What’s all the hype about cardiac CT?

As the fifth in a series of six lectures given by the University of Arizona's Sarver Heart Center and sponsored by Green Valley Recreation, Dr. Vincent Sorrell gave a lighthearted (no pun intended) lecture on the latest advances in cardiac imaging.

An associate professor of clinical medicine and radiology at the UA, in 2005, Sorrell won the World Congress of Echocardiography 'Jeopardy' Championship in Buenos Aires, Argentina.

The nature of a lecture on heart disease and various tests available to determine any heart damage is serious, however, Sorrell's nature is to disseminate such information interjected with humor.

“CT Scans allow intense views and fantastic pictures of all angles of the heart—as if a surgeon cut open a chest. It allows a cardiologist to 'dial in and dial out' to get information,” he said.

Sorrell spoke of “responsible imaging,” which he follows and advocates. It means physicians should only order those tests deemed necessary and avoid unnecessary testing. Health care costs are rising in part because of costly medical imaging, he said.

Giving a brief overview of the different levels of cardiac tests Sorrell said a treadmill stress test is a common and safe test often administered initially.

Echocardiography is the single most comprehensive tool while nuclear images look at blood flow through the heart. Nuclear images do not see arteries; it focuses on blood flow, and can predict the likelihood of a person having a heart attack.

An MRI provides valuable information using powerful magnetic field and produces valuable images. “It looks at muscles… tells why someone is having heart failure,” Sorrell told the audience.

Responding to a question about a person with a pacemaker having an MRI Sorrell said there could be some risk because the magnetic power of the MRI affects the pacemaker's battery. If the battery has recently been replaced risks are lowered.

Cardiac CT, which he labeled the “workhorse of cardiology” is an electron beam that predominantly looks at arteries to determine if there is evidence of hardening of the arteries due to plaque build up.

Sorrell explained that 80 percent of plaque is fibrous or soft and 20 percent of what he termed “plaque burden” is calcified. “The location and severity of calcified plaque is important… as we age, the risk of having a calcium score is greater.

“Current imaging doesn't predict heart attacks very well; it's good at reducing symptoms but not at reducing heart attacks,” he said, adding, “It's a fact; one day we'll predict heart attacks.”

In current state-of-the-art Cardiac CT scans one rotation of by the scanner will result in 64 “slices” or views. In the future it will result in 256 slices, greatly enhancing a cardiologist's ability to see just about everything.

Speaking optimistically about the future, in closing Sorrell said, “Imaging is vital to managing heart disease and may lead to reduction in heart attacks… the future is full of rainbows.”

Tips from Sarver Heart Center to prevent heart disease:

Take responsibility for your health and know your risks.

Don't smoke or expose yourself to second-hand smoke.

Maintain a healthy blood pressure and monitor cholesterol.

Limit the calories and make exercise a daily habit.

Reduce stress

Stay informed; science is constantly changing.

Ellen Sussman is a freelance writer for the Green Valley News.