Development of a novel line scanner for speckle contrast diffuse correlation tomography of microvascular blood flow

Abstract

Partial thickness burn wounds extend partially through the dermis, leaving many pain receptors intact and making the injuries very painful. Due to the painfulness, quick assessment of the burn depth is important to not delay surgery of the wound if needed. Laser speckle imaging (LSI) of skin blood flow can be helpful in finding severe coagulation zones with impaired blood flow. However, LSI measurements are typically too superficial to properly reach the full depth of adult dermis and cannot resolve the flow in depth. Diffuse correlation spectroscopy (DCS) uses varying source-detector separations to allow differentiation of flow depths but requires time-consuming 2D scanning to form an image of the burn area. We here present a prototype for a hybrid DCS and LSI technique called speckle contrast Diffuse Correlation Tomography (scDCT) with the novel approach of using a laser line as a source. This will allow for fast 1D scanning to perform 3D tomographic imaging, making quantitative estimates of the depth and area of the coagulation zone from burn wounds. Simulations and experimental results from a volumetric flow phantom show promise to differentiate flows at different depths. The aim is to create a system that will provide more quantitative estimates of coagulation depth in partial thickness burn wounds to better estimate when surgery is needed.