Scientists: Derek Boughner, MD, PhD, FRCPC, James A. White, MD, FRCPC, Maria Drangova, PhD , Terry Peters, PhD, FCCPM & Ting-Yim Lee, PhD, FCCPM
Cardiovascular disease is the leading cause of death and disability both men and women worldwide. This research program is dedicated to advancing imaging techniques for the early detection of cardiovascular disease; the risk stratification of patients with established disease; the guidance of cardiovascular interventions to treat the disease, and the development of pre-clinical imaging tools to seed basic research development for novel therapies.
Early Detection of Cardiovascular Disease
The linings of blood vessels and heart valves are vulnerable to the deposition of fat and cholesterol. In the arteries this leads to blockage, while in the valves this causes “stenosis”. The cardiovascular imaging research team is evaluating the role of high-resolution MRI to detect disease at an early stage when cholesterol-reducing drugs may be able to halt or even reverse this process. They are also investigating the role of stress perfusion MRI and CT for the early detection of disease in patients with coronary artery disease and a genetic disease called hypertrophic cardiomyopathy.
Identification of High Risk Patients
Patients who have suffered heart attacks or who have genetic or inflammatory heart disease invariably have scarred heart muscle. This scarring is a barrier to improvement by medical therapy and promotes sudden cardiac death (SCD) due to arrhythmia. Scar imaging may allow for optimal delivery of specialized pacemakers designed to both improve heart function and shock the heart out of life threatening heart rhythms. This team is investigating MRI scar imaging to identify patients likely to suffer SCD.
Guidance of Cardiovascular Interventions
Newer surgical and catheter-based cardiovascular procedures face several significant challenges. The desired target must first be reached, but must also then respond to the treatment. The first challenge can be greatly assisted using 3D structural imaging. However, the latter is best addressed using scar imaging where scarred heart muscle is highly unlikely to respond. Our researchers have developed the ability to co-register pre-procedural 3D MR imaging of both the coronary arteries and myocardial scar. These images, as well as 3D CT images can then be co-registered to intra-operative ultrasound to guide the placement of instruments, catheters, and devices within the heart. They also are working on guiding the delivery of radiofrequency ablations of the heart for the treatment of heart arrhythmias, and on developing techniques to better visualize the heart during interventions.
Image-Guided, Beating-Heart Interventions
Currently, surgery to treat abnormal valves, atrial fibrillation, and holes in the heart are performed by placing the patient on a heart-lung bypass machine and stopping the heart. The cardiovascular imaging research team is developing new procedures for minimally invasive surgery on the beating heart that negate the requirement for heart-lung bypass. These techniques provide the surgeon with intra-cardiac “vision” by combining a virtual reality view of the inside of the heart acquired from pre-operative CT or MR images, together with information available from intra-operative ultrasound.
Preclinical Imaging Developments
Part of the research program involves the development of new imaging techniques that can be used to monitor cardiac function in animal (mouse) models of cardiac disease. For these projects, the team works with colleagues in basic biological science to develop imaging methods that will be suitable for investigating disease progression and regression in models of cardiac disease. Most of this work is performed within the Robarts Pre-clinical Imaging facility using state-of-the-art micro-CT and micro-ultrasound scanners.