Development of an Augmented Microscope for Image Guided Surgery in the Brain

Abstract

Vascular malformations and cancer remain the major brain pathologies that often require surgical treatment. Glioblastoma, classified as a grade IV astrocytoma, is a highly malignant cancer of the brain that has a median survival of 1-2 years, with more aggressive forms having median survival less than 14 months. These statistics include standard treatment protocols that include surgery followed with adjunctive chemotherapy and radiation treatment. Vascular malformations encompass multiple, more specific pathologies including arteriovenous malformation, cavernous malformation, mixed malformations, telangiectasis, vein of Galen malformation, and venous malformations. Treatment of either vascular anomalies or cancer can benefit from improved image guided surgery technologies. Surgical image guidance has continually been improving over the decades since the introduction of the microscope. New technologies including endoscopic cameras and non-invasive imaging (e.g., computed tomography and magnetic resonance imaging) have led to paradigm shifts in how disease is diagnosed and treated. However, even with the numerous advancements in imaging technologies, the microscope still remains the most used and required imaging technology in the neurosurgical operating suite. There remains to be a system that can match ergonomics and visualization that the operative microscope provides. The operative microscope retains all aspects of 3-D vision while magnifying and focusing the field of view for the surgeon. Cameras, light sources, and other surgical equipment have been added to the plethora of attachments now available for the operative microscope. This work is organized into three specific aims that collectively present the development of a new technology focused on improving image guided surgery coupled with a novel contrast agent. The first aim will present the development of an augmented microscope that is capable of augmenting the field of view in the oculars with NIR fluorescence information. The second aim will provide a performance characterization of the augmented microscope through numerous examples and demonstrations both in vitro and in vivo. The third aim will discuss a novel contrast agent, plasmon resonant liposomes, that can be coupled with the augmented microscope for improving visualization in vivo. The combination of new imaging technologies and contrast agents can improve visualization of pathologies in the brain, like cancer, and lead to better margin assessment and surgical outcomes.