Imaging “hidden” regions of the heart

After suffering a heart attack, some patients develop a microvascular obstruction, an area of the injured heart with extremely poor blood flow. These patients are at an increased risk of developing heart failure in the future.

Medical imaging technologies such as magnetic resonance imaging (MRI) and positron emission tomography (PET) can be used to study the remodeling process after a heart attack that can lead to a microvascular obstruction. However, poor blood flow makes it difficult to get contrast agents into the obstruction. Contrast agents are used in medical imaging to show contrast between different types of tissue, such as damaged and healthy tissue.

Benjamin Wilk, a PhD candidate at Lawson Health Research Institute and Western University’s Schulich School of Medicine & Dentistry, will investigate whether a hybrid PET/MRI system and a new method of administering contrast agents can allow researchers to image microvascular obstructions and study these “hidden” regions in the heart.

Contrast agents are usually injected as a bolus, meaning the entire injection is administered immediately. In this study, participants will instead receive a constant infusion of an MRI contrast agent and PET tracer, which means the injection will be delivered over the course of an hour. The MRI contrast agent they are using is sensitive to blood flow and scar tissue, and the PET tracer is sensitive to inflammatory cells.

This will allow researchers to study the anatomy, blood flow and inflammatory processes in microvascular obstructions a week after heart attack. Participants will then be imaged again after six weeks to study the long-term effects on heart function.

“Studying the heart after a heart attack using novel contrast agent injection strategies with simultaneous PET/MRI could provide crucial information for treatment planning, helping us reduce the number of people affected by heart failure in the future,” says Wilk. “This project could also lead to further research into finding better ways to administer PET tracers and MRI contrast agents. These methods could be applied to different diseases as well.”

Wilk received a Lawson Internal Research Fund (IRF) Studentship to conduct the study, which will be supervised by Dr. Frank Prato, Assistant Director, Lawson and leader of the Lawson Imaging research program at St. Joseph’s Health Care London.

“Lawson's IRF is valuable for students for many reasons. It not only allows us to conduct further research, it also enriches our experience by giving us opportunities to write grants and attend conferences,” adds Wilk.

The IRF is designed to provide Lawson scientists the opportunity to obtain start-up funds for new projects with the potential to obtain larger funding, be published in a high-impact journal, or provide a clinical benefit to patients. Funding is provided by the clinical departments of London Health Sciences Centre and St. Joseph’s Health Care London, as well as the hospital foundations (London Health Sciences Foundation and St. Joseph’s Health Care Foundation).