Application Of Optical Coherence Tomography Research Articles

Research frontiers and hotspots in optical coherence tomography applications among patients with acute coronary syndromes: Bibliometric and visual analysis.

Research on the use of optical coherence tomography (OCT) in acute coronary syndrome (ACS) has increased in recent years. However, a comprehensive analysis of the trends and hotspots in OCT research is currently lacking. The objective of this study was to identify global trends in research on OCT in ACS from a bibliometric perspective and to provide researchers with new research hotspots. Relevant literature from 1998 to 2023 was retrieved from the Web of Science Core Collection. CiteSpace and VOSviewer software were used to collect and analyze publication trends in related fields. A total of 965 publications from 58 countries and 1389 institutions were included in the present study. We found that Japan produced the most publications (20.83%, 201), followed by the United States (19.90%, 192), and China (14.09%, 136). However, the United States has the highest total number of citations in this field. Harvard Medical School and Harbin Medical University had the highest numbers of publications and citations. The journal with the most publications was the International Journal of Cardiology. Plaque erosion, calcified nodules, and intracoronary imaging are the most recent research hotspots and frontiers. Our work summarizes 25 years of OCT research in the ACS, highlighting hotspots, key themes, and emerging frontiers to help guide future research.

Application of optical coherence tomography in neurodegenerative diseases: a focus on Parkinson’s, Alzheimer’s, and Schizophrenia in Bulgarian patients

This study investigates retinal alterations in patients with Alzheimer’s disease (AD), Parkinson’s disease (PD), and schizophrenia (SZ) using Optical Coherence Tomography (OCT). The primary objective was to determine whether these neurodegenerative diseases manifest in measurable retinal changes and to assess the impact of disease duration, medication use, and cognitive decline on these alterations. A cross-sectional observational design was employed, including 132 patients and age- and gender-matched controls. OCT imaging was performed using the Topcon 3D OCT-1 Maestro 2, focusing on the retinal nerve fibre layer (RNFL), ganglion cell complex (GCC), and macular thickness. Significant retinal thinning was observed in the AD and PD groups, correlating with disease severity and cognitive decline, and was more pronounced with longer disease duration. In contrast, no significant retinal changes were identified in the SZ group. The study also explored the effects of different drug classes, revealing correlations between specific medications and retinal parameters, particularly in the AD and PD cohorts. To our knowledge, this is the first study of its kind conducted with Bulgarian patients. These findings suggest that OCT may serve as a non-invasive biomarker for neurodegeneration in AD and PD, though its utility in SZ remains limited. Future research should aim to standardize OCT protocols, further investigate the potential of retinal imaging in tracking neurodegenerative disease progression, and explore its integration with other neuroimaging techniques for a more comprehensive diagnostic and monitoring approach.

In-line porosity and hardness monitoring of tablets by means of optical coherence tomography

In-line monitoring of critical quality attributes (CQAs) during a tableting process is an essential step toward a real-time release strategy. Such CQAs can be the tablet mass, the API content, dissolution, hardness and tensile strength. Since dissolution testing is laborious and time-consuming and cannot be performed in-line, it is desirable to replace dissolution testing with predictive models based on other CQAs that affect the dissolution characteristics, such as the tablet porosity and hardness. Traditionally, porosity is determined offline via gas adsorption methods or other techniques, such as Terahertz spectroscopy or gas in scattering media absorption spectroscopy. Tablet hardness is typically established using a hardness tester. While these destructive tests can readily be performed at-line, they have limited applicability in in-line settings for a high-percentage inspection. Optical coherence tomography (OCT) has recently been proposed as a possible tool for determining quality attributes. This work describes the first application of OCT for the prediction of tablet porosity and hardness. OCT measurements of tablets produced in a ConsiGma 25™ tableting line and a Stylcam 200R compaction simulator in several compaction force settings were performed and correlated with the porosity and hardness. It was demonstrated that OCT can easily be installed in-line and provide real-time information about critical material attributes. These insights confirm the applicability of OCT as a real-time quality control tool and its potential to replace time-consuming and destructive offline measurements.

