Methods for MR Guided Interventions in Coronary Vessels

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DESCRIPTION (provided by applicant):Methods for MRI Guided Interventions in Coronary Vessels. MRI can provide the means to assess both vascular and soft tissue morphology and function. For this reason, it is possible to combine vascular interventional MR methods with MR diagnostic methods to provide a single-modality comprehensive test. This combined test would not only diagnose disease, but would also guide interventional procedures and assess the results of intervention. Such capabilities could facilitate new therapeutic approaches and may result in improved management of patients with vascular disease, including coronary artery disease. The objectives of this proposal are first, to develop and implement MRI techniques suitable for MR-guided coronary interventions, and second, to assess the feasibility of performing MR-guided interventions in the coronary arteries. The central principle of the proposed approach is the generation of vascular contrast enhancement by intracoronary infusion of MR contrast agent. The objectives of this proposal will be addressed by performing computer simulations, phantom studies and in vivo studies on instrumented canines. We will pursue four specific aims. (a) Develop and optimize MR techniques, that include pulse sequences and RF coils, for dynamic near-real time multislice imaging of the coronary arteries, based on contrast-enhanced vessel by intracoronary infusion of MR contrast agent, saturation of the underlying tissue and reduction of the field-of-view with outer volume suppression. (b) Establish low-dose MR contrast agent intracoronary infusion protocols, i.e. concentration, volume, and duration of infusion, suitable for multiple dynamic coronary MR-angiography sessions during the same procedure. (c) Develop passive visualization approaches to image and differentiate contrast agent-filled interventional catheters from contrast enhanced coronary vessels, for guiding intracoronary procedures with MRI. Dual lumen and dual-coaxial percutaneous transluminal coronary angioplasty (PTCA) balloon catheter assemblies will be investigated for that purpose. (d)Assess the feasibility of performing MR-guided balloon PTCA on a canine model of graded generated stenosis to assess the results of the intervention via contrast-enhanced first pass perfusion imaging of the myocardium distal to the stenosis.