Magnetic Resonance Imaging in Guidance and Assessement of Cardiovasular Interventions

X-ray fluoroscopy is routinely used in patients to guide vascular and cardiac interventions, because of the ability to perform real-time imaging and easy access to patients during interventions (Athanasoulis, 2001; Lakhan et al., 2009; Sousa et al., 2005). X-ray fluoroscopy, however, is limited for defining soft tissue and obtaining functional information. The poor contrast between pathologic and healthy surrounding tissue hinders X-ray fluoroscopy in defining targets (Peters, 2006), which subsequently leads to blind delivery of therapies to the targets (Saeed et al., 2006, 2008a). On the other hand, MRI uses low energy and no ionizing radiation. It does not require the injection of iodinated contrast, which has been associated with complications, including nephrotoxicity and anaphylaxis. Several studies also showed that exposure to ionizing radiation from X-ray procedures is associated with an increased risk of cancer (Berrington et al., 2004; Frush, 2004; Prasad et al., 2004). A study showed that high dose or repeated administration of gadolinium-based MR contrast media might be a concern, especially in patients with impaired renal function (Sadowski et al., 2007). This problem can be reduced by ensuring a glomerular filtration rate of > 30 ml/min/1.73 m2 and contrast agents with high molecular stability (Bongartz et al., 2008). The recently developed real-time MR sequences offer high temporal/spatial resolution images, safety, accuracy, flexibility and functionality. It also offers rapid recon-