Simultaneous elastography and angiography using optical coherence tomography

Optical coherence tomography (OCT) is a non-invasive, label-free imaging modality that generates high-resolution threedimensional images. Based on OCT imaging, optical coherence tomography angiography (OCTA) and optical coherence elastography (OCE) can visualize vascular networks and measure the elastic properties of biological tissues. In previous studies, OCTA and OCE were performed separately, providing either vascular network information or elasticity properties of the tissue. We have developed a simultaneous angiography and elastography method using a simplified sample arm structure. After mechanical pressure is loaded on the sample by a glass plate, the deformation is analyzed by the OCT phase changes, and the elasticity is assessed. Meanwhile, the vascular network is visualized by intensity-based Doppler variance analysis. A transparent flexible reference layer is placed between the glass plate and the tissue, which closely contacts the tissue. Better elasticity measurements can be achieved without affecting vascular imaging. The simultaneous elastography and angiography method was demonstrated by the phantom experiments and rat skin measurements. The results show that the information on the microvascular networks and mechanical properties can be obtained at the same imaging location. The method can provide more comprehensive information on biological tissue for disease diagnosis and treatment monitoring.