Assessing the progression of systemic sclerosis by monitoring the tissue optic axis using PS-OCT

Abstract

The clinical assessment of fibrosis is critical to the diagnosis and management of patients with systemic sclerosis. Current clinical standards for patient assessment is to use skin fibrosis as an indicator of organ involvement, though this approach is highly subjective and relies on manual palpation. The development of a new method for accurately quantifying collagen content may therefore significantly improve the accuracy of the traditional skin score in patients with systemic sclerosis and may additionally aid in the monitoring of anti-fibrotic therapies in clinical practice. Polarization-sensitive optical coherence tomography (pS-oct) is a high-speed volumetric imaging modality that can be used to assess birefringent tissues including collagen. In this work we demonstrate a novel computational approach using PS-OCT for the assessment of fibrosis. This approach, based on the measured distribution of optic axis values associated with a given volume of collagen orientation, characterizes fibrotic changes independently from the depth of the region of interest in the tissue. This approach has the potential to accurately quantify collagen content and orientation faster and more robustly compared to traditional pS-oct metrics. We investigate the viability of this approach for assessing the development of fibrosis in a bleomycin induced skin fibrosis mouse model.

Integrated Optical Coherence Tomography and Deep Learning for Evaluating of the Injectable Hydrogel on Skin Wound Healing

“…The phase retardation image represents cumulative phase retardation due to the birefringence inside the tissue because the difference in phase shift between two characteristic polarization states of backscattered light from the tissue is altered by the tissue birefringence. Therefore, PS-OCT can characterize the amount of collagen by measuring the polarization parameters of the sample, such as phase retardation and degree of polarization (DOP), which will help us to observe the growth direction and recovery of the wound [67].…”

Skin involvement in early diffuse cutaneous systemic sclerosis: an unmet clinical need

“…Although OCT can provide higher imaging resolution than ultrasonography-based techniques, currently it has limited imaging depth, which complicates assessment of lower layers of dermis in certain body areas, underscoring the need for further development in this area. Polarization-sensitive OCT (PS-OCT) 67 is an extension to OCT that involves the measurement of birefringence (an optical property of collagen) in addition to skin thickness. Birefringence can be considered a measure of skin ‘heterogeneity’ and, therefore, potentially a measure of fibrosis.…”

Orthogonal‐polarization‐gating optical coherence tomography for human sweat ducts in vivo

“…Tissue optical properties containing total attenuation, scattering coefficients and optical thickness can be noninvasive measured based on OCT. [ 11–14 ] Cumulative or local phase retardance and optical axis can be obtained based on polarization sensitive (PS)‐OCT. [ 15–18 ]…”