There’s plenty we don’t yet know about the brain, but at least we have a fairly decent arsenal of scientific tools in which to examine it without physically poking it. Now, thanks to Stanford University, the University of Auckland (UoA), and the Stevens Institute of Technology, we have another, mind-bogglingly high-resolution version tool in the box.
As first spotted by Science News, and as revealed in a paper published in Magnetic Resonance in Medicine, the team used something called “amplified MRI” to catch and essentially zoom in on the tiniest movements in the brain. As you can see in the gif below, it literally jiggles with every heartbeat, which is simultaneously unnerving, fascinating, and scientifically spectacular.
These motions are incredibly fine, by the way: less than the width of a single human hair. Normal MRI techniques can’t really pick them up in any detail, but in order to understand why, we probably need a quick recap on what MRI actually is.
Magnetic resonance imaging (MRI) machines are, by all accounts, marvelous things. By applying a strong magnetic field to the water molecules in your body – or brain, of course – the protons attached to the hydrogen atoms line up, much like the needles on a compass.
Altogether, this creates a signal that’s easy to measure by technicians. This non-invasive, harmless imaging technique allows us to see what’s happening inside the brain in real time.
An oft-used variant is functional MRI (fMRI) scanning, which can, for example, track the blood in your brain. As it turns out, hemoglobin – the oxygen-carrying component of your blood – has different magnetic properties depending on how oxygenated it is.
fMRI can pick this up, and determine how blood is moving or changing in the brain. By doing this, researchers can see which parts are currently more active at one time than the other, depending on what the person is thinking about or doing.
The resolution on these techniques is limited, though, which is why the international team featured here decided to try something new.
Back in 2016, a team led by Samantha Holdsworth and Mahdi Salmani Rahimi at Stanford described something rather remarkable in a brand-new paper of theirs: Namely, that they could build on pre-existing MRI tech to amplify the motion of blood and spinal fluid in the brain.
This represented the genesis of amplified MRI (aMRI), but Itamar Terem, Stanford University research assistant and first author on the latest paper, tweaked the technique to demonstrate that it could be put to clinical and diagnostic use.
The most current iteration of the tech involves attaching a pulsometer – a device that counts the heart beats per minute in a patient – so one could sync up the imaging with the blood every time it moves through the brain. At the same time, a pre-existing video magnification algorithm (first developed by a team at MIT) was tailored to match up with the MRI scans.
Combining both techniques together, Terem et al found that you could visualize the brain in its proper anatomic detail and scale while also more clearly seeing the movement of fluids up there. This is known as phase-based aMRI, and it's allowing us to observe the subtlest of brain tissue motions caused by the flow of blood and cerebrospinal fluid.
“We have succeeded in revealing small motions near the midbrain, spinal cord, cerebellum and even in areas such as the frontal lobe," Terem explained in an emailed statement.
So far, this is a proof-of-concept design, but they’ve already used it to clearly show differences between a control and a person with a brain disorder, Chiari malformation type I, which is typified by an unusually shaped cerebellum.
This is just the beginning. Holdsworth, now at the University of Auckland, explained that “aMRI may allow us to detect pathological brain and vessel motion due to diseases or disorders that obstruct the brain or block the flow of brain fluid.”
Clealry, this technique has the ability to revolutionize how we understand the biomechnical properties of the brain, so we suspect this won't be the last time you'll hear about it. Watch this space.
Updated to reflect comments by the Universities of Stanford and Auckland