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Brain in Motion

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Credit: Itamar Terem, Stanford University, Palo Alto, CA, and Samantha Holdsworth, University of Auckland, New Zealand

Though our thoughts can wander one moment and race rapidly forward the next, the brain itself is often considered to be motionless inside the skull. But that’s actually not correct. When the heart beats, the pumping force reverberates throughout the body and gently pulsates the brain. What’s been tricky is capturing these pulsations with existing brain imaging technologies.

Recently, NIH-funded researchers developed a video-based approach to magnetic resonance imaging (MRI) that can record these subtle movements [1]. Their method, called phase-based amplified MRI (aMRI), magnifies those tiny movements, making them more visible and quantifiable. The latest aMRI method, developed by a team including Itamar Terem at Stanford University, Palo Alto, CA, and Mehmet Kurt at Stevens Institute of Technology, Hoboken, NJ. It builds upon an earlier method developed by Samantha Holdsworth at New Zealand’s University of Auckland and Stanford’s Mahdi Salmani Rahimi [2].

In the video, a traditional series of brain scans captured using standard MRI (left) make the brain appear mostly motionless. But a second series of scans captured using the new technique (right) shows the brain pulsating with each and every heartbeat.

As described in the journal Magnetic Resonance in Medicine, the team started by measuring the pulse of a healthy person. They synchronized the pulse with MRI images of the person’s brain, stitching the scans together to create a sequential video. Their new MRI approach then relies on a special algorithm developed by another group to magnify the subtle changes.

The new report demonstrates application of the technique to MRI scans of a healthy person and someone with structural abnormalities of the skull and the brain’s cerebellum known as Chiari malformations. Remarkably, those amplified MRI images revealed obvious differences in brain motion. The researchers also showed in another investigation which parts of the brain move the most.

The researchers hope this new approach will help physicians capture potentially important changes in the brains of people with conditions such as hydrocephalus (“water on the brain”), which influence brain pressure and motion. One thing is already clear: we’ve never seen the brain quite like this before.

References:

[1] Revealing sub-voxel motions of brain tissue using phase-based amplified MRI (aMRI). Terem I, Ni WW, Goubran M, Rahimi MS, Zaharchuk G, Yeom KW, Moseley ME, Kurt M, Holdsworth SJ. Magn Reson Med. 2018 May 30.

[2] Amplified magnetic resonance imaging (aMRI). Holdsworth SJ, Rahimi MS, Ni WW, Zaharchuk G, Moseley ME. Magn Reson Med. 2016 Jun;75(6):2245-2254.

Links:

Kurt Lab (Stevens Institute of Technology, Hoboken, NJ)

Samantha Holdsworth (University of Auckland, New Zealand)

NIH Support: Eunice Kennedy Shriver National Institute of Child Health and Human Development