Jeffrey Watson Abstracts
Jeffrey Watson
Ph.D. Candidate
Biomedical Engineering GIDP
Photonics West-Physics & Simulation of Optoelectronic Devices XXIV
San Francisco, CA
February 13-18, 2016
Professional Abstract
Abstract for Lay Audience
"Intraoperative Vascular Imaging with Augmented Microscopy"
Authors: Jeffrey R Watson1, Nikolay Martirosyan2,Summer Garland1 G. Michael Lemole Jr.2, Marek Romanowski1
1Department of Biomedical Engineering
2Department of Surgery, Division of Neurosurgery University of Arizona
Tucson, AZ 85721-0240
A common difficulty in intracranial vascular angiography is the inability to simultaneously visualize and manipulate vascular anatomy upon near-infrared contrast injection. We previously introduced the augmented microscope with near- infrared fluorescence detection. Here we report on application of augmented microscopy in guiding vascular procedures in neurosurgery.
We used normal Wistar rats to represent normal intracranial vasculature and orthotopically implanted C6 cells to represent vascular anomalies. Two near- infrared agents were compared, FDA approved indocyanine green (ICG) and gold- coated, plasmon-resonant liposomes incorporating lipophilic near-infrared dye (Au- IR-liposomes), developed earlier in our laboratory. While ICG is standard in clinical angiography, the Au-IR-liposomes present a new class of light-activated functional nanoparticles that enable spatially and temporally controlled delivery of pharmaceuticals or activating photothermal ablation. We demonstrated performance of augmented microscopy in several surgical procedures including craniotomy, intracranial angiography, and tumor resection. Augmented images of near-infrared contrast agent distribution in vasculature, as seen by the operating surgeon, were acquired through the microscope optical path.
Vascular imaging under augmented microscopy guidance was compared to current surgical image guidance technique, i.e., standard bright-field microscopy. The augmented fluorescence channel improved accuracy of locating vessels of interest and reduced surgical time through a more efficient image guidance system. Though the vascular system remains the main route for delivering contrasts and therapies, we envision augmented microscopy being applied to agents that extravasate or localize to various solid tissues. In combination with new types of functional contrast agents, augmented microscopy will lead to improved surgical outcomes and new image guided surgery opportunities.
100- -word summary:
A common difficulty in intracranial vascular angiography is the inability to simultaneously visualize and manipulate vascular anatomy upon near-infrared contrast injection. The augmented microscope was designed to address this concern. Here, vascular imaging under augmented microscopy guidance was compared to current surgical image guidance technique, i.e., standard bright-field microscopy. The augmented fluorescence channel improved accuracy of locating vessels of interest and reduced surgical time through a more efficient image guidance system. Though the vascular system remains the main route for delivering contrasts and therapies, we envision augmented microscopy being applied to agents that extravasate or localize to various solid tissues.
Near-infrared contrast agents may improve the outcome of many surgical procedures. However, their clinical use requires specialized instrumentation to convert the near-infrared signal into a visible image. This requirement is further complicated by the fact that many surgical procedures are performed under dedicated surgical microscopes. Here we describe the prototype augmented microscope that is capable of producing an overlay of bright-field (real) and near-infrared (synthetic) images within the ocular of the microscope, with a user-controlled balance of features. Performance of the augmented microscope was evaluated in various models and in vivo. We have shown sensitivity to clinical near-infrared contrast agents (e.g. indocyanine green) that is 1/1000th of the current clinical dose injected into patients during surgery. We have used the augmented microscope to assist the surgeon in vascular and oncological surgeries on a rat model. In both cases, we demonstrated how the microscope performs compared to the current clinical techniques employed. Using a novel contrast agent previously developed in the Romanowski lab, we have imaged vascular distribution in the rat model. Fully developed, the augmented microscope will improve image guidance in neurosurgical, cerebrovascular, ophthalmic, and other procedures.