Detecting human articular cartilage degeneration in its early stage with polarization-sensitive optical coherence tomography.

Xin Zhou,Shuo Tang,Lin Huang,Sina Maloufi,Rizhi Wang,Xiao Yang,Hanadi Alousaimi,Qihao Liu,Felipe Eltit

doi:10.1364/boe.387242

Abstract

Detecting articular cartilage (AC) degeneration in its early stage plays a critical role in the diagnosis and treatment of osteoarthritis (OA). Polarization-sensitive optical coherence tomography (PS-OCT) is sensitive to the alteration and disruption of collagen organization that happens during OA progression. This study proposes an effective OA evaluating method based on PS-OCT imaging. A slope-based analysis is applied on the phase retardation images to segment articular cartilage into three zones along the depth direction. The boundaries and birefringence coefficients (BRCs) of each zone are quantified. Two parameters, namely phase homogeneity index (PHI) and zonal distinguishability (Dz), are further developed to quantify the fluctuation within each zone and the zone-to-zone variation of the tissue birefringence properties. The PS-OCT based evaluating method then combines PHI and Dz to provide a G PS score for the severity of OA. The proposed method is applied to human hip joint samples and the results are compared with the grading by histology images. The G PS score shows very strong statistical significance in differentiating different stages of OA. Compared to using the BRC of each zone or a single BRC for the entire depth, the G PS score shows great improvement in differentiating early-stage OA. The proposed method is shown to have great potential to be developed as a clinical tool for detecting OA.

Highlights

Osteoarthritis (OA) is the most common degenerative joint disease [1]
The disruptions of collagen organization can be revealed by Polarization-sensitive optical coherence tomography (PS-Optical coherence tomography (OCT)) phase retardation images, which are shown in Figs. 2(g)–2(i), respectively
Previous studies based on PS-OCT have used a single slope (w-birefringence coefficients (BRCs)) or related features to quantify cartilage degeneration, which did not consider the zone-based extracellular matrix (ECM) distribution and disruption [14,17]

Summary

Introduction

Symptoms of OA include debilitating pain, tenderness, and stiffness of joint caused by gradual break down of articular cartilage Those symptoms usually occur when the disease is already in its late-stage so that the patients have no other options than pain management or surgical intervention (e.g. total joint replacement) [2,3,4]. At the beginning of cartilage degeneration, changes only happen at the micro-scale, such as alteration in collagen fibril network and depletion of proteoglycan content [5]. Those changes contribute accumulatively to the gradual destruction of cartilage extracellular matrix (ECM) [6]. A high-resolution imaging technique is needed for detecting early-stage OA

Methods

Results

Conclusion