MR fluoroscopy in vascular and cardiac interventions (review)

Abstract

Vascular and cardiac disease remains a leading cause of morbidity and mortality in developed and emerging countries. Vascular and cardiac interventions require extensive fluoroscopic guidance to navigate endovascular catheters. X-ray fluoroscopy is considered the current modality for real time imaging. It provides excellent spatial and temporal resolution, but is limited by exposure of patients and staff to ionizing radiation, poor soft tissue characterization and lack of quantitative physiologic information. MR fluoroscopy has been introduced with substantial progress during the last decade. Clinical and experimental studies performed under MR fluoroscopy have indicated the suitability of this modality for: delivery of ASD closure, aortic valves, and endovascular stents (aortic, carotid, iliac, renal arteries, inferior vena cava). It aids in performing ablation, creation of hepatic shunts and local delivery of therapies. Development of more MR compatible equipment and devices will widen the applications of MR-guided procedures. At post-intervention, MR imaging aids in assessing the efficacy of therapies, success of interventions. It also provides information on vascular flow and cardiac morphology, function, perfusion and viability. MR fluoroscopy has the potential to form the basis for minimally invasive image–guided surgeries that offer improved patient management and cost effectiveness.

Magnetic Particle Imaging: Visualization of Instruments for Cardiovascular Intervention

“…This is a first step toward cardiovascular interventions by using MPI. Compared with other cross-sectional imaging modalities for interventional procedures, the gained temporal resolution (46 volumes per second) with MPI is considerably higher than that with interventional MR imaging (about 5 frames per second [12,13]) and Carm cone beam CT (image acquisition time of about 5 seconds [14]). The high temporal resolution combined with three-dimensional imaging inherent to MPI allows delineation of moving instruments independent of the course of the vessel.…”

“…The spatial resolution of an MPI system does not correspond exactly to the voxel size (9,12) but is determined by the selection field gradient and the steepness of the particle magnetization curve (13). For our images, …”

MR Imaging–guided Electrophysiological Ablation Studies in Humans with Passive Catheter Tracking: Initial Results

“…Over the past two decades, magnetic resonance (MR) imaging has emerged as a valuable tool in cardiac imaging, and other publications have demonstrated the potential and development of MR imaging-guided endovascular interventions (5)(6)(7). MR imaging is free of ionizing radiation and provides high-contrast images with any Implication for Patient Care n In this early phase, several limitations have to be overcome before MR imaging-guided EP ablation studies can be used in clinical routine; however, this method might have clinical potential because of the elimination of ionizing radiation and the additive benefit of tissue characterization.…”

Usefulness of cardiac MRI in the prognosis and follow-up of ischemic heart disease

“…Due to its lower resolution, it is only possible to make a qualitative assessment of contractility, not a quantitative one. 18 The volumetric and functional analysis of the heart are performed by acquiring contiguous images (between 8 and 12) usually on a short axis. Through the outlining of the endocardium borders in diastole and systole and those of the epicardium in diastole we can obtain function parameters such as the telediastolic and telesystolic volumes, the ejection fraction, the stroke volume, the cardiac output of both ventricles and the left ventricle myocardial mass.…”