Parametric imaging of collagen structural changes in human osteoarthritic cartilage using optical polarization tractography

Abstract

Collagen degeneration is an important pathological feature of osteoarthritis. The purpose of this study is to investigate whether the polarization-sensitive optical coherence tomography (PSOCT)-based optical polarization tractography (OPT) can be useful in imaging collagen structural changes in human osteoarthritic cartilage samples. OPT eliminated the banding artifacts in conventional PSOCT by calculating the depth-resolved local birefringence and fiber orientation. A close comparison between OPT and PSOCT showed that OPT provided improved visualization and characterization of the zonal structure in human cartilage. Experimental results obtained in this study also underlined the importance of knowing the collagen fiber orientation in conventional polarized light microscopy assessment. In addition, parametric OPT imaging was achieved by quantifying the surface roughness, birefringence, and fiber dispersion in the superficial zone of the cartilage. These quantitative parametric images provided complementary information on the structural changes in cartilage, which can be useful for a comprehensive evaluation of collagen damage in osteoarthritic cartilage.

Automatic quantification of microscopic heart damage in a mouse model of Duchenne muscular dystrophy using optical polarization tractography

“…The aforementioned image processing procedure was applied to the entire depth‐resolved en face images of fiber orientation obtained in OPT. To construct the 3D image of the heart damage, the heart surface was first identified using an intensity threshold‐based segmentation method . Next, all the image data were polar‐transformed based on the corresponding rotation position in the C‐scan as described in our previous studies .…”

High-resolution 3D tractography of fibrous tissue based on polarization-sensitive optical coherence tomography

“…77 As shown in a recent study in cartilage, the different imaging parameters obtained in OPT may have different pathological originations. 46 If fully understood, such multi-parametric imaging capability can provide a powerful tool for tissue characterization and classification.…”

Polarized reflectance from articular cartilage depends upon superficial zone collagen network microstructure

“…Studies using polarization-sensitive tomographic approaches are complicated by the dependence of signal on specimen microstructural orientation with respect to input polarization [8,9], and by the need to acquire multiple adjacent tomograms to build an image of a larger volume of tissue. Optical polarization tractography (OPT) creates three-dimensional maps of microstructure in tissue from Jones matrix polarization parameters, including three-dimensional articular cartilage zonal architecture and surface roughness [10][11][12][13], skeletal muscle fibers, blood vessels, and heart tissue [12,[14][15][16]. In contrast to tomographic and computational approaches, widefield reflectance microscopy rapidly images large areas of the cartilage surface and, with added polarizers, noninvasively assesses subsurface birefringent features, which makes it potentially useful in the evaluation of cartilage explants and of multiple sites within intact joints.…”

“…The alignment of the collagen network within the superficial zone has been mapped using split lines, and contributes to the superficial zone orthotropic tensile modulus [25]. Computational modeling and optical analyses of the superficial zone following mechanical loading and in pathology and aging suggest superficial zone collagen microstructural alignment is functionally important [13,[26][27][28][29].…”