Parametric imaging of attenuation by optical coherence tomography: review of models, methods, and clinical translation

Abstract

Significance: Optical coherence tomography (OCT) provides cross-sectional and volumetric images of backscattering from biological tissue that reveal the tissue morphology. The strength of the scattering, characterized by an attenuation coefficient, represents an alternative and complementary tissue optical property, which can be characterized by parametric imaging of the OCT attenuation coefficient. Over the last 15 years, a multitude of studies have been reported seeking to advance methods to determine the OCT attenuation coefficient and developing them toward clinical applications. Aim: Our review provides an overview of the main models and methods, their assumptions and applicability, together with a survey of preclinical and clinical demonstrations and their translation potential. Results: The use of the attenuation coefficient, particularly when presented in the form of parametric en face images, is shown to be applicable in various medical fields. Most studies show the promise of the OCT attenuation coefficient in differentiating between tissues of clinical interest but vary widely in approach. Conclusions: As a future step, a consensus on the model and method used for the determination of the attenuation coefficient is an important precursor to large-scale studies. With our review, we hope to provide a basis for discussion toward establishing this consensus.

Bayesian analysis of depth resolved OCT attenuation coefficients

“…Using Mie theory, the scattering cross section is given by and the total attenuation coefficient is 20 . This value is realistic for tissue 21 , 29 . An OCT B-scan of the phantom is shown in Fig.…”

Application of OCT‐Derived Attenuation Coefficient in Acute Burn‐Damaged Skin

“…To estimate OAC, several models have been proposed to describe the OCT signal, including single-scattering model, multiple-scattering model, and full electromagnetic wave model [36]. Among them, the singlescattering model is the most common model.…”

“…Furthermore, in addition to OAC being used to improve imaging contrast, it can also serve as a physical parameter for evaluating tissue characteristics [36] because changes in tissue morphology and content can alter a tissue's OAC. Previous works have shown promising results in the application of OAC to monitoring skin wound healing [37,38], assessing burn scars [39,40], identifying brain cancer [41], and evaluating brain damage [42].…”

1.7-Micron Optical Coherence Tomography Angiography for Characterization of Skin Lesions–A Feasibility Study

“…To further improve the accuracy, more parameters should be investigated to quantify the changes in structure, vascular morphology, and chemical composition based on OCT and OCTA images. For example, the measurement of reflectivity and attenuation coefficient could provide a quantitative analysis of the skin's physical alterations [35]. To provide comprehensive characterization, optical coherence elastography could be incorporated to map the biomechanical property of tissue [36][37][38].…”