Brain MRI Scan: What You Should Know

What is a brain MRI scan?

Brain magnetic resonance imaging, or a brain MRI scan for short, is a non-invasive imaging technique that uses a large magnet, radio waves, and a computer to create detailed images of the brain. It creates images by sending bursts of radio waves into the head, which are then measured by the computer as the signals bounce back.

This imaging test is commonly used to examine brain structures, identify abnormalities, and assist in diagnosing various neurological conditions. To help provide higher clarity and detail, a brain MRI can be performed with or without contrast agents, depending on your clinical need.

Why is a brain MRI done?

A brain MRI is performed to investigate sudden-onset or long-lasting symptoms, such as chronic headaches, dizziness, seizures, or behavioural changes. It helps detect structural abnormalities, injuries, or diseases affecting the brain. Additionally, it can monitor the progression of neurological conditions like multiple sclerosis or assess the effects of trauma.

Another form of brain MRI that can be performed is a functional MRI (fMRI) of the brain, mostly done on people who might have to undergo brain surgery. An fMRI can pinpoint areas of the brain responsible for speech, language, and body movement by measuring metabolic changes that take place in your brain when you perform certain tasks. 

During this test, you may need to carry out small tasks, such as answering basic questions or tapping your thumb with your fingertips. Additionally, there is a type of MRI called magnetic resonance angiography (MRA), which better examines the blood vessels in the brain.

MRI with or without contrast agent

What can a brain MRI detect?

Brain MRIs show the structures inside of your head, including your brain, neural blood vessels, cranial nerves, optic nerves, facial bones, skull, surrounding soft tissues, and more. Thus, it can help diagnose different brain conditions, such as:

1. Stroke and stroke damage

2. Changes associated with ageing (brain volume loss or signal changes in brain tissue)

3. Brain damage or bleeding from traumatic injury

4. Loss of body movement control (ataxia)

5. Brain tumours

6. Developmental anomalies

7. Hydrocephalus, dilatation of fluid spaces within the brain (ventricles)

8. Causes of epilepsy (seizure)

9. Certain chronic conditions, such as multiple sclerosis

10. Eye and inner ear disorders

11. Pituitary gland disorders

When will I need to do a brain MRI?

Your doctor may recommend a brain MRI to determine if you have sustained any damage from a stroke or head injury. They may also recommend a brain MRI if you’re experiencing symptoms that indicate a condition of the brain, such as:

1. Persistent headaches

2. Vision problems

3. Memory loss or confusion

4. Weakness or numbness in limbs

5. Symptoms of stroke or neurological disorders.

Additionally, the brain MRI can provide clearer images of parts of the brain that can't be seen clearly on an X-ray, computed tomography (CT) scan, or ultrasound, making it particularly valuable for finding problems with the pituitary gland and brain stem.

If you’re experiencing any of the above symptoms, don’t hesitate to request an appointment with Thomson Medical. Our specialist will help guide you through the MRI process, answer any questions you may have, and provide you with tailored recommendations.

How do I prepare for the brain MRI scan?

Preparing for a brain MRI is fairly straightforward; you will need to arrive early to check in and complete an MRI safety form beforehand. The medical staff assisting you will also ask you if you have any metal in your body, such as:

• Inner ear implants

• Artificial joints

• A defibrillator or pacemaker

• Particular types of heart valves

• Vascular stents

• Brain aneurysm clips

Afterwards, the medical staff will also ask if you have previously worked with sheet metal or been injured by metal shrapnel, as these factors will affect how safely you undergo an MRI. You are also prohibited from bringing electronic devices into the MRI room.

If you have body piercings or are wearing anything that contains metal, including jewellery or sunglasses, you will need to remove those items. Metal interferes with the MRI machine's ability to produce a clear image. Braces and dental fillings usually won't pose a problem, but pens, pins, and certain dental appliances can cause interference.

