Real-time interactive MRI for guiding cardiovascular surgical interventions

Real-time magnetic resonance imaging (rtMRI) is a compelling modality for guidance of surgical interventions. An effective toolkit for planning and guidance of surgery using rtMRI includes continuously updated images with excellent soft tissue contrast, devices that are visible in the images, interactively adjustable imaging parameters, simultaneous imaging and display of multiple intersecting oblique planes, and the ability to measure blood flow and perfusion. MRI has the benefit of not exposing the patient, physician, or staff to ionizing radiation from X-rays. This chapter describes the initial experience in the development of minimally invasive surgical implantation of an aortic valve in the beating heart, using continuously updated rtMRI. The potential benefits of this approach include reduction of patient trauma from open heart surgery using cardiopulmonary bypass, and the ability to implant a more robust device than can be delivered by catheter-based methods. Since the heart is a moving target, the surgeon is guided by continuously updated images, rather than those previously acquired as in stereotactic procedures.