Laser Speckle Imaging of Brain Tumor Vasculature

DESCRIPTION (provided by applicant): Approximately 20,500 Americans will be diagnosed with a central nervous system tumor this year. Over half of those diagnosed will lose their lives. The mainstay of treatment for these patients has been surgical resectio n with radiation therapy. More recently, non-invasive pharmacotherapies have been developed to target inhibition of tumor angiogenesis. Evaluation of the vasculature during these treatment options is important and is aided by imaging modalities. However, t he low resolution of ultrasound and cumbersome nature of MRI imaging present significant limitations. In addition, these modalities do not elucidate changes in tumor-associated microvasculature, which is important to investigate for angiogenesis-based rese arch efforts. Thus, brain cancer research and therapeutic interventions would benefit from the development of imaging techniques to view high resolution, high contrast vascular images at the tumor site. We propose a new imaging modality based on the Laser Speckle (LS) phenomenon. LS optical imaging uses the random reflection nature of laser light to track the flow of blood at the vessel level. Unlike other modern imaging modalities, LS imaging does not require the use of a contrast agent and may be used at extremely high resolutions. We propose a Phase I effort focused on obtaining proof- of-concept for this imaging modality. Specifically, we will: Develop an LS imaging system complete with an image processing suite to: 1) enhance the visualization of tumo r-associated microvasculature, and 2) create wide field images to better visualize blood vessels across broader areas of the exposed brain. The microvasculature will be enhanced using a ridge tracking algorithm, and wide field images will be created by sti tching together individual high-resolution images using a mosaicking method. Validate the LS imaging technology in a rodent model of brain tumor by quantifying tumor vasculature using spatial calculations of Mean Vasculature Density and correlating with histological findings. The major milestone of Phase I is to produce high resolution and wide field images of tumor- associated vasculature with histological confirmation. If we are successful, we envision a Phase II effort focused on development of a LS im aging research prototype to track drug therapy and tumor angiogenesis in an animal model. The long-term goal is to build a clinical LS imaging device to improve visualization of surgical treatment in brain cancer patients. PUBLIC HEALTH RELEVANCE: The goal of this project is to develop a novel imaging modality based on laser speckle for evaluating brain tumor angiogenesis. This technology can be used to test new tumor drug therapies and eventually assist with intra-operative vasculature imaging during tumor resection.