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Tuesday, January 11, 2011

Faster brain scans

A team of researchers from the University of Minnesota, Universities of California Berkeley and San Francisco, Washington University and Oxford, as well as from Advanced MRI Technologies has reduced the time required for full 3D fMRI brain scans over five fold.

Briefly, functional magnetic resonance imaging (fMRI) uses pulses of radio waves to measure the amount of oxygen being delivered to specific neurons. Neurons that are actively firing require more oxygen than those that are quiescent. Therefore, by using fMRI, researchers can actually watch people think. Naturally, the faster images can be taken, the more accurate the picture of how people are using their brains.

The team combined two novel techniques, each of which reduces scan time over conventional means. The first technique was to send the radio pulses out in multiple bands. The second was to make use of echoes to multiply the amount of information gained from each pulse. Taken together, these two innovations allow scans to be made in less than half a second, rather than in the two or three seconds required by conventional methods.

Caption: The new technique accelerates diffusion MRI as well as functional MRI. The colored tracks show the direction of nerve fiber bundles, providing a 3-D image of the axonal pathways in the white matter (cortex) of a resting human brain. A normal structural cross sectional image of the brain (fMRI) bisects the diffusion 3-D fibertrack image. The entire 3-D image was scanned in 8.5 minutes instead of 30 minutes.

Credit: David Feinberg

Besides helping doctors map specific brain disorders, the researchers are hopeful that this increase in processing speed will be a major boon for the Human Connectome Project. The goal of this project is to map every neural connection in the human brain, and thereby understand what makes us who we are. You can watch a video explaining this here.