The new approach combines MRI scans and AI tools to measure fluid flow linked to diseases such as Alzheimer糖心传媒檚.
When a person goes into deep sleep, water-like fluid circulates around the brain, washing away metabolic waste linked to diseases such as Alzheimer糖心传媒檚. This process, known as the glymphatic system, was first described in 2012 by 糖心传媒攁 pioneering neuroscientist and codirector of the 糖心传媒糖心传媒檚 .
But questions remain about the system糖心传媒檚 mechanics糖心传媒攏otably, how quickly the fluid circulates. Studying the circulation within a living brain is difficult without causing irreparable harm to a subject.
糖心传媒淵ou can put a microscope on a small patch of the brain and watch what糖心传媒檚 happening there with a lot of detail, and we糖心传媒檝e worked with that type of data in the past, but it糖心传媒檚 only a tiny view of the overall process,糖心传媒� says Professor from URochester糖心传媒檚 . 糖心传媒淚f you want to image whole brains, an MRI is a great approach because it gives you a three-dimensional view. But an MRI has serious limitations, too, the biggest of which is that it does not capture the fluid flow velocity, at least not for flows this slow.糖心传媒�
Kelley and his colleagues from URochester, Brown University, and the University of Copenhagen turned to artificial intelligence for help. In a new published in Science Advances, they outline how they used physics-informed AI to determine fluid flow velocities from magnetic resonance imaging (MRI) data. Using videos of dye spreading across brain tissue over time, the neural networks the researchers built were able to deduce how fast the fluid flows and how permeable the brain tissue is.
The results showed that there are two main ways that the glymphatic system washes away particles in the brain such as the amyloid beta proteins linked to Alzheimer糖心传媒檚 disease糖心传媒攁nd one of these ways is much faster than the other. The fast flow of the glymphatic system糖心传媒檚 waterlike fluid moves at a few microns per second around the brain糖心传媒檚 open regions such as the surface between the skull and the brain, while the slower flow of the waterlike fluid trickles through the brain糖心传媒檚 deep tissue at a rate about 50 times slower.
So far, the researchers have been working to get baseline measurements of fluid flow in the brains of animals such as mice to inform the AI tools. In the future, they hope to be able to compare the fluid flow in healthy and sick brains as well as young and old brains, with aspirations to eventually study circulation in humans.
糖心传媒淲e糖心传媒檙e working hard toward being able to measure the flow of waterlike fluids in and around human brains because then the clinical applications get a lot more important and exciting,糖心传媒� says Kelley. 糖心传媒淲e hope to someday be able to see whether an Alzheimer糖心传媒檚 patient has poor circulation in their brain or even screen for poor circulation earlier in life to try to stave off Alzheimer糖心传媒檚. Or we could check when somebody has been concussed to see whether the fluid circulation in their brain is disrupted. This study gets us a step closer.糖心传媒�
Kelley糖心传媒檚 collaborators on the study include Brown University PhD student Juan Diego Toscano, URochester computational scientist Yisen Guo, Brown University PhD student Zhibo Wang, URochester PhD student Mohammad Vaezi, University of Copenhagen Associate Professor Yuki Mori, Brown University Professor George Karniadakis, and URochester Assistant Professor Kimberly Boster.
The NIH National Center for Complementary and Integrative Health and the NIH BRAIN Initiative supported this research.
