Just as importantly, the researchers said, this technology can easily be applied to existing MRI machines, since the advances reported by the Duke team do not involve new hardware, but are rather the result of new conceptualization of the technology.

MRI uses harmless magnetic fields and radio-frequency signals to image tissues in the body. Basically, the magnetic fields cause hydrogen nuclei, or protons, that are part of water molecules in tissue to align. Pulses of radio frequency waves perturb this alignment, and the molecules give off telltale signals as they lose energy. The signature of such water molecules differs according to the tissue, providing the contrast that is a key to MRI's ability to sensitively image tissues.

The new approach, called global coherent free precession (GCFP), allows researchers to selectively "tag" protons within the water of blood cells with radio frequency waves as they pass through the plane of the MRI scan. Since all other tissues surrounding the blood do not pass through the scanner's plane, they are not tagged, leaving images solely of the blood as it moves downstream through the vessel.

The results of the Duke experiments, which will appear in the May issue of the journal Nature Medicine, were posted early on-line April 4, 2004.

Lead researcher Robert Judd, Ph.D., co-director of the Duke Cardiovascular Magnetic Resonance Center, recently received a grant from the National Institutes of Health to further study the MRI physics of the new phenomenon. Judd collaborated with Wolfgang Rehwald, Ph.D., a physicist with Siemens Medical Systems, manufacturer of the MRI equipment, as well as Duke researchers Raymond
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Contact: Richard Merritt
merri006@mc.duke.edu
919-684-4148
Duke University Medical Center
4-Apr-2004