All-fiber coherent supercontinuum generation in a cascade of silica, fluoride, and chalcogenide fibers

Abstract We present an all-fiber coherent supercontinuum spanning the spectral range of 1.7–5.0 µm from a cascade of silica, ZBLAN, and chalcogenide (ChG) nonlinear fibers (NLFs). Coherence is maintained by the combined use of femtosecond pump pulses as well as by allowing deterministic spectral broadening mechanism at every stage of the cascade. The use of femtosecond pump pulses enables avoiding modulation instability (MI) at the onset of the supercontinuum generation process and thus prevent subsequent MI-seeded random noise. Once in the NLF cascade, the pump pulse is instead converted into a soliton of order maintained at N < 6 in the silica and ZBLAN NLFs, ensuring soliton fission followed by self-frequency shift of a few solitons. Finally, in the ChG NLF, spectral broadening is facilitated through self-phase modulation and dispersive wave generation. The deterministic nature of these nonlinear phenomena results in the generation of a coherent supercontinuum. The supercontinuum delivers an average power of 54 mW from an average pump power of 300 mW, yielding a power conversion efficiency of 18%. The experimental results closely align with numerical simulations, from which coherence is estimated. Such a coherent supercontinuum with a megahertz repetition rate is essential for spectroscopic systems based on optical frequency combs and applications in high-precision optical coherence tomography.

Rapid differentiation of MOGAD and MS after a single optic neuritis.

Optic neuritis (ON) is a common manifestation of multiple sclerosis (MS) and myelin-oligodendrocyte-glycoprotein IgG-associated disease (MOGAD). This study evaluated the applicability of optical coherence tomography (OCT) for differentiating between both diseases in two independent cohorts. One hundred sixty two patients from seven sites underwent standard OCT and high-contrast visual acuity (HCVA) testing at least 6months after first ON. Of these, 100 patients (32 MOGAD, 68 MS) comprised the primary investigational cohort, while 62 patients (31 MOGAD, 31 MS) formed a validation cohort. A composite score distinguishing between MOGAD and MS was developed using multivariate logistic regression. Bilateral simultaneous ON occurred more frequently in MOGAD compared to MS (46.9 vs. 11.8%, p < 0.001). OCT revealed more peripapillary retinal nerve fiber layer (pRNFL) atrophy in all segments in MOGADcompared to predominantly temporal pRNFL atrophy in MS (p < 0.001). HCVA was better preserved in MS (p = 0.007). pRNFL thickness in all except for temporal segments was suitable for differentiating MOGAD and MS. Simultaneous bilateral ON and critical atrophy in nasal (< 58.5µm) and temporal superior (< 105.5µm) segments were included into the composite score as three independent predictors for MOGAD. The composite score distinguished MOGAD from MS with 75% sensitivity and 90% specificity in the investigational cohort, and 68% sensitivity and 87% specificity in the validation cohort. Following a single ON-episode, MOGAD exhibits more pronounced global pRNFL atrophy and lower visual acuity after ON compared to MS. The introduced OCT-based composite score enabled differentiation between the two entities across both cohorts.

