A Closer Look

Powerful MRIs at a new on-campus facility are enabling Penn State researchers to examine everything from which plants have the most potential as fuel to how the human brain works.

by Alexander Gelfand
The Penn Stater
January/February 2011

THE PRINCIPLE BEHIND A MEDICAL MRI SCAN IS simple, even if the technology isn't: You lie down inside a giant tube, where you are simultaneously bathed in a powerful magnetic field and bombarded by radio waves. The electromagnetic signals your body generates in response are used to make a detailed image of your innards.

The same principle underlies the MRI scans produced at Penn State's new Social, Life, and Engineering Sciences Imaging Center, which takes up the entire ground floor of Chandlee Laboratory. But the researchers who come to SLEIC from across campus aren't looking to diagnose a slipped disc or torn rotator cuff. They're investigating things like how liquids move through the bodies of rats and which parts of the brain are active in binge drinkers.

The scanners are more powerful than the ones typically used in medicine. The MRIs most commonly found in hospitals, says Rick Gilmore, a psychology faculty member and SLEIC's acting director, usually have a magnetic field strength, measured in Teslas, of 1.5. The SLEIC scanners, by contrast, range from three Teslas (3T) for human subjects to two "high-field" machines, 7T and 14.1T, for small animals. (There's no evidence that these "high-field" machines are dangerous to people or animals, but their tubes are too small to accommodate anything much bigger than a cat.) The 14.1T MRI is one of only a handful in the United States.

The 3T machine is SLEIC's newest, operational since February 2009. It can do high-resolution anatomical studies, helping researchers understand, for example, how the structure of the ankle affects an athlete's ability to run fast, or why older adults lose mobility—things that previously could have been studied only by doing surgery. It can also take detailed pictures of fine structures in the brain, or detect heightened levels of oxygen-rich blood in particular areas—a sign of increased neurological activity. And that opens the door to all manner of research.

Neuroscientists like Gilmore, for example, use the 3T scanner to build detailed anatomical maps of people's brains. They then have those same subjects lie in the scanner while doing particular tasks, such as clicking a mouse in response to images on a computer screen, while the scanner maps brain function. By combining the two maps, scientists can understand where cognition occurs, and how the brain responds to stimuli.

Gilmore uses this kind of functional MRI to study brain activity among college students who are at increased risk of alcohol disorders like binge drinking—research that may ultimately lead to better methods of prevention. Psychology faculty member Stephen Wilson researches why it's so hard to quit smoking—and is working to develop better strategies for avoiding relapse.

The larger magnets in the 7T and 14.1T machines can generate high-resolution movies by taking multiple scans per second, and can detect the electromagnetic signatures of specific atoms in the body. Research associate Thomas Neuberger has used them to study the way in which liquids move through the guts of rats—information that could help scientists design drugs that will move more efficiently through human digestive systems. Researchers have also used these super-scanners to correlate the onset of stroke to increased levels of sodium atoms in animals' brains, which could help diagnose the disease in human patients.

The MRIs in Chandlee can be useful not just clinically, but ecologically as well: They can detect the hydrogen atoms in fat, allowing researchers to identify the fattiest—and therefore the most high-energy—sources for plant-based biofuels.

Better living through magnetic imaging. Now that's a pretty picture.

Copyright ©2011 Alexander Gelfand

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