The technique, developed by Northwestern University researcher David D. McPherson, M.D., and colleagues with a $2.3 million grant from the National Institutes of Health, uses ultrasound energy to create microbubbles inside specially treated liposomes and then direct the liposomes to specific targets, such as atherosclerotic plaques or blood clots, in the coronary arteries and other arteries in the body, including those to the brain.

Once they reach their target in the arteries, the echogenic liposomes, or ELIPs, produce an acoustic shadow that improves ultrasound's ability to visualize and diagnose the extent of plaques or clots within the arteries.

Further, the ELIPs can be treated to also encapsulate certain drugs, such as antibiotics or thrombolytic (clot-busting) drugs or gene therapy, which, with the help of ultrasonic pulses, can be released at the site of a plaque or a clot or into living cells. This is caused by cavitation, the ability of the ultrasound to increase the energy of the microbubble, which then opens the cell membrane and allows drugs to enter.

McPherson, who is Lester B. and Frances T. Knight Professor of Cardiology and professor of medicine at the Feinberg School of Medicine at Northwestern University, believes that the ultrasound technique may further understanding of how atherosclerotic plaques develop and grow, as well as enhance more than tenfold scientists' ability to target drug or gene therapy toward specific atherosclerotic components or affected tissue without damaging cells.

"The science of ultrasound, in addition to its imaging capability, also lies in its biologic effects. By harnessing the physical effects of ultrasound, we can physiologically evaluat
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Contact: Elizabeth Crown
e-crown@northwestern.edu
312-503-8928
Northwestern University
22-Jan-2004