Image Guided MRI

Working toward making cardiac care safer and less invasive for patients around the world, Rady Children’s has established the Dickinson Family Image-Guided Intervention Center under the direction of Kanishka Ratnayaka, MD. Experts at Rady Children’s already have started ground-breaking work performing the world’s first-in-human non-surgical connection of two large blood vessels in a patient with congenital heart disease.

Thanks to The Donald C. & Elizabeth M. Dickinson Foundation’s $2 million lead gift, this center will be the nation’s first pediatric image-guided intervention center of excellence, utilizing non-invasive radiation-free magnetic resonance imaging to diagnose and treat heart disease. This technology more safely and efficiently reduces risk, improves interventions and effectively transforms cardiovascular care in pediatric patients. Real-time cardiac MRI also addresses the two main limitations of conventional imaging and image guidance by providing better visualization of 3-D structural relationships and minimizing radiation exposure.

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The Radiation Free Solution

By Josh Baxt

This story originally appeared in Healthy Kids magazine

Interventional cardiac catheterization is one of the underappreciated heroes of modern medicine. Guided by X-ray images, cardiologists take a catheter and snake it up through a blood vessel toward the heart, opening up narrowed vessels and enabling them to replace a valve, stitch up a hole in the heart or repair a variety of other issues.

Catheterization has become a cardiovascular workhorse, particularly for children with congenital heart defects. The alternative would be open-heart surgery, which is quite effective but also adds a number of risks, as the ribs must be separated for surgeons to access the heart. Catheterization is minimally invasive and a particularly good option for sick children. At Rady Children’s Hospital-San Diego, nearly 100 children per year undergo a catheterization procedure to treat an abnormality that would have required cardiac surgery as recently as five years ago. But there’s a challenge.

To navigate the catheter through the body, cardiologists must rely on fluoroscopy, which is like an x-ray movie. The images aren’t great, and patients get small doses of radiation during each procedure, which can potentially have long-term consequences.

“Kids have growing and developing tissues, so they are particularly radiosensitive,” says Kanishka Ratnayaka, MD, an interventional pediatric cardiologist at Rady Children’s. Dr. Ratnayaka, who recently came to the Hospital from Children’s National Health System in Washington, DC, has spent many years working on an alternative to fluoroscopy: real-time cardiac MRI. This emerging technology produces no radiation, provides clearer pictures and could revolutionize how catheterization procedures are performed.

From Georgia to San Diego

Dr. Ratnayaka grew up in Athens, Ga. and thought he would return home and be a small-town pediatrician. But during his pediatric residency at Children’s National, he discovered how much he enjoyed pediatric interventional cardiology.

“I liked caring for children and was really fascinated by the way the heart works,” he says. “Plus, there was a lot of room for growth in the field.”

He found his niche caring for kids at Children’s National and conducting interventional cardiac MRI research at the National Institutes of Health (NIH), just up the road in Bethesda, Md. In the joint NIH/Children’s National program, physicians were determined to bring real-time, cutting-edge cardiac MRI to kids. In April 2013 they succeeded, as Dr. Ratnayaka and his colleagues opened one of the world’s first interventional cardiac MRI suites at Children’s National.

He was an emerging star in cardiology, and the leadership at Rady Children’s took notice, making it their priority to bring Dr. Ratnayaka to San Diego. They wanted him to replicate his Washington success and build upon it in San Diego by establishing an interventional cardiac MRI center at Rady Children’s. It was a great opportunity for everyone.

“One of the reasons I wanted to come to Rady Children’s is because the Hospital has a top-notch group of clinicians,” says Dr. Ratnayaka, “not only in providing care for patients, but also in thinking about the future of the field.”

San Diego had a number of other advantages. Dr. Ratnayaka was impressed by the wealth of biomedical research talent in the region. He notes that UC San Diego is the no. 2 biomedical engineering school in the country, and he’d already collaborated with researchers there. “I saw an opportunity to build something special,” he says.

Benefits of Interventional Cardiac MRI

If eliminating radiation from catheterization procedures were the only advantage of interventional cardiac MRI over fluoroscopy, that would be enough incentive to build the Image-Guided Intervention Center at Rady Children’s.

Performing one procedure might not be a big deal, but sometimes cardiologists have to go in several times to repair a more complex congenital defect or ensure the body is not rejecting a transplanted heart.

“This is a big deal with kids,” says John Moore, MD, MPH, division chief of cardiology and chief of the Department of Pediatric Cardiology at UC San Diego. “Many patients need multiple interventions. All that radiation places them at higher risk for cancer later in life.”

That advantage extends to the clinicians who work in the catheterization lab: cardiologists, anesthesiologists, nurses, technicians. They’re in there every day, often for more than one session.

But beyond safety, cardiac MRIs have another important distinction: The images are much clearer and can be rendered in three dimensions, giving clinicians a better view of the patient’s anatomy.

“You’ve seen an X-ray,” says Dr. Ratnayaka, “they’re gray and black and white. Imagine making your way through the woods in a fog. With MRI, you can see everything. You can see the beating heart, the lungs, all the vessels. You can see the blood flowing.”

This superior ability to image anatomical structures can help cardiologists better recognize where they are inside the body, adding that extra margin of safety. Equally important, it may give them opportunities to reduce how much surgical intervention is required.

“In surgery, you often take two blood vessels that are far apart and join them together,” says Dr. Ratnayaka. “If we could see those two blood vessels with MRI, we might be able to use minimally invasive techniques and avoid surgery.”

Challenges

As is often the case, enormous leaps like real time cardiac MRI take a long time to roll out. Many of the tools that work with X-rays are incompatible with MRI.

“Most of the devices we use in the X-ray environment have components that are either metallic or ferromagnetic,” says Dr. Ratnayaka. “What that means is they have some strength to them, some backbone. That backbone can distort the MRI pictures, so you can’t see the beautiful pictures you’re used to. However, if you take out that metal backbone, you may be able to see the background imaging well, but you may not be able to see the devices.”

Dr. Ratnayaka has spent more than a decade optimizing procedures and developing new tools that support cardiac MRI. In some cases, he and his team were able to modify off-the-shelf devices to solve a problem. In others, new approaches had to be developed. MRI-safe metallic and polymer guidewires, for example, are currently undergoing clinical testing.

Building a Center

When he got to San Diego, Dr. Ratnayaka hit the ground running to set up the nation’s first Image-Guided Intervention Center for children, which will focus on children with cardiac disease, and help those with other conditions as well. The effort received a big boost from the The Donald C. & Elizabeth M. Dickinson Foundation, which made a $2 million gift.

“We are grateful to the Dickinson family for their generosity,” says Dr. Ratnayaka. “We think it’s going to take around $10-15 million to build the center, and now we are well on our way.”

It took about three years to build the interventional cardiac MRI center at Children’s National, and Dr. Ratnayaka thinks the schedule will be similar in San Diego. He has been tireless in his efforts, recruiting a scientist and other personnel and developing plans for the site itself. “We are already looking at architectural plans and places on campus where the center might be located,” he says. “We should have it up and running in the next couple of years.”

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Learn more about the first-in-human non-surgical connection of two large blood vessels.