A Review of Radiology and Optical Coherence Tomography in Dental Diagnostics

Background: The rapid evolution of imaging technologies has significantly transformed dentistry, improving the diagnosis and treatment of various dental conditions. While traditional radiological methods such as X-rays and Cone Beam Computed Tomography (CBCT) remain the cornerstone of dental imaging, the emergence of Optical Coherence Tomography (OCT) offers a non-invasive, radiation-free alternative. This review examines the comparative efficacy of X-ray and OCT technologies in diagnosing hard tissue conditions in the oral cavity. Methods: The review analyzed the application of OCT and radiology in dental diagnostics through a custom-built Swept-Source OCT system, assessing its performance against traditional radiological methods. The study utilized both in vivo and ex vivo evaluations, considering variables such as resolution, depth penetration, and image clarity across different dental conditions. Results: OCT demonstrated superior capabilities in detecting early-stage cavities, fractures, and minor imperfections, particularly when high-resolution imaging was required. However, its limited penetration compared to X-rays restricted its application in comprehensive bone assessments. Radiology, especially CBCT, provided essential volumetric data crucial for evaluating bone density, fractures, and post-surgical conditions, though it posed concerns related to radiation exposure. Combining both modalities proved beneficial, offering complementary insights that enhanced overall diagnostic accuracy. Conclusion: While X-ray-based radiology remains indispensable for broad evaluations of dental and bone structures, OCT presents a valuable adjunct, particularly for high-precision assessments of soft tissues and small surface defects. The synergistic use of these technologies can provide a more holistic approach to dental diagnostics, potentially improving patient care and treatment outcomes. Future advancements in OCT could further expand its role in routine dental practice, enhancing diagnostic accuracy while minimizing radiation exposure risks.

Line-Field Confocal Optical Coherence Tomography: A New Skin Imaging Technique Reproducing a "Virtual Biopsy" with Evolving Clinical Applications in Dermatology.

Line-field confocal optical coherence tomography is a novel technology able to reproduce a "virtual biopsy" of the skin. The aim of this review is to explore the application of line-field confocal optical coherence tomography (LC-OCT) in various skin diseases, covering skin cancers, inflammatory and infectious skin diseases, genetic diseases, cosmetic procedures, and less common disorders. Study selection was conducted based on LC-OCT and using pertinent MeSh terms, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines from inception to March 2024; to evaluate the quality and risk of bias of studies, Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used. the search retrieved 154 papers according to the selection criteria; after removing publications by one or more of the exclusion criteria, a total of 96 studies were found to be suitable for the analysis. Increasing evidence supports the use of LC-OCT as an adjunctive diagnostic tool for the in vivo diagnosis of a variety of skin tumors. As this device can be considered a "bridge" between dermoscopy and histopathology, widening applications in numerous fields of clinical dermatology, including inflammatory skin disease treatment, presurgical mapping, cosmetic procedures, and monitoring of non-invasive therapies, have been explored.

Applying optical coherence tomography to inline quality monitoring of unidirectional glass-fiber-reinforced thermoplastic tapes

Originally developed for biomedical applications and diagnosis, optical coherence tomography (OCT) has recently been demonstrated to be a powerful non-destructive and non-invasive measurement method for detecting defects in glass-fiber reinforced polymer composites. While previous studies have focused mainly on the use of OCT in the analysis of thermoset composites, we were able to show in offline experiments that OCT can be used to quickly detect typical defects (e.g., dry fiber regions, gaps and fiber breakage) in thermoplastic unidirectional (UD) tapes at high resolution. To investigate the applicability of OCT to inline monitoring, we advanced our previously published approach in two major steps: First, we incorporated the OCT system into an industrial-scale UD-tape production line, and derived optimal settings for inline detection of dry region defects from a comprehensive design of experiments (DoE) to find an optimal balance between accuracy and data size for a stationary tape sample by varying A-scan sampling rate, A-scan averaging and OCT transverse travel velocity. Second, using these optimal settings, we went on to investigate moving tapes over a range of industrially relevant take-off speeds. Microscopy was used for validation in both cases. We developed a fast and robust statistical analysis of B-scans that visualizes the quality of full cross-sections in an interpretable manner for potential use in a real-time setting. Within an industrially relevant production speed range of up to 15 m/min, we are thus now able to investigate 120 mm wide (and potentially wider) UD tapes inline at a transverse resolution of 22 µm, producing only 21 MB of data per measurement.

