Eurographics Workshop on Visual Computing for Biology and Medicine (2021) S. Oeltze-Jafra, N. N. Smit, and B. Sommer (Editors) AR-Assisted Craniotomy Planning for Tumour Resection Joost Wooning 1 and Mohamed Benmahdjoub 2 and Theo van Walsum 2 and Ricardo Marroquim 1 1 Delft University of Technology, Netherlands 2 Erasmus MC, Netherlands Abstract Craniotomy is a procedure where neurosurgeons open the patient’s skull to gain direct access to the brain. The craniotomy’s position defines the access path from the skull surface to the tumour and, consequently, the healthy brain tissue to be removed to reach the tumour. This is a complex procedure where a neurosurgeon is required to mentally reconstruct spatial relations of important brain structures to avoid removing them as much as possible. We propose a visualisation method using Augmented Reality to assist in the planning of a craniotomy. The goal of this study is to visualise important brain structures aligned with the physical position of the patient and to allow a better perception of the spatial relations of the structures. Additionally, a heat map was developed that is projected on top of the skull to provide a quick overview of the structures between a chosen location on the skull and the tumour. In the experiments, tracking accuracy was assessed, and colour maps were assessed for use in an AR device. Additionally, we conducted a user study amongst neurosurgeons and surgeons from other fields to evaluate the proposed visualisation using a phantom head. Most participants indeed agree that the visualisation can assist in planning a craniotomy and feedback on future improvements towards the clinical scenario was collected. (see https://www.acm.org/publications/class-2012) CCS Concepts • Human-centered computing → Scientific visualization; Heat maps; • Applied computing → Life and medical sciences; 1. Introduction Figure 1: An example of our AR visualisation to plan a craniotomy. A phantom skull is used for our evaluations. To remove a brain tumour, sometimes it is necessary for surgeons to gain direct access to the brain by making an opening in the skull. The procedure of creating this opening in the skull is called a cran- iotomy. Often, most of the healthy tissue between the skull opening and the tumour is removed, hence, to minimise damaging important brain tissue, this access path needs to be carefully planned. For this task imaging techniques are frequently used and specific structures are segmented. A neurosurgeon then looks at important structures in the brain which should be avoided, such as vessels and certain brain areas and fibres linked to specific neurological functions. Commonly, surgical navigation systems are used to align the im- age data to the patient, often using landmarks [CDS ∗ 19], which allow to locate specific positions in the MRI data on physical po- sitions on the patient. Surgeons can then directly draw the cran- iotomy location on the head of the patient before performing the actual intervention. A downside of current surgical navigation methods is that the surgeon must constantly look at a screen instead of the patient, reducing hand-eye coordination and requiring more experience [HTB ∗ 17, VMR ∗ 14]. Furthermore, most navigation systems use a regular display, which can make it difficult to convey all spatial in- formation of the 3D structures. Augmented reality (AR) has great potential in improving this procedure in several ways. AR allows to superpose information di- rectly on the patient, giving greater context and avoiding deviating © 2021 The Author(s) Eurographics Proceedings © 2021 The Eurographics Association. DOI: 10.2312/vcbm.20211353 https://diglib.eg.org https://www.eg.org