Interventional MRI using multiple 3D angiography roadmaps with real-time imaging

Purpose: To enhance real-time magnetic resonance (MR)-guided catheter navigation by overlaying colorized multi-phase MR angiography (MRA) and cholangiopancreatography (MRCP) roadmaps in an anatomic context. Materials and Methods: Time-resolved MRA and respiratory-gated MRCP were acquired prior to real-time imaging in a pig model. MRA and MRCP data were loaded into a custom real-time MRI reconstruction and visualization workstation where they were displayed as maximum intensity projections (MIPs) in distinct colors. The MIPs were rendered in 3D together with real-time multislice imaging data using alpha blending. Interactive rotation allowed different views of the combined data. Results: Fused display of the previously acquired MIP angiography data with real-time imaging added anatomical context during endovascular interventions in swine. The use of multiple MIPs rendered in different colors facilitated differentiation of vascular structures, improving visual feedback during device navigation. Conclusion: Interventional real-time MRI may be enhanced by combining with previously acquired multi-phase angiograms. Rendered as 3D MIPs together with 2D slice data, this technique provided useful anatomical context that enhanced MRI-guided interventional applications.