New MRI method predicts heart disease risk based on heart fat content

Everyone knows that excess fat around the waist and thighs is bad for your health, but UVA Health scientists are working on a non-invasive way to assess the health risks of unnoticeable fat around the heart.

Researchers led by Frederick H. Epstein, Ph.D., of the University of Virginia’s Department of Biomedical Engineering, are trying to use magnetic resonance imaging (MRI) to assess the composition of the fatty tissue that surrounds the heart. Analysing this tissue will allow doctors to identify patients at greatest risk of developing potentially fatal heart diseases such as coronary heart disease, atrial fibrillation (irregular heartbeat) and heart failure, and predict how well these patients may respond to treatment.

Early trials of the technique have provided encouraging signs that the approach could be a powerful tool to improve patient care.

‘Using the new MRI technique, for the first time we can recognise the composition of the fat that accumulates around the heart. This is very important because depending on the composition, the fat surrounding the heart can release harmful substances directly into the heart muscle, leading to serious heart problems,’ says researcher Amit R. Patel, a cardiologist and imaging expert at UVA Health and the University of Virginia School of Medicine.

Through our ongoing research, scientists have been able to prove that it is possible to convert the unhealthy fat that surrounds the heart into a healthier type of fat through dietary changes and exercise or through medication. In this way, the complications associated with heart disease can be reduced.

Our hearts are naturally surrounded by a layer of fat known as ‘epicardial adipose tissue’. In healthy people, this fat is protective and vital for heart function. But in some people, especially those who are obese and have risk factors for heart disease such as diabetes, high blood pressure, smoking and poor diet, this fat can accumulate excessively, become inflamed and undergo harmful changes in its composition.

UVA researchers use magnetic resonance imaging to assess the amount and composition of fat. The imaging technology essentially provides a look inside the body without the need for surgery. By analysing the content of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids – fats that are commonly found in our diet – in epicardial fat tissue, doctors will be able to identify patients who may have heart problems before symptoms appear. Identifying and correcting this problem could slow the progression of cardiovascular disease, which is the No. 1 cause of death both in the U.S. and worldwide.

Researchers at UVA had to overcome a number of serious challenges in creating the new tool. For example, the heart and nearby lungs are constantly in motion, which is a huge obstacle to getting clear images of fat tissue. But by developing innovative imaging approaches, scientists can now get the images they need in a single breath-hold.

The ability to make such measurements in epicardial adipose tissue has required the use of advanced computational techniques to isolate the unique structure of saturated fatty acids from the overall noisy signal.

The UVA team has already tested their technology both in the lab and on a limited number of patients. They found that the fat around the heart in obese patients who have had a heart attack consists of excessive amounts of saturated fatty acids. ‘This suggests that this new MRI technique could be a useful clinical tool for identifying at-risk patients and predicting their outcome,’ Patel says. – Being able to see the composition of the fat surrounding the heart will improve our understanding of heart disease and may lead to new treatment strategies in the future.’