American Journal of Biomedical Engineering 2013, 3(6): 169-174 DOI: 10.5923/j.ajbe.20130306.05 A Mobile Augmented Reality Application for Image Guidance of Neurosurgical Interventions Matt Kramers 1,2,* , Ryan Armstrong 1 , Saee d M. Bakhs hmand 1 , Aaron Fe ns te r 1,2 , Sandrine de Ribaupie rre 1,3,4 , Roy Eagleson 1,4 1 Biomedical Engineering Graduate Program, University of Western Ontario, London, N6A3K7, Canada 2 Robarts Research Institute, University of Western Ontario, London, N6A3K7, Canada 3 Department of Clinical Neurological Sciences, University of Western Ontario, London, N6A3K7, Canada 4 Department of Electrical and Computer Engineering, University of Western Ontario, London, N6A3K7, Canada Abstract Image guidance for complex surgical procedures is gaining popularity within operating rooms. Providing the appropriate contextual information to aid in navigation can reduce cognitive load on surgeons, thus reducing surgical error. To date, clinical implementations of image guidance have required extensive equipment, setup and technical expertise to operate precluding their use when treating acute conditions in the intensive care unit. We present an application targeted at mobile platforms that utilizes augmented reality and image-based tracking in order to add preoperative contextual information to neurosurgical procedures, specifically spatial information. A pilot evaluation was performed to examine accuracy of the system. Initial results show increased accuracy for a targeting task with the aid of the visualization. Keywords Image Guidance, Augmented Reality, Neurosurgery, Graphics, Segmentation 1. Introduction Placing an external ventricular drain (EVD) is a fundamental neurosurgical procedure performed to treat acute hydrocephalus – a condition characterized by an accumulation of cerebrospinal fluid within the ventricular system, either due to obstruction or by a problem of reabsorption[1, 2]. The procedure consists of drilling a burr-hole in the skull, followed by a bling placement of an external ventricular drain using external landmarks for guidance. This procedure allows drainage of cerebrospinal fluid to relieve intracranial pressure. While most neurosurgical interventions are usually performed in an operating room (OR) while the patient is under sedation[3], this is rarely the case for this procedure. Since the insertion of an EVD is usually performed on critically ill patients (either for acute hydrocephalus or after a trauma), the predominant difficulty involves transportation of the patient[4] mostly due to life-support equipment[5]. To accommodate such a scenario, manual operation of mobile drills for burr-hole trephine can be performed within the Intensive Care Unit or in the Emergency room. While advantageous in avoiding the difficulties in relocation to the OR, this technique precludes the use of certain immobile * Corresponding author: mattkramers@gmail.com (Matt Kramers) Published online at http://journal.sapub.org/ajbe Copyright © 2013 Scientific & Academic Publishing. All Rights Reserved equipment present within the OR. While external ventricular drain placements are among the most common and basic of neurosurgical procedures, they are generally performed free-hand, relying on surface landmarks on the patient as well as the spatial reasoning of the operating surgeon to determine optimal trajectory of tools within the complex workspace. While it might be relatively easy to target large ventricles placed in a normal anatomical position, most patients will have small ventricles with some anatomical variation, possibly displaced by lesions occurring after the trauma. As a result of navigational error due to free-hand placement, a number of complications can occur, including malposition, non-function, infection and haemorrhage[6]. While neurosurgeons generally consider the manual procedure to be safe, a number of studies have identified the technique as suboptimal[7, 8, 9]. In addition, this procedure is often performed by junior residents who are on-call. Indeed, many of these complications are a result navigational error, often requiring repositioning of the EVD into the ventricular system. In addition to the complications resulting from such misplacements, the procedure time is increased and additional, unnecessary tissue damage occurs. The goal of this project was to create a neurosurgical guidance system to aid in visualization of the ventricles in order to perform the procedure less blindly. This was achieved through the use of an augmented reality (AR) viewport to provide inner anatomical context to the surgeon during navigation. As CT scans are standard for such