Doing an MRI scan

What is an MRI?

MRI stands for magnetic resonance imaging: it is a technique to create two- or three-dimensional images of the brain using magnetic fields (but no X-rays and no radioactive tracers).

fMRI stands for functional MRI: it is a special MRI technique that measures the changes in oxygen in the brain blood vessels. Then it creates an image upon the standard MRI image showing which parts of the brain activate (increase in oxygen) or deactivate (decrease in oxygen) when the person is doing one action compared to another.

Example of an fMRI recording of brain activity on a 2D MRI image of a brain

The MRI uses an MRI scanner, a large magnetic tube with an opening so wide a person can comfortably lie inside.

Photo of an MRI scanner. The participant lies down on the scanner table, then the radiographer slides the table into the scanner tube.

What happens during an MRI test?

Set up

Checking you are fit for an MRI scan: Either before the appointment or right at the beginning you will have to complete one or several forms with questions to make sure you are fit to go into the MRI scanner. If you have questions, please ask the researcher, or, if you are at the appointment, the radiographer. They will be able to help you.

Getting changed and ready for the MRI scan: You will then go to a changing room where you will leave your belongings and take off all your metal items (jewellery, piercings, watch…). If you are wearing clothes that have metal, you will have to change into a hospital gown. If you none of your clothes have metal, you may be able to wear them inside the scanner. The radiographer will tell you what you should remove. If you are wearing glasses and the session involves mental tasks, you might have to change your glasses for MRI-friendly plastic glasses, so make sure you know your prescription.

Settling on the MRI scanner table: When you are ready, the radiographer will take you to the MRI scanner room. You will lie on the scanner table, and the radiographer will help you get comfortable, possibly giving you a cushion for your knees or a blanket for warmth. They will give you special earplugs to block the noise. These special earplugs have earphones inside, so that you can hear the radiographers when they need to speak to you during the session. The radiographer will also give you an emergency press button to use if you have a problem during the session. Finally, the radiographer will place a head rest around your head for you not to move it too much during the session.

If the session includes an fMRI task: If the session involves mental tasks, you might also be given special handles with press button that you will use to do the mental tasks. The researcher will explain to you if you need them, and if so, how you will have to use them. Finally, the radiographer will place a special head frame with a mirror for you to be able to see the large computer screen placed behind the scanner.

Photo of a researcher explaining a particitant how to use the special handles to complete an fMRI task.

Once everything is ready, the radiographer will slide the scanner table inside the scanner. If you have any question, please do ask the researcher or the radiographer.

Photo of a researcher helping a participant settle on the scanner table.

During the MRI scan

The scanning session can last 10 minutes to 1h, depending on the number of measures and tasks. The researcher and the radiographer will let you know when each new measure starts, and will tell you what to do. For example, there might be a few minutes when you will be asked to keep your eyes open, staring at a fixed point (of course you will be allowed to blink).

If the session includes mental tasks, the researcher will tell you when they start and what to do during the tasks. If you have any question, please do ask the researcher or the radiographer.

The scanner will make loud noises. The noises change depending on the king of measures the scanner is doing. Unfortunately, there is no way to fully block these noises. If you think these loud noises might be particularly uncomfortable for you, please let the researcher and the radiographer know, they may be able to help you with another headphone.

After the MRI scan

Once the scanning session is over, the radiographer will let you know through the earphones, but don’t try to get out of the scanner by yourself. The radiographer will immediately come and slide the scanner table out of the scanner, remove all the equipment, and help you get down the table. Then you will go back to the changing room to change back into your own clothes and get your belongings. Once this is done, you will meet again the researcher who will let you know about the next step of the research project, if there are any.

How to prepare for an MRI?

General: As mentioned above, there are a few things you have to do before an MRI scanner. First, it is essential that you complete any pre-appointment form checking whether you are fit to have an MRI scan. If you are wearing glasses and the session involves mental tasks, you might have to change your glasses for MRI-friendly plastic glasses during the session, so make sure you know your prescription. Except if the researcher says otherwise, there is nothing else you especially have to do to prepare. For example, except if the researcher says otherwise, there is no need for you to stop any medication you might be taking.

Preparing for sensory difficulties (tight space and noise): If you think the tight space and/or the noise may be problematic, please do tell the researcher before the appointment, they will do their best to help you prepare. They may be able to show you a mock MRI scanner for you to practice lying down inside the tube, or they may be able to find different headphones to block out the noise.

Photo of the mock MRI scanner at the Kennedy Tower. You can prepare for your MRI scan by practicing lying down in this mock scanner.

Here is an example of A Visit to the MRI guide (with photos) written by Bérengère Digard for the people who took part in her PhD research. Please feel free to read it to learn more about MRI appointments.

Entrance of the Clinical Research Imaging Centre, where MRI appointments take place.