 For those patients undergoing cardiac catheterization, an 8French sheath will be introduced via a femoral artery approach. This size sheath allows us to visualize the distal aorta while performing the intra vascular ultrasound IVUS. For these patients, if a femoral venous sheath is also positioned for clinical purposes, then this access will also be utilized to introduce the MRI coil. This imaging approach will allow us to compare the feasibility of intravascular MRI imaging from: a the artery; b the vein; c a combination of both. 