How often should you get an MRI?

How Often Should You Get an MRI? A Comprehensive Guide

MRI or magnetic resonance imaging is an advanced medical imaging technique that captures detailed 3D images of the inside of the human body. Unlike a CT scan or X-ray, it does not use ionising radiation, which is why it is generally considered safe to have multiple MRI scans.

However, if you are wondering “how often should I get an MRI?”, it will partly depend on the recommendations of your doctor and what concerns have led you to considering an MRI scan.

Other factors influencing the frequency of MRI scans include whether:

you have any symptoms of ill health that are progressing
you have developed any new symptoms since your last MRI scan
any underlying health condition was identified during your last MRI scan
you have started treatment for a health condition that needs to be monitored with MRI.

Here, we will explore how an MRI scan works, what to expect during a scan, and the risks and benefits of MRI. We will also reveal when an MRI scan is not appropriate and what conditions an MRI scan can help identify.

How MRI works

Magnetic Resonance Imaging uses powerful magnets and radio waves to produce detailed images of the inside of your body. This is possible because of the way water molecules in your body react to the magnetic field created by the MRI machine and the radio waves it releases.

Water molecules are made of two hydrogen atoms and one oxygen atom. The hydrogen atoms contain even smaller particles called protons. When an MRI machine creates a magnetic field around your body, it causes the protons to all point in the same direction.

When the MRI machine then releases bursts of radio waves, these protons are knocked out of alignment. When the radio waves stop, the protons return to their previous positions where they were all lined up due to the power of the magnetic field.

How quickly the protons realign and how much energy they release doing this varies from one tissue to the next and within tissues. The energy released is detected by the MRI machine. These signals are then converted into visual information. This results in images of the inside of your body.

MRI scan images

MRI scan images are black, white and varying shades of grey.

Black means there was no MRI signal. This occurs either because no energy was released from this area of the body or the amount released was so low that it could not be detected by the MRI machine. Parts of the body with no or little water do not release much energy. Air and hard bone, therefore, appear black on an MRI scan.

White means there was a high MRI signal ie a high amount of energy was released. This occurs in areas where there is a lot of water, such as areas of inflammation, fat and fluid build-up.

Most soft tissues appear as varying shades of grey. However, areas of disease due to cancerous growths, swelling or infection appear brighter.

The MRI machine

An MRI machine is a large tube-shaped structure. The tube comprises three layers that each have a different function. These layers include:

radiofrequency coils – this is the innermost layer of the MRI tube and produces radio waves
metal gradient coils – this layer sits behind the radiofrequency coils and enables all of the visual information captured to be assigned to a specific location within the body
a magnet – this is the outermost layer of the MRI tube and creates a strong magnetic field.

The middle of the tube-shaped structure of the MRI machine is called a bore. During your scan, you will lie back on the MRI scanner table, which slides into the bore. This allows the MRI machine to create a magnetic field that completely surrounds your body.

What are the risks of MRI?

MRI is considered one of the safest medical procedures. This is because no ionising radiation is used, unlike other medical imaging procedures like CT scans. However, as the scan takes place within the tube-shaped structure of the MRI machine, if you have claustrophobia, you may find lying down in the MRI machine challenging.

The MRI machine makes loud banging, whirring and tapping noises. This is due to the metal gradient coils within the MRI machine. When you are lying down in the hollow part of the machine, these sounds can echo and become louder. Some people find these sounds unnerving.

It is, therefore, important to tell your care team if you are feeling anxious about your scan, so they can help you feel as comfortable as possible. The MRI machine allows for two-way communication, so you can ask for the scan to be paused or stopped at any time. Your care team can also provide you with earplugs if needed.

If you have claustrophobia, it can be helpful to practice techniques to ease your anxiety eg mindfulness, visualisations and breathing techniques. You can also bring a friend or family member with you to help put you at ease.

Risks of MRI contrast agent

For certain MRI scans, you may be asked to have a contrast agent (sometimes called a contrast dye) to improve the clarity of the images captured. For MRI scans, a contrast agent called gadolinium is used. This is a rare earth metal that affects the magnetic properties of the hydrogen atoms that make up the water molecules in your body.

Most people tolerate gadolinium well. However, around one in 1,000 people who are given gadolinium develop an allergic reaction. This reaction usually occurs within an hour of receiving gadolinium.

As individuals who have a contrast agent are asked to remain at the scanning facility for at least 30 minutes after their scan is complete, allergic reactions tend to occur at the scanning facility where medical help is readily available.

There is evidence that individuals who have multiple MRI scans with gadolinium have gadolinium deposits in their brains. However, there is currently no evidence that suggests these deposits cause any harm.

What are the benefits of MRI?

