If your doctor has referred you for an MRI scan, it means they need a detailed image of the inside of your body to help diagnose your condition. You may need an MRI if you have unexplained pain, swelling, or discomfort in a particular area, or if other imaging tests have not provided enough information. During an MRI, you will lie on a table that slides into a large tube-like machine that uses a strong magnetic field and radio waves to create detailed images of the inside of your body. The scan is painless and non-invasive, but it can be noisy, so you will be given headphones to listen to music or a radio station.
At Blackrock Health, we understand that waiting for diagnostic results can be stressful. That is why we offer fast access to our state-of-the-art facilities in Blackrock, Galway, Hermitage and Limerick. Across our three hospitals and our diagnostic clinic, we are committed to ongoing investment in imaging and lab tests. By offering some of the most advanced imaging and diagnostic technology, we aim to provide accurate and timely diagnoses. Our team of experts has the capacity and expertise to perform, analyse, and report results for a wide range of tests. This ensures that you can receive the highest possible standards of care and support. Whether you need routine tests or more urgent imaging, we aim to give you the reassurance of a result with the least possible delay.
Magnetic Resonance Imaging (MRI) is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body.
An MRI scanner is a large tube that contains powerful magnets. You lie inside the tube during the scan.
An MRI scan can be used to examine almost any part of the body, including the:
brain and spinal cord.
bones and joints.
heart and blood vessels.
internal organs, such as the liver, womb, or prostate gland.
The results of an MRI scan can be used to help diagnose conditions, plan treatments, and assess how effective previous treatment has been.
Blackrock Health use the referral criteria, ‘iRefer Guidelines, Making the Best Use of Clinical Radiology’. These guidelines are considered when requesting a diagnostic radiology/nuclear medicine examination.
What happens during an MRI scan?
During an MRI scan, you lie on a flatbed that is moved into the scanner.
Depending on the part of your body being scanned, you will be moved into the scanner either headfirst or feet first.
The MRI scanner is operated by a radiographer, who is trained in carrying out imaging investigations.
They control the scanner using a computer, which is in a different room, to keep it away from the magnetic field generated by the scanner.
You will be able to talk to the radiographer through an intercom and they will be able to see you on a television monitor throughout the scan.
At certain times during the scan, the scanner will make loud tapping noises. This is the electric current in the scanner coils being turned on and off.
You will be given earplugs or headphones to wear.
It is particularly important to keep as still as possible during your MRI scan.
The scan lasts 15 to 90 minutes, depending on the size of the area being scanned and how many images are taken.
How does an MRI scan work?
Most of the human body is made up of water molecules, which consist of hydrogen and oxygen atoms.
At the centre of each hydrogen atom is an even smaller particle called a proton. Protons are like tiny magnets and are extremely sensitive to magnetic fields.
When you lie under the powerful scanner magnets, the protons in your body line up in the same direction, in the same way that a magnet can pull the needle of a compass.
Short bursts of radio waves are then sent to certain areas of the body, knocking the protons out of alignment.
When the radio waves are turned off, the protons realign. This sends out radio signals, which are picked up by receivers.
These signals provide information about the exact location of the protons in the body.
They also help to distinguish between the diverse types of tissue in the body, because the protons in several types of tissue realign at different speeds and produce distinct signals.
In the same way that millions of pixels on a computer screen can create complex pictures, the signals from the millions of protons in the body are combined to create a detailed image of the inside of the body.
An MRI scan is a painless and safe procedure. You may find it uncomfortable if you have claustrophobia, but most people are able to manage it with support from the radiographer.
Going into the scanner feet first may be easier, although this is not always possible.
Extensive research has been carried out into whether the magnetic fields and radio waves used during MRI scans could pose a risk to the human body.
No evidence has been found to suggest there is a risk, which means MRI scans are one of the safest medical procedures available.
But MRI scans may not be recommended in certain situations. For example, if you have a metal implant fitted, such as a pacemaker or artificial joint, you may not be able to have an MRI scan.
They are also not usually recommended during pregnancy.
Metal implants or fragments:
Having something metallic in your body does not necessarily mean you cannot have an MRI scan, but it is important for medical staff carrying out the scan to be aware of it.
They can decide on a case-by-case basis if there are any risks, or if further measures need to be taken to ensure the scan is as safe as possible.
For example, it may be possible to make a pacemaker or defibrillator MRI-safe, or to monitor your heart rhythm during the procedure.
You may need to have an X-ray if you are unsure about any metal fragments in your body.
Examples of metal implants or fragments include:
a pacemaker – a small electrical device used to control an irregular heartbeat
an implantable cardioverter-defibrillator (ICD) – a similar device to a pacemaker that uses electrical shocks to regulate heartbeats
metal plates, wires, screws, or rods – used during surgery for bone fractures
a nerve stimulator – an electrical implant used to treat long-term nerve pain
a cochlear implant – a device like a hearing aid that is surgically implanted inside the ear
a drug pump implant – used to treat long-term pain by delivering painkilling medication directly to an area of the body, such as the lower back
brain aneurysm clips – small metal clips used to seal blood vessels in the brain that would otherwise be at risk of rupturing (bursting)
metallic fragments in or near your eyes or blood vessels (common in people who do welding or metalwork for a living)
prosthetic (artificial) metal heart valves
penile implants – used to treat erectile dysfunction (impotence)
eye implants – such as small metal clips used to hold the retina in place
an intrauterine device (IUD) – a contraceptive device made of plastic and copper that fits inside the womb
artificial joints – such as those used for a hip replacement or knee replacement
dental fillings and bridges
tubal ligation clips – used in female sterilisation
surgical clips or staples – used to close wounds after an operation
Some tattoo ink contains traces of metal, but most tattoos are safe in an MRI scanner. Tell the radiographer immediately if you feel any discomfort or heat in your tattoo during the scan.
Sometimes an injection of intravenous contrast (‘dye’) is required for certain scans. You will be informed if this is necessary, and the radiographer will explain the procedure on the day of your scan.
Specialist MRI Scans
At certain locations, Blackrock Health also carry out Cardiac MRI scans for our heart patients. You can learn more about this here.
How do I get this?
You will need a referral letter from your GP or consultant before you make an appointment. Please see our Request Appointment Form here.
Is this insured?
Not all services are covered by health insurance. To find out if you're covered, please check your health insurance before your visit. You can do this on our health insurance Cover Check page here, or by contacting your health insurer.
How do I pay?
If you do not have health insurance or your health plan does not cover the full cost, you will need to pay the balance due before your treatment or procedure. You may be able to claim back some fees on your insurance. To pay an excess not covered by your insurance or any other inpatient fees, please visit our payment page here. If you have any queries about paying for your care, please contact the finance team in your hospital.