|
Polarization sensitive optical coherence tomography (PS-OCT) measures tissue birefringence, while optical coherence elastography (OCE) reveals the mechanical property of the tissue. Since both birefringence and mechanical properties are associated with tissue microstructures such as collagen, simultaneous PS-OCT and OCE measurement will provide useful insight for the tissue microstructures. In this paper, we present a combined PS-OCT and OCE technique.
The PS-OCT is based on Jones matrix OCT theory. It measures a tomography of Jones matrix. Birefringence tomography is then deduced from the Jones matrix. The OCE is obtained with active tissue compression. The tissue compression was performed by a ring piezoelectric (PZT) actuator installed in front of an objective. A glass slip is attached at the fore-end of the PZT to push a tissue. Multiple cross sections were synchronously measured through the glass slip with gradual tissue compression (0 – 12 µm at maximum). The raw Jones matrix tomography consists of 4 complex-valued OCT images. Two of the 4 images (two orthogonal detection polarization images of a single input polarization) are processed by a correlation based tissue displacement-and-deformation analysis method [Kurokawa et al., Opt. Lett., 2153-, 2015]. It provides polarization artifact free cross-sectional maps of (1) axial displacement, (2) lateral displacement, and (3) microstructural deformation.
The method was evaluated by measuring porcine muscle tissues. It was observed that the muscle has subdomains with different deformation properties. In addition, the cross-sectional deformation map distinctively visualized that the muscle and adipose has significantly different deformation properties. Different muscle samples shows different birefringence strength.
|