MRI captures the most detailed images possible of tissues and organs within your body. This allows MRI scans to detect subtle changes within and between body tissues. Consequently, diseases and damage from injuries can be detected at earlier stages – in some cases, even before you notice any symptoms.

For conditions such as cancer, early detection via an MRI scan can have a significant impact on the success of treatment. For other diseases and injuries, early detection can mean you receive treatment sooner and avoid unnecessary pain or discomfort.

Also, as ionising radiation is not used, MRI scans are safe procedures for pregnant women in their second and third trimesters.

Restrictions on who can have an MRI scan

MRI scans are not suitable for everyone. If you have metal fragments or implants within your body that are not MRI-compatible, an MRI scan may not be safe for you.

This is because the powerful magnets used in an MRI machine can cause the metal to shift in your body. Also, the radio waves released by the MRI machine can cause the metal to heat up and damage surrounding tissue.

Today, metal implants are often designed to be MRI-compatible. For example, modern pacemakers and neurostimulators can be switched into safe mode during an MRI scan.

Metal clips and coronary artery stents implanted during surgery are also often made of non-ferrous or weakly ferrous materials. This means they do not have any magnetic properties or have very weak magnetic properties. They, therefore, will not be affected by the MRI machine.

However, some metal implants are not compatible with MRI scans, such as certain aneurysm clips and older pacemakers. Shrapnel may also be incompatible with MRI depending on the type of metal it is made from.

It is, therefore, important to tell your care team about any metal implants or fragments in your body, including cochlear implants, stents, pacemakers, clips, shunts and shrapnel. They can then confirm whether or not it is safe for you to go ahead with your MRI scan.

Conditions an MRI scan can help diagnose

MRI scans can help detect abnormalities, diseases and injuries affecting any organ in your body, as well as your soft tissues and bony structures. This includes but is not limited to your:

bowel – MRI can identify inflammation and swelling of the bowel, as well as abscesses and small tears
brain – MRI can help diagnose aneurysms, strokes, traumatic brain injuries and tumours
breast – breast MRI is often recommended for women at high risk of developing breast cancer to enable early detection
spinal cord – MRI can help detect Alzheimer’s disease, nerve compression, multiple sclerosis, spinal stenosis and congenital (from birth) structural problems
heart – cardiac MRI can detect congenital heart problems, cardiomyopathy, heart valve disease and coronary artery disease
joints – MRI can detect torn cartilage and ligaments, bone infections and bone tumours
prostate – a prostate MRI can help diagnose prostate cancer, an enlarged prostate gland (benign prostatic hyperplasia) and prostatitis
womb – a gynaecological MRI scan can detect endometriosis, uterine fibroids and womb cancer.

Once a disease or tissue damage has been diagnosed, MRI can also be used to plan and track the progress of any treatment that follows. It is, therefore, used more often if you are undergoing cancer treatment. It is also used to identify whether cancer has spread to other areas of the body.

Is MRI right for you?

A full body MRI scan can be used as part of a general health check-up to provide you with insights into your current health status.

This may be particularly important if you have a family history of certain health conditions, such as prostate cancer or bowel cancer, or if you are concerned that you have risk factors for other health conditions.

An annual MRI scan can be a helpful tool as part of your preventative healthcare. By getting ahead of any potential health problems, you can take proactive steps to avoid ill health or get treatment before symptoms develop or become serious.

MRI can also provide peace of mind if you have unexplained symptoms by helping to uncover the underlying cause.

After your MRI, your doctor will explain your results. If something of concern has been detected, they will recommend further tests so you can receive an accurate diagnosis and explore your treatment options.

Guidelines for brain MRI scans

A brain MRI scan is usually only recommended if you have symptoms that suggest a brain injury or brain disease.

These symptoms include:

behavioural changes
changes in your cognitive (thinking) abilities
imbalances in hormones whose levels are controlled by certain parts of the brain
persistent, severe headaches, dizziness and/or fatigue
seizures
hearing loss or vision loss that cannot be explained by routine hearing and vision tests.

During your brain MRI scan, you will be slid into the MRI scanner head first and in most cases, your whole body will not need to go into the MRI machine. A brain MRI scan usually takes 30–60 minutes.

Your next steps for MRI

If you are concerned about unexplained symptoms or want the peace of mind of knowing your current health status, an MRI scan can help.

You can speak to your doctor about whether an MRI scan will be useful and about advances in MRI technology available to investigate your areas of concern.

However, at Vista Health, you do not need to wait on a referral from a doctor to access MRI. You can self-refer for your MRI scan and have your scan at one of our conveniently located scanning facilities.

After your scan, you will receive a comprehensive report with insights into any findings that you can follow up on with your GP or with one of our Vista Health private GPs. You can then make more informed health decisions to protect your future.

To get started, book your private MRI scan with Vista Health today and make your health a priority.