Imaging the Heart: The New Frontier
Chest pains, heart flutters, heart attack -- they are the signposts of heart
troubles. In the past, such symptoms might mean a treadmill stress test or a
cardiac catheterization to diagnose the problem.
That's changing with the advent of new imaging technology: CT scans, MRI,
3-dimensional echocardiography (3-D echo), and PET/CT.
"It's a new era we're at the tipping point right now," says Robert
M. Steiner, MD, FACC, director of cardiac and pulmonary imaging at Temple
University Health System in Philadelphia.
The traditional stress test shows the heart's function and how it performs
under exertion such as walking on a treadmill or pedaling a stationary bike. In
cardiac catheterization (cardiac cath), the cardiologist can examine the
valves, arteries, and chambers via the use of contrast dye and a catheter
inserted into the groin or arm.
But with the new imaging technology, "we can now get much the same
information as we could with the [older] tests -- and do it much less
invasively," Steiner tells WebMD.
"All these new tests examine function and anatomy beautifully. They are
easier to perform, and often less expensive," Steiner says. "And
because they are less invasive, they are easier on the patient."
Computed Tomography Angiography (CTA)
As a diagnostic tool for early heart disease, CTA is a major advance.
"CTA is a better technique for finding small blockages in coronary
arteries," says Mario Garcia, MD, director of cardiovascular imaging at the
Cleveland Clinic Foundation. "If you have a blockage in the arteries, CTA
is the best way to find it."
The CT scanner -- which looks like a large donut -- is an X-ray machine. A
contrast dye is injected into the patient's arm and, as the patient lies on a
table, the CT scanner rotates taking multiple images -- yielding highly
detailed images of blood vessels and the heart.
Just a few years ago, the diagnosis would have involved a cardiac cath
procedure, which can take an hour or more, compared to the CT scanner's five
Cardiac cath is still the better test for determining treatment for patients
with serious heart disease, says Glenn N. Levine, MD, a cardiology professor at
Baylor College of Medicine and director of the Houston VA's Cardiac
"But with CTA, we can rule in or rule out significant heart disease and
artery disease, or congenital abnormalities -- and we can see it in just a few
minutes," Levine tells WebMD. "With CTA, we can view the structures of
the heart and coronary arteries in any dimension, including a three-dimensional
view. It's a very good test." For patients, there's much less anxiety
compared to a cardiac cath, says Steiner. "There is minimal risk with CTA.
And the results are over 95% accurate."