title: Three-dimensional optic axis determination using variable-incidence-angle polarization-optical coherence tomography.
abstract: Polarization optical coherence tomography (PSOCT) is a powerful technique to nondestructively map the retardance and fast-axis orientation of birefringent biological tissues. Previous studies have concentrated on the case where the optic axis lies on the plane of the surface. We describe a method to determine the polar angle of the optic axis of a uniaxial birefringent tissue by making PSOCT measurements with a number of incident illumination directions. The method is validated on equine flexor tendon, yielding a variability of 4% for the true birefringence and 3% for the polar angle. We use the method to map the polar angle of fibers in the transitional region of equine cartilage.
authors.affiliation: Biomedical Physics Group, University of Exeter, Stocker Road, Exeter EX4 4QL, UK.
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Ugryumova
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Gangnus
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Matcher
mesh_terms: D000818:Animals; D016880:Anisotropy; D006736:Horses; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D012031:Refractometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013710:Tendons / Q000033:anatomy & histology* / Q000502:physiology*; D041623:Tomography, Optical Coherence / Q000379:methods*