Tweaking MRI method may help spot heart problems earlier

Researchers including an Indian origin scientist have suggested that a new MRI method to map creatine at higher resolutions in the heart may help clinicians and scientists find abnormalities and disorders earlier than traditional diagnostic methods.

Creatine is a naturally occurring metabolite that helps supply energy to all cells through creatine kinase reaction, including those involved in contraction of the heart. When heart tissue becomes damaged from a loss of blood supply, even in the very early stages, creatine levels drop.

The team, led by Ravinder Reddy, PhD, professor of Radiology and director of the Center for Magnetic Resonance and Optical Imaging at Penn Medicine, found that imaging creatine through CEST MRI provides higher resolution compared to standard magnetic resonance spectroscopy (MRS), a commonly used technique for measuring creatine. However, its poor resolution makes it difficult to determine exactly which areas of the heart have been compromised.

To demonstrate CEST's ability to detect heart disease, the researchers applied the creatine CEST method in an MRI scanner, in healthy and infarcted myocardium (muscle tissue in heart) in large animals.

In the process, the nuclear magnetization of amine (NH2) creatine protons is saturated by a radiofrequency pulse from the MRI. After the exchange with water, the degree of saturation is observed as the water signal drops, and thus the concentration of creatine becomes apparent.

The team showed that the creatine CEST method can map changes in creatine levels, and pinpoint infarcted areas in heart muscle tissue, just as MRS methods can. However, they found, CEST has two orders of magnitude higher sensitivity than MRS. That advantage could help spot smaller damaged areas in the heart missed by traditional methods, the authors say.

A new study has been published online in journal Nature Medicine.