Imagine a photographer shooting a tall building, but instead of a single frame, they take a series of shots while moving the camera in a spiral from top to bottom. This approach captures more detail in less time, but the images can come out blurry. A similar challenge faces MRI machines when they need to quickly image the brain.
Scientists have proposed a new scanner trajectory called LOTUS. Instead of straight lines, the scanner moves along a three-dimensional spiral that gently sways from side to side. It's like a bee circling a flower, gradually getting closer to the center. This motion captures several 'slices' of the brain at once, as if the photographer were shooting not just one floor of the building but several at a time.
Fast scanning is crucial for diffusion MRI, which shows how water moves along nerve fibers. It's like a road map of the brain: you can see where pathways are damaged. But if you scan too quickly, the image gets noisy, like a photo taken in the dark. The new spiral trajectory helps reduce that noise without sacrificing speed.
The researchers tested the method on a computer model and two volunteers. They found that LOTUS reduces distortion by 20–31% compared to other approaches, especially when the brain is scanned with high acceleration. The more slices captured simultaneously, the more noticeable the advantage. This means that in the future, diffusion MRI could be faster and more accurate, helping doctors see the brain's structure better.
Diffusion MRI measures how water molecules move in the brain. Along nerve fibers, water moves freely, like through a pipe, but across them, it moves slowly, like through a sponge.
In the movie 'Total Recall,' the hero's brain is scanned to record memories. Fast and precise MRI like LOTUS brings that science fiction closer to reality.