What is Magnetic Resonance Imaging (MRI) of the Brain?
Magnetic resonance imaging (MRI) of the brain is a non-invasive, painless diagnostic imaging procedure that creates detailed images of your brain using radio waves and a strong magnetic field. It is also known as a cranial MRI or head MRI.
How does the MRI Work?
MRI scanning involves the use of radio waves that temporarily realigns hydrogen atoms in the body without causing any chemical changes. As the hydrogen atoms return to their normal position, they emit varying amounts of energy depending on the type of tissue they are in. The MRI scanner captures the energy variation and creates detailed images based on this information.
Uses of MRI of the Brain
Magnetic resonance imaging of the brain may be ordered by your doctor to help diagnose conditions such as:
- Hydrocephalus (excess collection of cerebrospinal fluid in the brain)
- Brain aneurysms (localized swelling in the blood vessels in the brain)
- Clots or blockages in the brain
- Hemorrhage or internal bleeding within the brain
- Epilepsy
- Stroke
- Brain tumors
- Pituitary gland disorders
- Eye and ear disorders
- Conditions such as multiple sclerosis, which cause changes in the brain
- Brain infections
Indications for MRI of the Brain
MRI of the brain may be indicated if you have had a stroke or sustained a head injury and have symptoms such as:
- Dizziness
- Weakness
- Blurring of vision
- Loss of consciousness
- Chronic headaches
- Changes in behavior
Preparation for MRI of the Brain
- Inform your doctor regarding any health conditions, previous surgeries, implants or metal placed within your body, the likelihood of pregnancy, and allergies.
- Leave all jewelry at home. Wear loose-fitting comfortable clothing that does not contain any metal fasteners, or you may be asked to wear a hospital gown.
- Follow the eating and drinking restrictions given by your doctor.
- You can continue to take your regular medications unless otherwise specified.
Procedure for Magnetic Resonance Imaging of the Brain
The procedure for magnetic resonance imaging of the brain involves the following basic steps
- You will be placed comfortably on a movable scanning table.
- Bolsters or straps may be used to help you remain still.
- A device containing coils that send and receive radio waves is placed around your head.
- You may be offered earplugs to avoid being distracted by the noises made by the MRI machine or you can choose to listen to music through headphones during the procedure.
- An IV line will be placed into your arm to inject contrast material if required.
- The scanning table will be moved into the magnet of the MRI machine.
- The technologist will perform the examination from another room taking multiple pictures of the brain, each lasting several minutes.
- You will be required to remain as still as possible to obtain the clearest images.
- A microphone in the MRI machine allows you to talk to the technologist.
- The entire procedure will be completed within 45 minutes to an hour.
What happens after Magnetic Resonance Imaging of the Brain?
You can return to your routine activities and resume your normal diet immediately after the procedure. If sedation was provided to help you relax, you may have to wait until the effects of sedation wear off before returning to your routine activities. A radiologist or trained doctor will analyze the images and send the report to your doctor, who will share the results with you.
Risks of Magnetic Resonance Imaging of the Brain
- The strong magnetic field produced by the MRI does not cause any harmful effects, except for malfunctioning of implanted devices which can distort the images.
- There may be an allergic reaction to contrast dye. These reactions are usually mild and can be easily controlled with medication.
Benefits of Magnetic Resonance Imaging of the Brain
- Produces highly detailed images of the brain and other cranial structures
- Detects abnormalities that may be obscured by bone with other imaging studies
- Virtually no side effects as there is no exposure to harmful radiation
What is a Head CT Scan?
Computerized tomography (CT) scan is an imaging technique that uses a combination of a special X-ray machine and a computer to obtain cross-sectional images of the internal structures of the body. A contrast material or dye may be injected into a specific part of your body to obtain a more detailed view. The images obtained are used to diagnose a variety of diseases. A CT scan is also called Computerized Axial Tomography (CAT) scan.
Head CT scan is used to obtain pictures of the skull, brain, blood vessels (head), sinuses, etc.
Indications for a Head CT Scan
A head CT scan is indicated to:
- Diagnose skull bone abnormalities, birth defects, abnormal blood vessels, location and size of tumors, brain hemorrhage, stroke, infections, etc.
- Evaluate sinuses, pineal gland or pituitary gland.
- Diagnose the cause of an abnormal mental state, headache, muscle weakness, seizures, loss of vision or hearing, speech difficulty, etc.
Preparation before a Head CT Scan
A radiology technician will ask questions about your medical history. Talk to your doctor about the medicines you are taking and those you should stop taking prior to the procedure. Do not eat or drink at least 3 hours before the procedure. Inform your doctor if you are pregnant, diabetic, have kidney disorders, or are allergic to certain medications.
Head CT Scan Procedure
The procedure is done on an outpatient basis and involves the following steps:
- You will wear a hospital gown and lie on a table that is attached to the CT scanner.
- You may need to swallow the contrast preparation or have an IV line started in your arm if the CT scan involves contrast dye. Inform your technician if you feel any allergy symptoms such as sneezing, itching, etc.
- Your head will be stabilized with a pillow or a strap so you can lie still for the procedure.
- Speakers inside the scanner enable you to communicate with the technician.
- The table will slide into a large donut-shaped machine which takes images while moving around your head, yielding several images (slices) from different angles. It is normal to hear loud, clicking sounds. A computer will transform slices into 3-dimensional images for your doctor to view.
- You may be asked to hold your breath for a few seconds during image capturing.
- The IV line is disconnected and you are removed from the scanner once the procedure is completed.
After the Procedure
You need to drink 6-8 glasses of water to flush out the contrast dye. You can resume usual activities and diet. Your doctor will discuss the results within 48 hours of the procedure or during your follow-up visit. Diabetic patients are required to follow special instructions about their medications for the first few days after the procedure.
Complications of a Head CT Scan
Complications are rare. Some patients may experience slight discomfort or allergic reactions to the contrast dye. Radiation exposure damage may occur in rare cases.
