From pre-operative cardiac modeling to intra-operative virtual environments for surgical guidance: An in vivo study Cristian A. Linte a,b , Marcin Wierzbicki g , John Moore a , Chris Wedlake a , Andrew D. Wiles a,c , Daniel Bainbridge e,f , G´ erard M. Guiraudon a,f , Douglas L. Jones d,f and Terry M. Peters a,b,c,f a Imaging Research Laboratories, Robarts Research Institute - London ON Canada b Biomedical Engineering Graduate Program, Univ. of Western Ontario - London ON Canada c Department of Medical Biophysics, Univ. of Western Ontario - London ON Canada d Department of Physiology and Pharmacology, Univ. of Western Ontario - London ON Canada e Division of Anesthesia, Univ. of Western Ontario - London ON Canada f Canadian Surgical Technologies and Advanced Robotics - London ON Canada g Department of Physics, Grand River Regional Cancer Centre - Kitchener ON Canada ABSTRACT As part of an ongoing theme in our laboratory on reducing morbidity during minimally-invasive intracardiac procedures, we developed a computer-assisted intervention system that provides safe access inside the beating heart and sufficient visualization to deliver therapy to intracardiac targets while maintaining the efficacy of the procedure. Integrating pre-operative information, 2D trans-esophageal ultrasound for real-time intra-operative imaging, and surgical tool tracking using the NDI Aurora TM magnetic tracking system in an augmented virtual environment, our system allows the surgeons to navigate instruments inside the heart in spite of the lack of direct target visualization. This work focuses on further enhancing intracardiac visualization and navigation by supplying the surgeons with detailed 3D dynamic cardiac models constructed from high-resolution pre-operative MR data and overlaid onto the intra-operative imaging environment. Here we report our experience during an in vivo porcine study. A feature-based registration technique previously explored and validated in our laboratory was employed for the pre-operative to intra-operative mapping. This registration method is suitable for in vivo interventional applications as it involves the selection of easily identifiable landmarks, while ensuring a good alignment of the pre-operative and intra-operative surgical targets. The resulting augmented reality environment fuses the pre-operative cardiac model with the intra-operative real-time US images with approximately 5 mm accuracy for structures located in the vicinity of the valvular region. Therefore, we strongly believe that our augmented virtual environment significantly 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, Augmented Virtual Reality, Data Integration for the Clinic/OR. 1. INTRODUCTION Significant developments in both research and technology have led to extensive use of minimally-invasive ap- proaches in surgical interventions by employing robotic and laparoscopic technologies to minimize tissue expo- sure and reduce incision size, in the attempt to reduce patient trauma, shorten recovery times, and lower health care costs. However, when looking at the progression of cardiac procedures, it seems that the translation to minimally invasiveness has been somewhat delayed. Endoscopy-based techniques have been established for epi- cardial interventions, 1 especially when fused with pre-operative three-dimensional (3D) computed tomography (CT) or magnetic resonance (MR) images. 2 However, most complex procedures that require the surgeon to gain Further author information: Cristian A. Linte (E-mail: clinte@imaging.robarts.ca) Terry M. Peters (E-mail: tpeters@imaging.robarts.ca) Imaging Research Labs, Robarts Research Institute: 100 Perth Dr., P.O.Box: 5015, London ON N6A 5K8 Canada. Medical Imaging 2008: Visualization, Image-guided Procedures, and Modeling, edited by Michael I. Miga, Kevin Robert Cleary, Proc. of SPIE Vol. 6918, 69180D, (2008) 1605-7422/08/$18 · doi: 10.1117/12.772028 Proc. of SPIE Vol. 6918 69180D-1 2008 SPIE Digital Library -- Subscriber Archive Copy