August 29th, 2012

Pilot Study Demonstrates Feasibility of MRI-Guided Catheterization

A small pilot study has demonstrated that it may one day be possible to replace x-rays with MRI to guide some cardiac catheterization procedures.

As reported in the European Heart Journal, researchers at the National Heart, Lung, and Blood institute (NHLBI) performed x-ray and MRI-guided transfemoral right heart catheterization in 16 patients (4 with shunt, 9 with coronary artery disease, 3 with other indications). Each patient first underwent catheterization under x-ray guidance, which was then repeated twice with MRI, once using an air-filled balloon-tipped catheter and once using a gadolinium-filled balloon-tipped catheter.

In all but one patient, complete guidewire-free catheterization was successful with both techniques. The researchers said that MRI using gadolinium-filled balloons was “at least as successful as x-ray in all procedure steps, more successful than MRI using air-filled balloons, and better than both in entering the left pulmonary artery.” Procedure time was not significantly longer with MRI. “Catheter conspicuity was best under x-ray and next-best using gadolinium-filled MRI balloons,” the researchers reported.

“This could be the first chapter of a big story,” said Robert S. Balaban, scientific director of the NHLBI’s Division of Intramural Research, in an NHLBI press release. “It provides evidence that clinical heart catheter procedures are possible without using radiation, which could be especially valuable in areas such as pediatrics.”

The authors acknowledge an important limitation of their research: “We do not believe coronary artery interventional procedures are a realistic possibility because of inadequate spatial and temporal resolution. However, we do believe structural heart interventions to be realistic therapeutic targets, including delivery and repair of cardiac valve devices, non-surgical access and closure of large transthoracic cardiac access ports, repair of other cardiac structural defects, and enhanced image guidance of peripheral artery interventions such as recanalization of chronic occlusion.”

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