Coming soon to the State’s public hospital system is cardiac magnetic resonance imaging (MRI), a noninvasive technique used to diagnose and evaluate conditions such as congenital heart defects, heart valve problems, coronary artery blockage and heart attacks, congestive heart failure, pericardial sac disease and cardiac tumors. This technology allows imaging of the heart without exposure to any radiation. “Basically, cardiac MR uses magnetic fields to excite certain atoms in the body,” explained Dr. Mark Stellingworth, invasive cardiologist and director of diagnostic catheterization at LSU’s University Medical Center in Lafayette. “When these atoms relax, they send out signals, and the signals can be measured by the device. An image can be composed from these signals. Cardiac MRI generates very high spatial and temporal resolution pictures of the heart and its surrounding structures.”

 

When Stellingworth started practicing as a cardiologist at UMC, he kept reading about cardiac MR developments in cardiovascular imaging journals. After nearly a year of research, he thought the facility’s 3 Tesla magnet would be ideal for implementing the technique. With the support of UMC, Stellingworth traveled to the University of Pennsylvania in Philadelphia in October for a three-month training program in cardiac MR.

 

During the first month, Stellingworth learned about the complicated world of cardiac MRI physics. Since then, he has spent every day from about 7 a.m. to 5 p.m. at both work stations and with the magnet to study the practical and technical affects of the device. He completed the program in late January. Upon his return to UMC, he underwent a week of intensive training with his technologists as well as GE’s magnet representatives. Dr. Stellingworth states this is also a collaborative effort between himself and the radiologists at UMC. “Our intention is to spend the month of February tweaking the protocols and getting them approved,” he said.

 

Once the cardiac MRI program is up and running, UMC will be the go-to place for patients with certain heart conditions such as congenital heart disease and cardiomyopathies. “There are some private hospitals that have it, but UMC will probably the first public hospital to be utilizing this technique on a regular basis in Louisiana,” Stellingworth projected. 

 

With its 3 Tesla magnet, UMC will get better image contrast with its scans than facilities using a 1.5 Tesla magnet. This means that technicians will get more detailed scans in a shorter amount of time. This technology is especially effective for monitoring congenital heart defects, cardiomyopathies and ejection fraction. “Cardiac MRI is the gold standard for the ejection fraction, or the heart squeeze,” he said. “We can get a better picture of the heart’s EF with cardiac MRI.”

 

In Louisiana, many people are born with heart defects. Back in the 1960s, a lot of these patients did not live past childhood. Since that time, researchers and physicians have been developing new techniques to correct these deformities and extend patients’ life-spans. As these patients get older, their corrective shunts and other surgical procedures must be closely monitored. The problem was capturing clear images of a beating heart with existing techniques. But now, in the 21^st century, MR technology has evolved which allows physicians to take high resolution pictures of not only the structures of the heart, but its overall function.

 

Cardiac MRI is also beneficial for finding viable heart tissue. “If a patient has had a heart attack, and you are trying to evaluate whether or not his heart would respond if you put a stent in, you can use cardiac MR to detect tissue that is still living from tissue that is perceived to be scar,” Stellingworth explained. “So, we can distinguish between those two things with cardiac MR, probably to a greater degree than we’ve ever been able to do with any other imaging. It is at least comparable, or perhaps superior, to other imaging modalities, such as nuclear imaging, to test for viable tissue of the heart.”

 

The advantage to using cardiac MRI compared to nuclear testing is that MRI uses no radiation.
“One of the things that is being debated now in the medical literature is how much radiation are we giving our patients and whether that’s going to have negative effects long-term,” Stellingworth noted. “You obviate the need for that debate by using cardiac MR in certain circumstances where appropriate.”

 

This technique does have its limitations. As with other MRI scans, cardiac MR cannot be used in patients who have brain clips, pacemakers, defibrillators, or any other metal in their bodies. Other contraindications are for patients with kidney disease.

 

In the future, Stellingworth plans to implement cardiac MR stress testing. For now, he is trying to develop protocols for congenital heart disease, ventricular function and cardiomyopathies. He is also hoping to use the procedure for tissue viability.

 

One potential application is for cardiac screening of cancer patients prior to undergoing chemotherapy. Currently, the gold standard is a MUGA (multiple gated acquisition) scan, which assesses the heart’s function using a radioactive substance, Technetium 99. “We can do the exact same thing with cardiac MR, but patients don’t get any radiation,” Stellingworth explained. “So, it’s my belief that cardiac MR has an excellent opportunity, particular for patients prior to chemotherapy to allow them to get a baseline ventricular function study without any radiation, and then we can continue to monitor them long-term. I think that if physicians are worried about exposing their patients to too much radiation, this provides a viable alternative to MUGA scans. It may not necessarily replace them, but I think that if your patient has any worries about radiation therapy, we could possibly minimize the adverse effects of one additional radiation exposure.”

 

Stellingworth hopes to have a running cardiac MRI program by March. “My first year on the device, or perhaps longer, will be trying to understand the technical aspects so that we can provide a good comprehensive study,” he said. “People from all over the state will be able to come to UMC – both paying and non-paying patients. We believe this technology will be a great benefit to all the citizens of the state of Louisiana.”