May 30, 2003

Low-risk, non-invasive technology introduced for coronary imaging

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Dr. Mark Lawson is leading the new Magnetic Resonance Angiogram technology at Vanderbilt. According to Lawson, the MRA would be used much like ultrafast CT scanning for diagnosis, but without the risks of X-ray exposure or dye injection. (photo by Dana Johnson)

Low-risk, non-invasive technology introduced for coronary imaging

Coronary MRA of the right coronary artery.

Coronary MRA of the right coronary artery.

Vanderbilt University Medical Center is one step closer to changing the way doctors look at coronary arteries.

Traditionally, cardiologists use cardiac catheterization to visualize the coronary arteries and the workings of the heart. The procedure, which has small risks associated with it, calls for a catheter to be threaded to the heart by way of an arterial puncture. Dye is injected through the catheter to see the heart and the arteries that nourish it on X-ray images.

But that standard method is no longer the only way of viewing the heart. Vanderbilt cardiologists have been using Cardiac MRI (Magnetic Resonance Imaging) to provide an in-depth and non-invasive look at heart structure, function, and blood flow. In as little as 45 minutes, doctors are able to make a diagnosis that previously required multiple other tests to determine.

Now, physicians may no longer need invasive procedures to look at the coronary arteries of patients. Last week, Drs. Mark A. Lawson, assistant professor of Medicine and Radiology and Radiological Sciences, and David M. Kerins, associate professor of Medicine, joined by technical support staff, tested an updated software release that would allow doctors to view the coronary arteries, which nourish the heart muscle and can become blocked with plaque that may eventually lead to a heart attack.

The MRA (Magnetic Resonance Angiogram) took approximately 45 minutes to complete. Much of that time is spent locating the coronary arteries and designing a road map to acquire the MRA.

“We are the only ones in the state using this technology,” Lawson said. “There are several centers in the region with MRI programs, but none that we are aware of with this potential capability.

“This is the Holy Grail of MRI. Everyone is working toward this. Our vendor indicated that they would like for us to begin research applications for the use of MRA on patients. We are now working out the details. It is exciting to know that this is really possible and on the horizon.” Now, the plans at Vanderbilt are to rapidly implement clinical and research applications of the technology, according to Lawson.

The first coronary MRA at Vanderbilt was done on a volunteer, Dr. Douglas E. Vaughan, C. Sidney Burwell Professor of Medicine and chief of the division of Cardiovascular Medicine. Vaughan described the procedure as a major step forward in the establishment of a comprehensive cardiovascular MRI program at Vanderbilt. He said that the procedure itself is probably easily tolerated by most patients. It does require some short periods of breath holding (15-20 seconds at a time).

The ability to provide comprehensive exams at considerably less risk and cost to the patient is ideal. Lawson said the application would be used as a research tool only and could take a matter of weeks to develop the protocol.

“If a person presents with chest pain, it may be appropriate to use the MRA as an evaluation tool. Also for patients with multiple risk factors associated with cardiac disease, this may become an appropriate screening method,” Lawson said. “Ultimately, this is the method physicians would want to use if the MRA research proves beneficial.”

Lawson said the MRA would be used much like ultrafast CT scanning for diagnosis, but without the risks of X-ray exposure or dye injection.

MRI is a safe test. The patient is not exposed to radiation. Instead a magnetic field and radio waves are used to image the heart, which is not obscured from view by the lungs, breastbone or rib cage. Also, the heart can be viewed from any angle; something that Lawson said translates into great potential for this diagnostic application.