In vivo cardiovascular catheterization under real‐time MRI guidance

Abstract

Purpose: To test the hypothesis that cardiac and coronary catheterization can be successfully performed under realtime MR guidance using a conventional x-ray angiographic catheter. Materials and Methods:Cardiac and coronary catheterization was conducted on eight farm pigs using a real-time True FISP sequence. A pigtail catheter was used for both left-and right-heart catheterizations performed on all eight animals, while an Amplatz or Judkins catheter was used for the right coronary catheterization that was attempted on five animals. The intravascular devices were visualized by means of their native susceptibility artifacts. For right coronary artery catheterizations, 25% diluted gadolinium (Gd) contrast material was injected to confirm engagement of the right coronary artery.Results: Cardiac catheterization of both the right-and leftheart chambers was successfully performed in all eight pigs. In addition, right coronary catheterization was successfully completed in four of the five pigs in which it was attempted. The procedure time for cardiac catheterization was one minute, while the time range required for coronary catheterization was 32-91 minutes. Conclusion:This work demonstrates that MRI-guided cardiac catheterization using conventional X-ray angiographic catheters is feasible; however, coronary catheterization with this passive-tracking technique is limited. CARDIOVASCULAR DISEASE is the leading cause of death in western countries. According to the American Heart Association, more than 1.3 million cardiovascular catheterizations are performed annually in the United States for diagnostic purposes, while more than 2 million are performed for interventional therapeutic purposes (1). To date, x-ray fluoroscopy remains the gold standard for guiding cardiovascular interventions. However, traditional X-ray fluoroscopy is limited as an imaging modality for studying the anatomy, function, and perfusion of the heart. Furthermore, fluoroscopy cannot provide high-resolution or high-contrast imaging of the artery wall, which therefore precludes the study of atherosclerotic plaque composition and the monitoring of local treatment delivery. The ionized contrast agent required and the subsequent radiation exposure are additional disadvantages of X-ray fluoroscopy. Because it offers excellent tissue contrast and flow sensitivity, MRI is a powerful tool for visualizing vessel walls and characterizing atherosclerotic plaque (2,3). In addition to being a radiation-free imaging modality, MRI is superior to conventional X-rays for demonstrating not only the vessel lumen but also the vessel wall. With the development of rapid image-acquisition techniques, recent studies (5,6) have explored cardiovascular catheterization under MRI guidance. Cardiovascular intervention can be performed under MRI guidance using either active-or passive-tracking methods (6,7). With passive tracking, various strategies (e.g., filling the catheter with contrast medium (8,9)) are utilized to visualize the tip of the catheter. However, to date there ha...

Motion in Cardiovascular MR Imaging

“…Motion from the Cardiac Cycle Cardiac gating.-With the advent of rapid MR imaging techniques, it is now possible to acquire single-shot real-time images without ECG gating, as has been used in interventional MR applications (51)(52)(53), rapid assessment of LV function (54), and angiography and flow measurement (55)(56)(57)(58). Compromises are made, however; with most techniques, image data are acquired over a number of cardiac cycles with the requirement that the data acquisition be (66)(67)(68), derive an ECG-like signal from cardiac-induced periodic variations in a line of k-space repeatedly acquired without phase encoding.…”

Interventional cardiovascular magnetic resonance: still tantalizing

“…They combined invasive hemodynamic measurements with velocity-encoded MR [ 107 ]. Others have reported less complex procedures in animals [ 108 , 109 ].…”

Stem cell therapy: MRI guidance and monitoring

“…Transmyocardial delivery devices that have been developed for interventional MRI applications have fallen into two classes of devices: passive and active catheters (60–62). The simplest passive catheter system was comprised of an introducer sheath, a stainless steel needle, and a conventional polyethylene catheter, and the catheter was guided to the endocardial surface based on hypointensities created by the needle (63).…”