Imaging the Heart: The New Frontier
An echo test involves ultrasound -- high-frequency sound waves -- to
evaluate the function of heart muscle and valves, the same technology used to
ensure a developing baby is healthy. In a cardiac echo test, a wand-like device
is used to transmit ultrasound waves against the chest, to produce moving
images of the heart.
Advances in echocardiography have improved this already excellent medium,
Garcia tells WebMD. "Echo is biologically very safe. It uses no contrast
medium, no radiation -- so it can be repeated often. And echo can evaluate the
function of the heart muscle and valves better than any modality."
Portable Echo: Laptop-sized echo machines are making the
technology more portable than ever before, Garcia tells WebMD. "If you're a
paramedic, you can take it in a helicopter or ambulance, and get much
information before the patient gets to the hospital. We cannot do that with
other devices. In fact, [we] can do echo in space with the astronauts."
Portable echo devices are being used in high school and college sports
programs, he says. "There is always a small percentage of student athletes
that experience sudden cardiac death, who are too young to have developed heart
disease," Garcia says. "We can screen athletes before they get into
competitive sports. It is very inexpensive."
Three-Dimensional Echo: With 3-D echo, the cardiologist
can obtain multiple ultrasound images of the heart's interior -- then assemble
them into a complete image of the heart in motion, Steiner explains. "It
allows us to view the heart anatomy in a different way -- to get all sorts of
special images we couldn't get before."
3-D echo provides more accurate measurements of heart muscle function and a
better view of heart valves than possible before, Garcia tells WebMD. "It
also provides automatic measurement of heart muscle function. Rather than
eyeball it, we can use computer analysis of how strong the heart muscle is
contracting -- how strong blood is pumping."
The procedure is used to evaluate complex valve or congenital heart disease,
he adds. "Because it is an emerging technology, we are still trying to
define its clinical applications."
Intracardiac Echo: Echo is being used during cardiac cath
procedures, Garcia says. "A small transducer is threaded through the
catheter," he tells WebMD. "It's a way of taking echo into the heart,
so we can use it as a guide during an interventional procedure - such as
closing holes in the heart, ablating arrhythmias, or ballooning open a narrow
valve. This ultrasound provides a more accurate image to monitor the procedure
while it is being performed."
MRI Heart Scans
Cardiac MRI "provides the gold standard of cardiac function and anatomy
unsurpassed image quality in evaluating heart structure and function in
3-D-quality moving images," Levine tells WebMD.
And cardiac MRI "shows us more than echocardiography or an exercise
stress test," Steiner adds. "Those tests have benefits, but MRI shows
more in terms of the heart's shape, size, volume, function. We can see if there
is valve disease, heart abnormalities, heart tumors, clots in the heart --
anything to do with anatomy and function. All the other tests can show parts of
that, but MRI potentially shows it all."