Powerful Magnet Attracts Support for Imaging

Vanderbilt researchers have received a five-year, $5.7 million federal grant to study the human brain using one of the world’s most powerful magnets. The National Institute of Biomedical Imaging and Bioengineering grant represents the renewal of a Bioengineering Research Partnership grant originally awarded for $4 million in 2002 to study “integrated functional imaging of the human brain.”

But “it’s a complete change of direction” this time, says John Gore, the grant’s principal investigator and director of the Vanderbilt University Institute of Imaging Science. “We want to focus on the challenges of the highest field in human imaging.”

The grant will support development of “high field” magnetic resonance imaging and spectroscopy using the institute’s 7 Tesla scanner, one of only 13 in the world being used in human studies.

One Tesla is roughly 20,000 times the strength of the magnetic field of the earth. Encased in 400 metric tons of steel, the 7 Tesla scanner can generate brain images down to the molecular level.

The magnet interacts with atoms, such as hydrogen, in body tissues so they will absorb energy from particular frequencies of radio waves, causing them to resonate. By measuring these magnetic effects, scanners can construct detailed images of structures in the body and also determine the levels of key compounds, including molecules that are involved in signaling in the brain.

More powerful magnets require the use of higher frequency radio waves, and generate bigger signals that can be used to increase the resolution — the detail — of the images. The 7 Tesla scanner, for example, can reveal tiny blood vessels in the brain that are beyond the resolving power of conventional scanners, and can bring the focus down to single columns of neurons.

Ultimately, high-field magnetic resonance and spectro-scopy may enable researchers to study the effects of drugs on a wide range of brain disorders, from chronic pain to Alzheimer’s disease, and to help develop new drugs.

Gore is Chancellor’s University Professor of Radiology and Radiological Sciences and Biomedical Engineering, and professor of molecular physiology, biophysics and physics.

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