From pre-operative cardiac modeling to intra-operative virtual environments for surgical guidance: an in vivo study

As part of an ongoing theme in our laboratory on reducing morbidity during minimally-invasive intracardiacprocedures, we developed a computer-assisted interventi on system that provides safe access inside the beatingheart and sucient visualization to deliver therapy to intracardiac targets while maintaining the ecacy of theprocedure. Integrating pre-operative information, 2D trans-esophageal ultrasound for real-time intra-operativeimaging, and surgical tool tracking using the NDI Aurora TM magnetic tracking system in an augmented virtualenvironment, our system allows the surgeons to navigate instruments inside the heart in spite of the lack ofdirect target visualization. This work focuses on further enhancing intracardiac visualization and navigation bysupplying the surgeons with detailed 3D dynamic cardiac models constructed from high-resolution pre-operativeMR data and overlaid onto the intra-operative imaging environment. Here we report our experience during an invivo porcine study. A feature-based registration technique previously explored and validated in our laboratorywas employed for the pre-operative to intra-operative mapping. This registration method is suitable for invivo interventional applications as it involves the selection of easily identi“able landmarks, while ensuring a goodalignment of the pre-operative and intra-operative surgical targets. The resulting augmented reality environmentfuses the pre-operative cardiac model with the intra-operative real-time US images with approximately 5 mmaccuracy for structures located in the vicinity of the valvular region. Therefore, we strongly believe that ouraugmented virtual environment signi“cantly enhances intracardiac navigation of surgical instruments, while on-target detailed manipulations are performed under real-time US guidance.Keywords: Image-Guided Cardiac Procedures, Pre-operative Modeling, Intra-operative Imaging, AugmentedVirtual Reality, Data Integration for the Clinic/OR.