MRI cardiac catheterization poised for success in children with congenital heart disease

08/12/05

Technique vividly depicts heart anatomy in three dimensions

(BETHESDA, MD)--Technological advances that combine the stunning image quality of magnetic resonance imaging (MRI) with the efficient elegance of catheter interventions are reshaping the treatment of children with congenital heart disease. According to a report in the September 2005 issue of Catheterization and Cardiovascular Interventions: Journal of the Society for Cardiovascular Angiography and Interventions, faster scan times, more detailed images, more powerful magnets, and open scanners that offer physicians access to patients during interventional procedures are all making real-time, MRI-guided cardiac catheterization a reality.

"MRI is on the verge of changing the way both diagnostic and interventional catheterization is done in children with congenital heart disease," said Dr. Phillip Moore, a professor of clinical pediatrics and director of the Congenital Cardiac Catheterization Laboratory at the University of California, San Francisco. "It's starting to reach its stride and, in our hospital, is already replacing some diagnostic catheterization procedures."

MRI cardiac catheterization is capturing the attention of interventional cardiologists because it can do what conventional x-ray angiography cannot. While x-ray angiography depicts the inside of the blood vessels and heart chambers in two dimensions, and the rest of the heart as a mass of gray, MRI provides a detailed three-dimensional picture of the heart. This enables the interventional cardiologist to see blood vessels inside and out, to accurately measure the size and volume of heart chambers and the thickness of the heart muscle, and to visualize the heart valves and other structures in relation to one another, and from any angle.

"MRI allows us to get a much better three-dimensional image--almost the image that a surgeon gets when looking directly at the heart," Dr. Moore said. "That's information you can only guess at with angiography."

Today, it is possible for MRI not only to image the heart in great detail but to do so while the heart is beating and display those images in real time. This enables the interventional cardiologist to track a special MRI-compatible catheter as it wends it way through the heart and to make fine adjustments when implanting therapeutic devices, such as stents.

Much of the research into MRI cardiac catheterization has taken place in animals, but it is now extending its reach to humans. Dr. Moore and others have combined MRI and conventional angiography in diagnosing congenital heart disease in children. He expects to soon begin using MRI cardiac catheterization in treatment procedures, placing stents to prop open constrictions in the pulmonary artery and aorta.

For all its promise, MRI cardiac catheterization will reach its full potential only when researchers and commercial manufacturers develop a more complete array of catheters and devices that can be used in an MRI scanner. Further advancements in scanner design will also enable imaging of even smaller structures, including the tiniest of coronary arteries, Dr. Moore said. "There is a lot we still need to achieve, but clearly MRI cardiac catheterization is going to be quite important," he said.

Source: Eurekalert & others

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