Interventional cardiac magnetic resonance imaging

Abstract

t v a s B AGNETIC RESONANCE imaging (MRI) has become the preferred routine imaging odality for many diagnostic questions. It offers uperior soft-tissue contrast, true cross-sectional or -dimensional coverage in arbitrary orientation, nd there are no known side effects. In recent ears, progress in both hardware and software aused a considerable boost of cardiac MRI. A ultitude of techniques is now available not only or anatomic imaging but also for functional imging, such as visualization of myocardial motion,1 ssessment of myocardial perfusion,2 and determiation of blood flow values.3 In many sites, cardiac RI is now routinely used for the diagnosis of oth acquired and congenital heart disease. Howver, minimally invasive treatment of cardiovascuar diseases, such as balloon angioplasty or stent elivery, is still routinely performed under x-ray uidance, whereas MRI-guided interventional proedures are currently under development. Among the first minimally invasive intervenional procedures performed under MRI guidance ere brain biopsies.4 These procedures impose nly moderate requirements on imaging speed, nabling the use of lower-field open magnets, hich grant readily access to the patient and offer dvantageous low radiofrequency (RF) power. Bipsy needles are furthermore relatively stiff and hort, avoiding safety concerns caused by RF eating and facilitating easy localization eg, by eans of an optical localization system.5 Cardiovascular interventions, however, with ardiac motion, more complicated anatomy, and equirement for flexible devices such as catheters nd guidewires, require faster image update at