Introduction to the Special Issue on Optical Coherence Tomography (OCT)
Optical Coherence Tomography (OCT) is one of the fastest developing medical imaging technologies that enables non-invasive and non-contact cross-sectional volumetric imaging by detecting the interference formed between the reflected signals from reference mirror and from biological samples. With an ability to perform in vivo “optical biopsy” and provide microscopic structural resolution (1 to 10μm), OCT has been widely used in scientific research as well as clinical diagnosis and management of various diseases, including ophthalmology, dermatology, etc. Furthermore, recent developments such as optical coherence tomography–based angiography (OCTA) has extended OCT applications from pure structural imaging to functional imaging, pushing the OCT development into a new height. Despite decades of development, OCT still faces challenges and is still in its infancy in many areas.
In this Special Issue, one review paper and eleven original research papers are presented. Specifically, Li et al. provided a systematical review of the OCTA based on the inverse SNR and decorrelation features (ID-OCTA), mainly including the OCTA contrast origins, ID-OCTA imaging, quantification and applications.1 Tao et al. conducted a retrospective study of 339 cases of patients who underwent pars plana vitrectomy and intraoperative OCT (iOCT) scan in the past four years and elaborated that iOCT has a significant clinical functionality in vitreoretinal surgery.2 The original studies presented in this issue range from intraoperative OCT angiography (iOCTA) system,3 novel k-domain spline interpolation method in swept-source OCT (SS-OCT) system,4 a method of removing scattering induced retardance in polarization sensitive full field OCT,5 OCT image segmentation and thickness estimation algorithms (including automated retinal layer segmentation algorithm combined with structure interpolation and lateral mean filtering,6 measurement of epidermal thickness of fingertip skin7 as well as quantification of choroidal thickness and vasculature8 based on neural network) to its applications (including monitoring of edema progression in middle cerebral artery occlusion models with optical attenuation coefficient,9 identifying of oral squamous cell carcinoma based on texture features and machine learning classifiers,10 characterizing the optical properties of cardiovascular tissues11 and compensating the dispersion of oil based on the refractive index model in OCT via deconvolution12). Overall, they present not only OCT systems, imaging processing techniques and OCTA technology, but also their applications. Therefore, we strongly recommend this OCT issue.