Optical coherence tomography and its recent applications for three-dimensional imaging of organoids

An organoid is a self-organizing, miniaturized model of an organ that recapitulates the architecture and physiology of the tissue of origin. With their high resemblance to the structure and function of real organs, organoids have shown enormous potential for studying organ development and growth, as well as modeling diseases in vitro. In organoid studies, optical coherence tomography (OCT), a coherence-based imaging technology, has garnered significant attention as an emerging tool for 3-dimensional organoid imaging. This modality enables the direct observation and monitoring of organoid structure and intercellular events at micrometer-scale resolution and millimeter-scale imaging depth, encompassing the entire body of the organoid. In this paper, we introduce the applications of OCT to recent organoid research, outlining several studies on OCT for the structural and functional imaging of different types of organoids. This review aims to inform bioengineers involved in biomedicine about OCT technologies that could be beneficial for their organoid research.

Ge-Se-Te based penrose photonic quasi-crystal fiber for SCG covering 2–21 μm MIR regime

This work proposes a Penrose-based photonic quasi-crystal fiber (PQF) composed of Arsenic-free, non-toxic chalcogenide glass for Supercontinuum (SC) generation consisting of quasi-crystal lattice of air holes having eight-fold rotational symmetry. Following optimizing the structural parameters, the proposed PQF offers zero dispersion wavelength (ZDW) at around 3.8 μm, an effective mode area of 30 μm2, and a respective high nonlinearity of 824 W−1Km−1 at 2 μm wavelength. By injecting a secant hyperbolic optical pulse having a central wavelength of 4 μm with 20 kW peak power and pulse width of 50 fs, a broadband SC of 2–21 μm is generated, which mostly covers the transparency range of the proposed material as well as Mid-IR regime. To the best of our understanding, this particular type of PQF for broadband SC generation has been proposed for the first time, serving as the novelty factor. Apart from novelty, the wide-band SC assists the proposed PQF in becoming a better counterpart for applications like optical coherence tomography (OCT), frequency metrology, and other Mid-IR applications.

Broadband and fabrication-tolerant 3-dB couplers with topological valley edge modes

3-dB couplers, which are commonly used in photonic integrated circuits for on-chip information processing, precision measurement, and quantum computing, face challenges in achieving robust performance due to their limited 3-dB bandwidths and sensitivity to fabrication errors. To address this, we introduce topological physics to nanophotonics, developing a framework for topological 3-dB couplers. These couplers exhibit broad working wavelength range and robustness against fabrication dimensional errors. By leveraging valley-Hall topology and mirror symmetry, the photonic-crystal-slab couplers achieve ideal 3-dB splitting characterized by a wavelength-insensitive scattering matrix. Tolerance analysis confirms the superiority on broad bandwidth of 48 nm and robust splitting against dimensional errors of 20 nm. We further propose a topological interferometer for on-chip distance measurement, which also exhibits robustness against dimensional errors. This extension of topological principles to the fields of interferometers, may open up new possibilities for constructing robust wavelength division multiplexing, temperature-drift-insensitive sensing, and optical coherence tomography applications.

Application of optical coherence tomography in cardiovascular diseases: bibliometric and meta-analysis.

