Advanced heart imaging at the U allows for more accurate diagnosis
If you’ve ever had cause to see a cardiologist, your visit likely included echocardiography, or “echo.” This test, which uses sound waves to show how well the heart is pumping blood, forms the core of traditional heart imaging, along with X-ray and nuclear imaging.
But these methods may not always provide enough information for physicians to understand the cause of a patient’s symptoms or plan the best treatment.
Say you experience chest pains. Your doctor sends you for a stress test to gather information about how well your heart works during physical activity. The test doesn’t show a problem. But while traditional stress tests are good at revealing areas of decreased blood flow to the heart or past major heart attacks, they’re poor at showing whether a small heart attack might have happened.
Magnetic resonance imaging (MRI), however, can show extremely small amounts of scar tissue or dead cells in the heart, making it possible for doctors to detect even a tiny heart attack and pinpoint the exact site and extent of the damage.
“If I stopped at the traditional stress test, I might say, ‘Everything is normal, and there is nothing to worry about,’” says Uma Valeti, M.D., who directs the University of Minnesota’s cardiovascular imaging program. “That’s totally different from me telling you, ‘You didn’t have a major heart attack, but you did have a tiny one. That tells me there is a blockage building up in your heart vessels, so we’ve got to be very aggressive with modifying your risk factors to prevent future heart attacks.’”
Valeti says the complex cases he and his colleagues see require access to leading-edge technologies. University of Minnesota Medical Center, Fairview and all University of Minnesota Physicians Heart locations provide that access.
The new frontier in advanced imaging includes cardiac MRI, CT (computed tomography), and PET (positron emission tomography). Valeti says these technologies open up a new level of information for every area of cardiovascular medicine.
While advanced imaging is helping to reduce the impact of heart disease on people’s lives, it also has potential to reduce health care costs by cutting down on invasive procedures and repeated testing.
Cardiac CT, for instance, offers a lightning-fast, noninvasive alternative to angiography, which requires inserting a catheter and dye into the body. “With a CT angiogram, you get a lot more information than what you get with a traditional angiogram,” says Valeti. “And all of this at a lower risk of complications and in many cases at a lower dose of X-ray exposure.”
CT can show not only a blood vessel but also the walls of the vessel, including plaque that’s building up in those walls before it causes severe blockage, as well as the heart’s four chambers and valves. It also shows the sac around the heart and adjacent lung tissue, which do not show up on a traditional angiogram but may be responsible for a patient’s symptoms, Valeti says.
The newest tool available through the University is an ammonia PET scanner. Like nuclear imaging, PET quantifies the amount of blood flowing to the heart, but it does so with far less radiation and produces a much higherquality image, Valeti says. PET can detect inflammation in the heart, check blood flow to a transplanted heart, and evaluate the results of cardiac regenerative therapies such as stem cell treatments and gene therapy.
“The University of Minnesota is one of only a handful of centers in the country that can offer all of these imaging modalities to patients,” says Valeti. “Our goal is to make this one of the top 10 imaging programs in the country in the next five years.”
Most important, he says, is that University physicians will be able to provide these advanced techniques to help “the right patient at the right time with the right technology.”