November 13, 1995
Media Contact: John D. Cramer
Phone: (410) 955-1534
Johns Hopkins scientists have developed a rapid nuclear magnetic resonance imaging (MRI) test that can identify animal heart cells that have died after blood flow stops and restarts, a finding that may eventually speed up diagnosis and treatment of heart attacks in people.
"The finding may be an early step toward developing a direct, non-invasive way to measure the extent of heart damage and may help guide surgical and drug therapies," says Raymond J. Kim, M.D., the study's lead author and a cardiology fellow. "Unlike stress tests and echocardiography, which are indirect, this test directly measures the damage."
The findings are to be presented Nov. 14 at the American Heart Association's 68th Annual Scientific Meeting in Anaheim, California. The study was supported by the National Institutes of Health.
In a heart attack, damage occurs when blood flow is blocked and again when it restarts, leaving dead heart cells with an abnormally high sodium concentration. Hopkins researchers theorized that MRI could detect these abnormal sodium levels in tissue, thus determining how much heart tissue had died as a guide to treatment, says Kim. To test the idea, researchers developed a fast MRI technique for imaging sodium atoms in rabbit hearts in seven minutes. With standard MRI techniques, the process takes about four hours. Microscopic and spectroscopic examination of the cells verified the new MRI results. Researchers are refining the new method and considering studies with humans and an expanded animal study to examine heart cells after blood flow stops but before the cells die.
Other researchers in the study were Joao A.C. Lima, M.D., graduate students Enn-Ling Kim and Scott B. Reeder, Elias A. Zerhouni, M.D., and Robert M. Judd, Ph.D.