Be sure to also wear comfortable clothing, as the staff may ask you to wear a hospital gown or clothing that doesn't contain metal zippers or metal fasteners.  Do not wear clothing made out of spandex material or anti-bacterial materials, as they may contain metallic threads that cause skin burns when they interact with the magnetic field.

Also inform the medical staff if you're pregnant, as the magnetic field of the MRI may affect unborn children in a way that isn't yet fully understood. Additionally, it's important to let the staff know if you have claustrophobia. They may recommend that you take sedatives during the examination or undergo an “open” MRI, which are MRI machines that have wider tunnels.

What happens during the procedure?

During the scan:

1. You will lie on a movable exam table that slides into the MRI machine.

2. If you have claustrophobia, or a child getting an MRI scan has trouble staying still, a sedative may be administered to them prior to the scan.

3. Earplugs may be provided to reduce noise from the MRI machine, as the MRI scanner will make loud banging noises during the procedure.

4. A helmet-like device (brain coil) may be placed around your head.

5. If contrast is required, an IV line will be inserted into your arm.

6. After the table slides into the machine, an MRI technician will take several pictures of your brain; each will take a few minutes.

7. It is normal for the area being imaged to feel slightly warm. There will be a microphone present in the machine, allowing you to communicate with the staff if it bothers you.

8. The scan lasts 30 to 60 minutes while you remain still to ensure clear images.

What happens after the procedure?

After the scan, the technologist may ask you to wait while the radiologist reviews the images to determine whether more are necessary. The technologist will then remove your IV line (if you needed sedation or contrast dye for the procedure) and place a small dressing over the insertion site. 

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. If contrast dye was used for the scan, remember to drink extra water to help flush it out.

If you did not require sedation, no recovery period is necessary. You may resume your usual activities and normal diet immediately after the exam. On very rare occasions, a few patients experience side effects from the contrast material. These may include nausea, headache, and pain at the site of injection. 

It is very rare that patients experience hives, itchy eyes, or other allergic reactions to the contrast material. If you have allergic symptoms, tell the technologist. A radiologist or other doctor will be available for immediate assistance.

Are there any risks associated with the procedure?

While generally safe, some risks include:

• Allergic reactions or metallic taste in mouth due to contrast agents

• Claustrophobia during the scan

• Discomfort from lying still for extended periods

• Magnetic field interference with implants (e.g., pacemakers).

How do I interpret my results?

A radiologist, a doctor trained to interpret the MRI brain scan results, can identify if you have any abnormalities such as tumours, inflammation, or vascular issues. The radiologist will then send a signed report to your necessary healthcare provider, who will share the results with you.

You may also need a follow-up exam to further evaluate a potential issue with more scans or with a special imaging technique. It may also show if there has been any change in the issue over time. Follow-up exams are often the best way to see if treatment is working or if a problem needs attention.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice, please consult a specialist at Thomson Medical. Request an appointment with Thomson Medical today.

FAQ

What is the difference between a brain MRI and a head MRI?

A brain MRI focuses specifically on brain structures, while a head MRI includes surrounding tissues like the skull and sinuses.

What does an MRI of the brain show?

It shows detailed pictures of brain anatomy, including abnormalities like tumours, strokes, or degenerative diseases.

How long does an MRI of the brain take?

Typically, 30 to 60 minutes, depending on whether contrast is used.

Is an MRI better than a CT scan for the brain?

MRI provides more detailed images of soft tissues than CT scans but takes longer. CT scans are preferred in emergencies like trauma due to their speed. For more information on this, read up on our article comparing CT scans and MRIs here.

What are the most common findings on a brain MRI?

Common findings include tumours, strokes, multiple sclerosis lesions, and vascular abnormalities.

What are the benefits and risks of a brain MRI?

Benefits include detailed imaging without radiation exposure and early stroke detection; risks involve allergic reactions to contrast agents or discomfort from claustrophobia.

Does your whole body go into the machine for a brain MRI?

No, only your head enters the machine while scanning your brain

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice, please consult a specialist at Thomson Medical. Request an appointment with Thomson Medical today.