnetic field. It can produce very high definition images of the brain which allow doctors to identify disorders like tumors, hemorrhage, strokes, inflammation, infections, and other abnormalities.
For an MRI of the head, the patient lies on a slide table that goes into the tunnel-shaped machine that uses the board and a magnetic field to identify images related to the head. The sterile equipment forms a strong magnetic field around the head region in order to use the body’s water molecules proton alignment. After creating the magnetic filed the MRI machine sends radio waves into the body, and the water protons will emit a signal that the MRI can sense and generate images. The MRI is a non-invasive procedure, which means the procedure does not require surgery and does not use ionizing radiation, making the MRI a very safe and effective diagnostic tool.
Why is a head MRI necessary?
Your physician may suggest you have a head MRI due to a variety of conditions. Some of the most common include:
Headaches: If your headaches are severe or frequent, it is possible a head MRI will be ordered to find the exact cause.
Seizures: An MRI of the brain may be used to locate the source of seizures.
Vertigo or dizziness: If you have repeated episodes of vertigo or dizziness, your doctor may request an MRI to help determine the cause.
Stroke: An MRI can be used to diagnose a stroke and determine its location and extent.
Tumours: If there is a suspicion of a brain tumour, an MRI can be ordered of the brain to look for tumours.
Trauma: An MRI can be used to assess brain injury after a traumatic injury such as a concussion.
Multiple Sclerosis: The disease, multiple sclerosis which is an attack on the central nervous system, can be diagnosed and followed using an MRI.
Types of Head MRI Scan
There are several types of head MRI scans, all of which serve different purposes. The most common types of scans include:
T1-weighted MRI: This type of MRI scans is great for producing good images of the white and grey matter of the brain.
T2-weighted MRI: This type of MRI scans is effective at visualizing changes to brain tissue associated with disease or injury such as swelling, infection or inflammation.
FLAIR MRI: These MRI images are valuable for evaluating fluids in the brain due to potential abnormality that is causing the pathology seen with brain tumours and multiple sclerosis.
Diffusion-weighted MRIs: Used for their sensitivities to identifying changes in brain tissue due to strokes and other disease processes, diffusion-MRIs identify changes in brain tissue due to limitation of the movement of the water molecules.
Perfusion MRI: This type of MRI scans measures perfusion or blood flow to the brain and can highlight areas of brain tissue where blood flow has been affected due to disease such as stroke or other disease characteristics.
Magnetic resonance angiography (MRA): This is an MRI scan of the brain with a focus on an evaluation of the blood vessels in the brain and will exhibit vascular pathology such as aneurysms and arteriovenous malformations.
How do I prepare for a head MRI?
Here are a few general tips to consider when making preparations for a head MRI:
Be sure to mention all of your medical conditions, including kidney disease, to your doctor for the needed preparation process an MRI may require.
Be aware of any specific preparation advice your doctor may give you. This could mean stopping specific medications for a specific time period before the study, or perhaps dressing comfortably in non-metal zippers or buttons.
Metal can interfere with the magnetic field and produce images that are not as clear, so prior to your scan, remove all metal jewelry and accessories.
If you have any implants or devices with metal in your body including pacemakers, cochlear implants, metal plates, or screws in your head, let the MRI technician know. Some of those items may not be safe with an MRI.
If you are claustrophobic or are anxious about being in confined spaces, talk to your doctor about if any medication or relaxation techniques might help you.
What is the process of a head MRI?
The typical head MRI procedure is:
Prior to the MRI test, you will change into a hospital gown and remove all jewelry, watch, and hairpins prior to your test. The technician may have you complete an MRI Head Screening form for your safety during the MRI.
You will be lying down on a sliding table that will enter the MRI machine. Your head will be placed in a head rest, and the technician may put a coil around your head to improve the clarity of the image.
To help reduce the noise of the machine, the technician can provide you ear plugs or headphones for the test. The technician will communicate with you during the scan via a two-way intercom, and during the scan to reduce image blurring, you will be asked to hold as still as possible.
The MRI scanner will take pictures of your brain while it makes a variety of annoying thumping and buzzing sounds. Depending on the scan and the amount of information needed, the scan could take 30 – 60 minutes to complete.
Once the scan has completed, the technician will help you off the table and provide you some last instructions. After the scan, you may continue with your regular activities right away.
Conclusion
An MRI scan of the head is a safe, non-invasive test that can produce detailed images of the brain and head tissues. It is important to prepare properly for the MRI scan. Removing all metal items and being truthful with your doctor about pre-existing health conditions are all ways to ensure the MRI scan runs smoothly and the results are accurate.
Remaining still and paying attention to the appropriate responses during the MRI scan are essential for obtaining clear images of the head.
After the MRI the patient usually can return to their usual activities, and the doctor will discuss the results with the patient and also discuss next steps. If at any time during the MRI process you have a question or concern, do not hesitate to ask your healthcare provider.
Frequently Asked Questions
Q. What do I need to do to prepare for a head MRI?
You need to remove all metal objects (jewelry, hairpins, eyeglasses, etc.), wear clothing made of non-metal material, and notify the staff about any implants, pacemakers, or conditions such as claustrophobia or kidney problems.
Q. Should I eat, or take my medication, before my scan?
You will usually be able to eat and take your medications as prescribed unless your doctor has specified otherwise (e.g. if you will receive contrast dye).
Q. What will happen during the head MRI?
You will be lying on a table which slides into the MRI machine. Because of the loud noise a head MRI causes, you will be given earplugs or headphones to wear. As images are taken, you will need to lie still for approximately 30 – 60 minutes, but you will be able to communicate with the staff if necessary.
Q. What will happen immediately after my MRI?
You will be able to put your own clothes back on, collect your belongings and leave, or do whatever you like, unless you have been sedated. In that case, you should rest and arrange for someone to drive you home.
Q. Are there any risks or special instructions after my scan?
Usually, there are no special instructions after a head MRI. If you received contrast dye, you should watch for rare allergic reactions, and continue medications as directed.
