Scientists at Johns Hopkins have developed the first precise, noninvasive means of measuring a chemical in the heart tied to the extent of muscle damage from a heart attack.
The test pinpoints in injured heart tissue depleted concentrations of creatine, a molecule that provides energy to the muscle. The new test works using commonly available magnetic resonance imaging scanners, which will make the technique potentially widely available.
"Until now, there were no methods for noninvasively assessing local creatine levels in the normal and diseased human heart. Now we can observe and measure total creatine throughout the human heart and its reduction in infarcted, or dead heart tissue," says Robert G. Weiss, M.D., associate professor of medicine and cardiology and an author of the report on the development published in the March 7 Lancet .
The new test, developed with funding from the National Institutes of Health and the American Heart Association, identifies and measures creatine concentrations using magnetic resonance spectroscopy (MRS) in different regions of the heart. The image of each region to be examined with MRS is first obtained by MRI during the same examination.
"MRI allows us to see only the structure of the heart," says Paul A. Bottomley, Ph.D., professor of radiology and co-author of the paper. "But in combination with MRS, we can investigate specific regions on the MRI images and measure the concentration of creatine there with pinpoint accuracy. We can even see heart muscle damage in the back of the heart wall, a difficult area to observe with prior imaging techniques."
In clinical studies of the new "creatine depletion" test, Bottomley and
Weiss, evaluated 10 healthy volunteers and 10 patients with prior heart attacks,
checking for the amount of creatine in tissues of the septum, the wall
separating the right and left ventricles or main pumping chambers of the heart;
and in the
Contact: Marc Kusinitz
Johns Hopkins Medical Institutions