Magnetic Resonance Imaging (MRI) offers an easier, faster and cheaper way to measure how the heart uses oxygen for both healthy patients and those with heart disease.

This new method called "cardiac functional MRI" or cfMRI doesn't require needles to inject chemicals into the body. Instead, cfMRI uses repeat exposure to carbon dioxide to test how well the heart's blood vessels are working to deliver oxygen to the muscles.

In this method, a breathing machine is used to change the concentration of CO2 in the blood. This change should result in a change in blood flow to the heart, which doesn't happen when heart disease is present. The cfMRI method reliably detects if these changes are present.

It was developed by an international team led by scientists from Lawson Health Research Institute in Ontario, Canada and Cedars-Sinai Medical Center in Los Angeles, California, which also became the first to show MRI can be used in this way.

"Our discovery shows that we can use MRI to study heart muscle activity," said Dr. Frank Prato, Lawson Assistant Director for Imaging. "We've been successful in using a pre-clinical model and now we are preparing to show this can be used to accurately detect heart disease in patients."

Reduced blood flow to the heart muscle is the top cause of death in the West. Existing diagnostic tests available to measure blood flow to the heart require the injection of radioactive chemicals or contrast agents that change the MRI signal and detect the presence of disease.

There are, however, small but finite associated risks with the existing procedure. This procedure also isn't recommended for a variety of patients such as those with poor kidney function.

MRI is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body.

"The method opens the door to a new era and totally novel way of doing cardiac stress testing to identify patients with ischemic heart disease" said Dr. Rohan Dharmakumar, project leader and an Associate Director of the Biomedical Imaging Research Institute at Cedars-Sinai.

"This approach overcomes the limitations of all the current diagnostics -- there would no longer be a need for injections or physical stress testing like running on treadmills,” Dharmakumar added.

The cfMRI method can also be used in other cases where heart blood flow is affected. This includes the effects of a heart attack or damage to the heart during cancer treatment. Due to its minimal risk, this new tool can safely be used with the same patient multiple times to better select the right treatment and find out early on if it is working.

Prato pointed out that "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."

The team included researchers from Lawson, Cedars-Sinai, the University of California, King's College in the United Kingdom, University Health Network and the University of Toronto, Siemens Healthineers and the University of Edinburgh in the UK.

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