In neurovascular surgery, and in particular surgery for arteriovenous malformations (AVMs), the surgeon must map pre-operative images of the patient to the patient on operating room (OR) table in order to understand the topology and locations of vessels below the visible surface. This type of spatial mapping is not trivial, is time consuming, and may be prone to error. Using augmented reality (AR) we can register the microscope/camera image to pre-operative patient data in order to aid the surgeon in understanding the topology, the location and type of vessel lying below the surface of the patient. This may reduce surgical time and increasing surgical precision. In this project as well as studying a mixed reality environment for neuromuscular surgery, we will examine and evaluate which visualization techniques provide the best spatial and depth understanding of the vessels beyond the visible surface.

A: Colour coding of a vascular DS-CTA volume based on blood flow. B: Vessels overlaid on the patient skin prior to draping (left). The AR view is used at this step to help tailor the extent of the craniotomy. On the right we see vessels overlaid on the cortex prior to resection, here the AR view is used to determine the optimal resection corridor. The blue arrows point to the pink markers that indicate the location of deep feeding arteries. The orange arrow indicates the major arterialized vein, shown as red and not blue. C: Different visualization techniques for combining the live camera image (prior to resection) with the virtual vessels (green, red, blue) are shown.The use of simple alpha-blending between the real and virtual worlds does not provide spatial information (top). More sophisticated techniques such as modulating transparency in the area of interest and using edges (from the virtual vessels and/or camera image) and using fog are applied. D: Based on the virtual information the surgeon placed a micropad on the brain surface above a virtual marker representing a deep feeding artery to help with the resection approach and vessel localization.

Publications

M. Kersten-Oertel, M., Gerard, I., Drouin, S., Mok, K., Sirhan, D., Sinclair, D. S. and Collins, D. L. Augmented reality in neurovascular surgery: feasibility and first uses in the operating room. IJCARS (2015): 1–14.

Kersten-Oertel, M., Gerard, I. J., Drouin, S., Mok, K., Sirhan, D., Sinclair, D. S., & Collins, D. L. (2015). Augmented Reality for Specific Neurovascular Surgical Tasks. In Augmented Environments for Computer-Assisted Interventions (pp. 92–103). Springer International Publishing.

M. Kersten-Oertel, I. Gerard, S. Drouin, K. Mok, D. Sirhan, D. Sinclair, D. L. Collins. “Augmented Reality in Neurovascular Surgery: First Experiences.” Augmented Environments for Computer-Assisted Interventions. Lecture Notes in Computer Science Volume 8678, 2014, pp 80–89, 2014.

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