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Optical coherence tomography (OCT) is a non-invasive and non-contact imaging technique that uses the reflection of light waves for tissue imaging. Compared to all other OCT variants, the swept-source OCT (SS-OCT) configuration offers higher imaging speed, better signal-to-noise ratio, and more resolution. Despite its numerous advantages, SS-OCT greatly suffers from limited contrast and reduced penetration ability. Over the years, several nanoparticles (NPs) like AgNP, TiO2, ZnO, etc have been exploited extensively as exogenous contrast agents to enhance the image contrast. Subsequently, herein, we have presented gadolinium oxide (Gd2O3) as a potential exogenous contrast agent for 3D non-invasive depth-resolved imaging of animal (chicken breast) tissue using an in-house developed SS-OCT system with centre wavelength of 1060 nm. In this work, OCT imaging of agar filled capillary tubes (phantoms) and chicken breast tissue (in vitro) was performed both with and without the application of Gd2O3 NPs. Scattering coefficient and contrast-to-noise ratio (CNR) calculations were done to study the effect of Gd2O3 NPs on the tissue sample at different time exposures. Post analysing the OCT images, a significant increase, in contrast, observed with time, where both the scattering coefficient (0.4879 mm−1 to 1.3782 mm−1) and the CNR of OCT B-scans (12.42 dB to 42.21 dB) increased substantially. [ABSTRACT FROM AUTHOR]

We present a non-invasive three-dimensional depth-resolved micro-structure and micro-vasculature imaging of a human fingernail-fold with a swept-source optical coherence tomography (ssOCT) system at a 1064 nm center wavelength. A phase variance OCT angiography (OCTA) method was implemented for motion contrast OCT imaging. A Fourier-domain mode-locked light source with an A-scan rate of 1.7 MHz (1 700 000 A-scans s−1) was utilized for imaging. The experimental setup demonstrates OCT and OCTA imaging with an area of ~5 mm  ×  5 mm (within the Nyquist limit). Details of the ssOCTA system such as system parameters, scanning protocols, acquisition time, challenges, and scanning density are discussed. The selected features of the nail-fold structure and vascular networks are also deliberated. The system has potential for real-time monitoring of transdermal drug delivery, and the management and diagnosis of various diseases such as connective tissue diseases and Raynaud’s phenomenon. [ABSTRACT FROM AUTHOR]

Optical coherence tomography (OCT) is a rapidly evolving, robust technology that has profoundly changed the practice of medical imaging. Swept source OCT (SSOCT) combines the standard time domain and the spatially encoded frequency domain OCT. We have employed a high-speed SSOCT system that utilizes a swept source laser with an A-scan rate of 100 kHz and a central wavelength of 1060 nm for the imaging of the tissue. SSOCT at 1060 nm allows for high penetration in the tissue. TiO2 nanoparticles (NPs) are mostly used for various experimental purposes as an exogenous imaging contrast agent. The in vitro imaging of chicken breast tissue is performed with and without the application of TiO2 NPs for exogenous contrast. Characterization of the chemically synthesized TiO2 NPs was done with dynamic light scattering and a scanning electron microscope method. The effect of TiO2 is studied at different exposure times. A significant improvement in the contrast to noise ratio has been observed through the in vitro imaging of a TiO2 treated tissue. [ABSTRACT FROM AUTHOR]

We present noninvasive three-dimensional depth-resolved imaging of animal tissue with a swept-source optical coherence tomography system at 1064 nm center wavelength and silver nanoparticles (AgNPs) as a potential contrast agent. A swept-source laser light source is used to enable an imaging rate of 100 kHz (100 000 A-scans s−1). Swept-source optical coherence tomography is a new variant of the optical coherence tomography (OCT) technique, offering unique advantages in terms of sensitivity, reduction of motion artifacts, etc. To enhance the contrast of an OCT image, AgNPs are utilized as an exogeneous contrast agent. AgNPs are synthesized using a modified Tollens method and characterization is done by UV–vis spectroscopy, dynamic light scattering, scanning electron microscopy and energy dispersive x-ray spectroscopy. In vitro imaging of chicken breast tissue, with and without the application of AgNPs, is performed. The effect of AgNPs is studied with different exposure times. A mathematical model is also built to calculate changes in the local scattering coefficient of tissue from OCT images. A quantitative estimation of scattering coefficient and contrast is performed for tissues with and without application of AgNPs. Significant improvement in contrast and increase in scattering coefficient with time is observed. [ABSTRACT FROM AUTHOR]