Collaborative Research: Ultrasonically-enhanced optical coherence tomography for functional phase imaging

About This Grant

Imaging inside the human body can reveal important information for diagnosis and treatment of disease. To obtain a high-quality image, light is usually projected from outside the body using external lenses and microscopes. The imaging depth is limited since light cannot be delivered deep into the tissue from outside. Lens and endoscopes can be inserted into the tissue to mitigate this issue. However, this is invasive and can cause damage. This project will use non-invasive ultrasound waves to guide and focus light through the tissue without the need for inserting a physical lens. This approach will allow for high-resolution imaging in parts of the body, like the brain, that cannot be achieved with MRI, while imaging over a larger volume than possible with a traditional microscope. The project will also help develop the next generation of young scientists and engineers with an interest in ultrasound and optical technologies. This project will develop the first ultrasonically-enhanced swept source optical coherence tomography (ueSS-OCT) system for label-free optical imaging of tissue structure and function with near beam waist limited lateral resolution over an extended depth range. Ultrasound waves can locally change the refractive index profile in tissue to sculpt in situ virtual optical waveguides that can focus and steer light. The project has three main objectives: (1) to utilize the unique interplay between these in situ lenses and SS-OCT detection for beam waist limited resolution over 2 mm of sub-surface structural imaging depth and (2) up to 2 mm of functional phase-resolved imaging with shot noise limited phase resolution with an extended flow velocity range. These advances will be validated by (3) detection of functional activation in the well-established animal model of somatosensory activation in response to whisker stimulation. This project will demonstrate a novel imaging paradigm in which external focusing optics can be replaced by in situ optical waveguides formed within the tissue itself. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.