Warming up for magnetic resonance imaging

Higher temperatures yield tunable, supersensitive Hyper-CEST MRI

In xenon biosensors, the xenon atoms are temporarily held inside cryptophane cages. Attached linkers include a group to render the sensor soluble plus a targeting unit customized to seek out... Click here for more information.

BERKELEY, CA -- Standard magnetic resonance imaging, MRI, is a superb diagnostic tool but one that suffers from low sensitivity, requiring patients to remain motionless for long periods of time inside noisy, claustrophobic machines. A new MRI method, much faster, more selective -- able to distinguish even among specific target molecules -- and many thousands of times more sensitive, has now been developed by researchers at the Department of Energy's Lawrence Berkeley National Laboratory and the University of California at Berkeley.

The key to the new technique is called "temperature-controlled molecular depolarization gates." It builds on a series of previous developments in MRI and the closely related field of nuclear magnetic resonance, NMR (which instead of an image yields a spectrum of molecular information), by members of the laboratories of Alexander Pines and David Wemmer at Berkeley Lab and UC Berkeley. Pines is the Glenn T. Seaborg Professor of Chemistry at the University of California at Berkeley and a senior scientist in Berkeley Lab's Materials Sciences Division. Wemmer is Professor of Chemistry at UC Berkeley and a member of Berkeley Lab's Physical Biosciences Division.

The technique was developed by a team led by Leif Schröder of Berkeley Lab's Materials Sciences Division, and including Lana Chavez, Tyler Meldrum, Monica Smith, and Thomas Lowery, all past or present members of the Pines and Wemmer labs; the researchers outline their results in the international edition of the journal Angewandte Chemie.

"The new method holds the promise of combining a set of proven NMR tools for the first time into a practical, supersensitive diagnostic system for imaging the distribution of specific molecules on such targets as tumors in human subjects," says lead author Schröder, "or even on individual cancer cells."

In the technique known as "temperature-controlled molecular depolarization gates, " an atom of hyperpolarized xenon from the pool at left enters a cryptophane cage, center, which is part of a biosensor... Click here for more information.

Laying the groundwork: hyperpolarization and cryptophane biosensors lead to Hyper-CEST MRI