Take heart. New test reduces risk for patients

Health-care professionals may soon have a clearer ‘window’ into heart disease while offering a near risk-free testing option to more than half a million Canadians, according to a recent study.

A team of international researchers, including Medical Biophysics professor Frank Prato, recently developed a new method of testing for the presence of heart disease – cardiac functional MRI (cfMRI) – one that does not require needles or chemicals being injected into the body.

Currently, diagnostic tests measure blood flow to the heart by injecting radioactive chemicals or contrast agents that change the MRI signal when disease is present. As there are risks associated with the procedure, it is not recommended for a variety of patients, including those with poor kidney function. Nevertheless, more than 500,000 tests are performed each year in Canada.

This newest method, however, uses repeated exposure to carbon dioxide to test how well the heart’s blood vessels are working in delivering oxygen to the muscle. A breathing machine then changes the concentration of carbon dioxide in the blood, which results in a change in blood flow to the heart in healthy bodies, but no change when disease is present.

“The method eliminates the existing risks and can be used on all patients,” said Prato, Assistant Director (Imaging) at Lawson Health Research Institute.

“Our discovery shows we can use MRI to study heart muscle activity. We’ve been successful in using a pre-clinical model. Now, we are preparing to show this can be used to accurately detect heart disease in patients.”

In addition to studying coronary artery disease, Prato said this new method could be used in other cases where blood flow to the heart is affected, including post-heart attack or following treatments for cancer.

With its minimal risk, this new method can be safely used multiple times with the same patient to better select the right treatment and find out early on if it is working.

“With this new window into how the heart works, we have a lot to explore when it comes to the role of oxygen in health and disease,” Prato said.

The research team included colleagues from Lawson, Cedars-Sinai Medical Center, the University of California, King’s College (U.K.), the University of Edinburgh (U.K.); University Health Network, the University of Toronto, and Siemens Healthineers.

The study, Accurate needle-free assessment of myocardial oxygenation for ischemic heart disease in canines using Magnetic Resonance Imaging, was published in the May 29 edition of Science Translational Medicine.