Birefringence imaging for optical sensing of tissue damage

We present an automated technique to detect and quantify damage to biological tissue by sensing changes in the tissue's optical birefringence. Birefringence is a property of many types of tissue, which decreases with damage. Using a polarisation-sensitive optical coherence tomography scanner, the method first acquires a 3D scan of the area of tissue under analysis. By calculating the birefringence at each location on the surface of the tissue, we build a 2D image indicative of the biological microstructure, with areas of abnormally low birefringence indicating tissue damage. The technique is demonstrated using a model of localised thermal damage on porcine tendon. The resulting birefringence images are validated against a histological gold standard, showing strong correspondence between areas of low and high birefringence, and areas of damaged and undamaged tissue respectively