On the UTILISE project we are collecting MRI scans of some participant’s brains, but what does that really mean, and why are we doing it?
MRI stands for “Magnetic Resonance Imaging”. MRI machines use a strong magnetic field and radio waves to form high-contrast pictures of soft tissue in the body, so it’s perfect for looking at the brain.
MRI scans do not involve radiation and is very safe for most people. However, because it uses a large magnet, MRI is not safe for people with metal in their bodies, for example pace makers, metal plates or titanium clips.
We conduct our scans at BUCNI (Birkbeck UCL Centre for NeuroImaging) over at 26 Bedford Way. When a participant arrives, we take them to the scanner and ask some safety questions. Once everyone is happy, it is important to remove all metal! This means making sure all jewellery is off, pockets are emptied, glasses are removed, etc. We then tape a vitamin capsule to the left side of the head, as this will glow bright white on the pictures and let us know we’re referring to the correct side of the brain.
The scanner is like a big tube, with a bed in the middle. We give the participant ear plugs (because the scanner is very noisy!) and help them to lay comfortably on the bed, with a blanket and some soft padding around the head. Once we’ve lined everything up, the bed slides into the tube, head first, but not all the way.
When someone is in the scanner, we can still communicate. They have a buzzer so they can let us know if they want to get out, and there is a two-way intercom system so we can talk them through the process. Whilst we are scanning, the most important thing is to keep nice and still, so that we take clear pictures. Some people can find it quite relaxing.
We are doing two kinds of scan: structural and functional. What’s the difference?
Structural scans are ‘still’ pictures of the brain, which show us where the stroke is. Hundreds of pictures are taken in ‘slices’ and stitched together to create a 3D representation of the brain. Using these pictures, we can identify which regions have been lesioned. This is important because it may help us to understand to whether lesion pattern is related to whether or not someone improves, or to what extent they improve, after therapy. Usually, people with aphasia have damage to the left side of the brain.
Resting state functional scans are like little videos and allow us to see how different brain areas talk to each other by looking at oxygenated blood flow. We are interested in whether patterns of connectivity are different before and after therapy.
This video shows a structural scan of one of the research team’s brains (non-lesioned), moving through the slices in each view: from front to back (coronal plane), from side to side (sagittal plane), and from top to bottom (axial plane).