Topographical variations in the polarization sensitivity of articular cartilage as determined by polarization-sensitive optical coherence tomography and polarized light microscopy

Abstract

To understand the influence of topographical variations in collagen fibril orientation of articular cartilage on optical phase images of polarization-sensitive optical coherence tomography (PS-OCT), we use polarized light microscopy (PLM) to quantify the orientation and phase retardation of the collagen architecture in cartilage at the same locations imaged by PS-OCT. The PS-OCT experiments demonstrate that articular cartilage has normal variations in polarization sensitivity at different locations over an intact bovine tibial plateau. Articular cartilage is not polarization sensitive along the vertical axis on the medial edge and central areas of the joint surface, but becomes polarization sensitive on the lateral edge of the tibia. This difference in optical phase retardation, as demonstrated by PS-OCT, is verified by PLM to be caused by differences in collagen fibril orientation at different locations of the tibial plateau. This study demonstrates that normal topographical variations in the collagen architecture of articular cartilage within a joint have a profound influence on the optical phase retardation detected by PS-OCT imaging, and therefore must be understood and mapped for specific joints before PS-OCT imaging can be used for the evaluation of the health status of individual joint surfaces.

The role of interstitial fluid pressurization in articular cartilage lubrication

“…The articular layer exhibits compositional heterogeneity from the surface to the subchondral bone; it is typically divided into three regions commonly called the superficial, middle and deep zones (SZ, MZ and DZ, respectively) (Maroudas, 1979; Mow and Ratcliffe, 1997). The delineation between these zones is often determined on the basis of the orientation of the collagen fibrils, which may be determined via polarized light microscopy (PLM), magnetic resonance imaging (MRI), or Fourier Transform infra-red imaging (FTIRI) (Bi et al, 2005; Nieminen et al, 2001; Nissi et al, 2006; Xia et al, 2007; Xie et al, 2008). …”

Slope-based segmentation of articular cartilage using polarization-sensitive optical coherence tomography phase retardation image

“…Similar observations have also been reported by others that the phase retardation in the deep area may accumulate relatively fast in some locations of cartilage samples. 15,26 However, in some other reported literature, 14,16,20 low birefringence has been found in deep zone at normal incidence. The difference in the results shows that the quantification of birefringence in the deep zone is quite sensitive, and it may depend on the types of samples, topographical locations, illumination angles, etc.…”

“…By PS-OCT, the tissue birefringence in articular cartilage was found to depend on not only the healthy states, but also the light illumination direction 14 and topographical location. 15 Therefore, a more comprehensive quantitative method is needed to distinguish the different severities of DJD. Brill et al 16 quantified the features in the banding pattern of phase retardation image, such as the width and height of the bands and the total number of bands.…”

Polarization Sensitive Optical Coherence Tomography: A Review of Technology and Applications

“…In an in vivo study on human knee joints prior to partial or total joint replacement treatment, reduced birefringence was found in degenerated cartilage [196]. PS-OCT images of one proximal joint surface of bovine tibia are shown in Figure 9d [188]. PS-OCT using variable incidence angles was further used to investigate the 3D architecture of the collagen fiber network in cartilage [197,198].…”