The picture of health

The picture of health

Imaging technology at the University of Ottawa Heart Institute shows cardiologists the best path to treating heart disease
May 1, 2007
Pictures may be worth a thousand words. But the pictures taken by the University of Ottawa Heart Institute’s cardiac positron emission tomography (PET) scanner are about one word only—life. The PET scanner measures the heart’s activity and produces a picture to detect and pinpoint heart ailments.
 

Researchers use the PET scanner to increase scientific understanding of heart disease, and cardiologists use PET images to take away some of the guesswork when deciding on treatment options. “We may even be able to determine if a patient will be more receptive to drug A or drug B,” says Rob Beanlands, Chief of Cardiac Imaging and Director of the National Cardiac PET Centre at the Heart Institute.

The PET Centre is the only one in Canada dedicated to cardiac imaging. A new mini-scanner, sensitive enough to use on laboratory mice, was recently installed. These capabilities, combined with the institute’s first-rate reputation, attract researchers from around the world.

Keiichiro Yoshinaga, an award-winning cardiologist from Japan, is just such a researcher. He recently completed a three-year clinical research fellowship at the Heart Institute. He was part of a rotating group of cardiologists from around the world who train there. Yoshinaga investigated links between treatments for sleep apnea, an obstructive sleep disorder sometimes called the snoring disorder, and heart disease.

“I was interested in doing research in Munich, Los Angeles, or London, but my supervisor knew about Dr. Beanlands’ work, and I was excited to work with one of the world’s top PET specialists,” says Yoshinaga. He was part of a Heart Institute research team examining how continuous positive airway pressure, a major treatment for sleep apnea, affects the heart. In this treatment, respiratory devices gently blow air through a mask with enough pressure to keep the throat open. PET scans show these devices may lead to benefits for heart health in sleep apnea patients.

During a PET scan, the patient spends between 10 minutes to an hour on a bed that moves through a doughnut-shaped scanner. It’s a painless procedure that relies on nuclear imaging. A tiny amount of radioactive substance called a tracer is injected into the patient and tracked by special cameras. The resulting PET scan shows the heart at work, and lets the cardiologist see which parts of the heart tissue are healthy and which have limited function or no function at all. Unlike an X-ray or CAT scan, which shows only structural details such as bone and cartilage, a PET scan provides images of the heart’s metabolic processes, such as oxygen consumption. Watch a video of a PET scan.

PET imaging can be done on an out-patient basis: the patient can be assessed and a test performed within 90 minutes. Cardiac PET is also non-invasive, which means patients don’t have to undergo surgery or be tested using a cardiac catheter. The low-risk nature of the PET scan contributes to its reputation as an ideal tool for combining research and clinical care.

“We can take what we’ve learned in the lab, apply it to patients and always remain on the frontier of what is new and what helps make people better,” says Beanlands. And with heart disease and stroke being responsible for one in three deaths in Canada, remaining on the frontier of cardiac care will help save many lives.

Benefits

The University of Ottawa Heart Institute’s PET scanner is helping to make sure the best treatments for heart disease are given to the right patients at the right time. The results are better health for Canadians and more efficient use of tight health-care budgets.

Delivering the right cardiac care is crucial. Treatment options can range from simple techniques like changing a person’s diet or prescribing drugs to invasive procedures such as a coronary artery bypass graft, angioplasty, or even a heart transplant.

There are a growing number of PET centres in Canada. Centres in Vancouver, Montreal, and Toronto use PET primarily for neurological evaluation, while others focus on cancer imaging. But the National Cardiac PET Centre at the University of Ottawa Heart Institute is the only facility devoted entirely to cardiovascular disease. The results of research at the Heart Institute are expected to expand this use of PET imaging to other centres for the benefit of all Canadians.

All Heart Institute patients undergoing PET imaging are asked to participate in a cardiac PET registry and are screened for possible participation in other clinical research studies using PET imaging. For example, in a three-year study of blood flow, which tracked 367 patients, researchers found that patients showing a normal PET scan were at low risk for heart problems such as heart attack, while people with abnormal scans were at high risk for these problems. The results, which are still being studied, showed that PET may be particularly useful for people suffering from obesity or people whose previous test results produced an uncertain conclusion. Through the registry and screening process, researchers find suitable research subjects for studies that “focus on helping to better direct resources to improve patient care,” says Beanlands.

Partners

Over the past few years, the University of Ottawa Heart Institute has collaborated with TRIUMF, a world-class subatomic physics research laboratory at the University of British Columbia, and MDS Nordion, a health and life sciences company in Ottawa. This partnership, which is only one of many, is focused on producing rubidium for the PET scanner. Rubidium offers a number of advantages over the current radioactive tracers used in the PET scanner. These tracers require an expensive cyclotron facility to produce radioactive material. Because producing rubidium does not require a cyclotron to be on site with the PET camera, it could help make PET scans more widely available.