MRI Proves Effective Guiding Heart Catheter Procedures

Heart catheter procedures guided by magnetic resonance imaging (MRI) are as safe as X-ray-guided procedures and do not take any longer, according to a pilot study. The findings indicate that real-time MRI-guided catheterization could be a radiation-free option to specific X-ray-guided procedures.

A report of the study, which was conducted by researchers within the intramural program of the US National Institutes of Health’s (NIH; Bethesda, MD, USA) National Heart, Lung, and Blood Institute (NHLBI), is available online October 2012 in the European Heart Journal. “This could be the first chapter of a big story,” said Robert S. Balaban, PhD, scientific director of the NHLBI’s Division of Intramural Research. “It provides evidence that clinical heart catheter procedures are possible without using radiation, which could be especially valuable in areas such as pediatrics.”

Typically, X-ray fluoroscopy pictures have higher resolution but less detail than MR images. The investigators performed transfemoral catheterization (which involves threading a catheter from the large vein in the leg to the heart) in 16 patients to evaluate the right side of the heart, including the attached veins and the pulmonary arteries. The study participants all required catheterization for heart and valve disease. The researchers conducted the procedure in the 16 patients using X-ray guidance, and then repeated it two times using real-time MRI guidance of a balloon-tipped catheter filled with air or with a contrast agent.

The X-ray and MR catheterizations were effective in 15 of the 16 participants. One patient had required the use of a wire to help guide the catheter under X-ray, and at present no guidewires are available that work under an MRI. The median procedure time for the two approaches was comparable-- approximately 20 minutes. The investigators anticipated the MRI-guided procedure to take much longer because an MRI-compatible catheter can be harder to see in an MRI-generated image than a traditional steel catheter can be in an X-ray-generated image.

“Developing safe and conspicuous catheter devices for MRI is the chief obstacle to overcome before this approach can be widely applied at hospitals,” said study lead Robert J. Lederman, MD, a senior investigator in the NHLBI’s Cardiovascular and Pulmonary Branch. “But with improved tools and further improvement of the procedure, real-time MRI catheterization may become a realistic option for many people.”

Dr. Lederman’s research group is still performing MRI catheterization on further patients, and is currently designing improved catheters and other application that will be more observable under MRI to help advance the technology. The NHLBI investigators also hope to utilize MRI to guide nonsurgical catheter treatments in the future, in addition to guiding catheter procedures.

NHLBI plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers US health education campaigns on healthy weight for children, women and heart disease, and other topics.

Related Links:
US National Heart, Lung, and Blood Institute