The talk presents a PhD proposal that was recently submitted to the Jacobs University in Bremen. The aim of the PhD project is providing new computer-aided techniques in the field of surgical planning and intraoperative support for liver surgery. Liver surgery planning has become an essential tool in the clinical routine. Based on computational models derived from radiologic images of the patient, surgeons can simulate and assess different resection strategies before an intervention. Thanks to recent advances in image-guided surgery, an adequate transfer of this planning information to the operative site is possible.



The PhD project is divided into two parts. The first part introduces new techniques in the field of risk assessment for liver surgery. One the one hand, the determination of safety margins around tumors is addressed. The determination of optimal safety margins in the liver is a challenging task for a surgeon. The relation to the intrahepatic vascular anatomy and the amount of remnant liver volume are important factors when deciding whether a tumor-free safety margin can be achieved. Therefore, methods to define uniform and non-uniform safety margins around tumors are proposed. The robustness and sensitivity of vascular risk distribution is considered in this context. On the other hand, the generation of resection proposals is addressed. Virtual resection planning is mostly still done completely manually, in that the user defines the orientation and shape of the resection surface by drawing and dragging using a computer mouse. To this end, techniques to generate resection proposals automatically are presented.



The second part addresses the field of image-guided liver surgery. First, new visualization techniques designed for intraoperative use are introduced. Intraoperative visualizations have to follow specific requirements such as the workflow and cognitive load of the surgeon, which together call for a context-driven reduction of complexity and a focus on critical areas. Therefore, a visualization method for quickly assessing registration errors, risk maps for resection guidance, and an approach to augment the surgical view with planning information are introduced. Second, techniques for auditory support for image-guided liver surgery are presented. Auditory support reduces the dependency on visual presentations, freeing the surgeon to focus attention on the situs rather than on a video monitor. Third, an intraoperative adaptation of the surgical plan is addressed. A tool to quickly adapt risk analyses and resection plans in case of intraoperatively detected tumors is proposed. In this context, appropriate interfaces for surgeon-computer interaction are presented.