Since the advent of Optical Coherence Tomography (OCT) two decades ago, there has been substantial advancement in our understanding of intravascular biology. Identifying culprit lesion pathology through OCT could precipitate a paradigm shift in the treatment of patients with Acute Coronary Syndrome. Given the technical prowess of OCT in the realm of cardiology, bibliometric analysis can reveal trends and research focal points in the application of OCT for cardiovascular diseases. Concurrently, meta-analyses provide a more comprehensive evidentiary base, supporting the clinical efficacy of OCT-guided Percutaneous Coronary Intervention (PCI). This study employs a dual approach of Bibliometric and Meta-analysis. Relevant literature from 2003 to 2023 was extracted from the Web of Science Core Collection (WoSCC) and analyzed using VOSviewer, CiteSpace, and R for publication patterns, countries, institutions, authors, and research hotspots. The study compares OCT-guided and coronary angiography-guided PCI in treating adult coronary artery disease through randomized controlled trials (RCTs) and observational studies. The study has been reported in the line with PRISMA and AMSTAR Guidelines. Adhering to inclusion and exclusion criteria, 310 publications were incorporated, demonstrating a continual rise in annual output. Chinese researchers contributed the most studies, while American research wielded greater influence. Analysis of trends indicated that research on OCT and angiography-guided PCI has become a focal topic in recent cohort studies and RCTs. In 11 RCTs (n = 5,277), OCT-guided PCI was not significantly associated with a reduction in the risk of Major Adverse Cardiac Events (MACE) (Odds ratio 0.84, 95% CI 0.65-1.10), cardiac death (0.61, 0.36-1.02), all-cause death (0.7, 0.49-1.02), myocardial infarction (MI) (0.88, 0.69-1.13), target lesion revascularization (TLR) (0.94, 0.7-1.27), target vessel revascularization (TVR) (1.04, 0.76-1.43), or stent thrombosis (0.72, 0.38-1.38). However, in 7 observational studies (n = 4,514), OCT-guided PCI was associated with a reduced risk of MACE (0.66, 0.48-0.91) and TLR (0.39, 0.22-0.68). Our comprehensive review of OCT in cardiovascular disease literature from 2004 to 2023, encompassing country and institutional origins, authors, and publishing journals, suggests that OCT-guided PCI does not demonstrate significant clinical benefits in RCTs. Nevertheless, pooled results from observational studies indicate a reduction in MACE and TLR.

Clinical Applications of Handheld Middle Ear Optical Coherence Tomography (ME-OCT) With Live Volumetric Visualization: Clinical Applications of 4D ME-OCT.

Clinical Applications of Handheld Middle Ear Optical Coherence Tomography (ME-OCT) With Live Volumetric Visualization: Clinical Applications of 4D ME-OCT.

Three-Dimension Epithelial Segmentation in Optical Coherence Tomography of the Oral Cavity Using Deep Learning.

This paper aims to simplify the application of optical coherence tomography (OCT) for the examination of subsurface morphology in the oral cavity and reduce barriers towards the adoption of OCT as a biopsy guidance device. The aim of this work was to develop automated software tools for the simplified analysis of the large volume of data collected during OCT. Imaging and corresponding histopathology were acquired in-clinic using a wide-field endoscopic OCT system. An annotated dataset (n = 294 images) from 60 patients (34 male and 26 female) was assembled to train four unique neural networks. A deep learning pipeline was built using convolutional and modified u-net models to detect the imaging field of view (network 1), detect artifacts (network 2), identify the tissue surface (network 3), and identify the presence and location of the epithelial-stromal boundary (network 4). The area under the curve of the image and artifact detection networks was 1.00 and 0.94, respectively. The Dice similarity score for the surface and epithelial-stromal boundary segmentation networks was 0.98 and 0.83, respectively. Deep learning (DL) techniques can identify the location and variations in the epithelial surface and epithelial-stromal boundary in OCT images of the oral mucosa. Segmentation results can be synthesized into accessible en face maps to allow easier visualization of changes.

In silico intravascular optical coherence tomography (IVOCT) for quality assured imaging with reduced intervention

In the clinical application of intravascular optical coherence tomography (IVOCT), it is necessary to flush opaque blood during image acquisition. However, there are no specific standards for how to perform low-dose but effective flushing. In this study, computational fluid dynamics (CFD) and optical models were integrated to numerically simulate the complete process of IVOCT, which includes blood flushing with normal saline followed by image acquisition. Moreover, an intermittent injection scheme was proposed, and its advantages over the conventionally adopted scheme of continuous injection were verified. The results show that intermittent injection can significantly reduce the dosage of normal saline (reduced by 44.4%) with only a slight sacrifice of image quality (reduced by 8.7%, but still acceptable). The developed model and key findings in this work can help surgeons practice optimized IVOCT operations and potentially lead to improved designs of the IVOCT equipment.

Mid-infrared optical coherence tomography with a stabilized OP-GaP optical parametric oscillator.

We demonstrate mid-infrared time-domain optical coherence tomography (OCT) with an orientation-patterned GaP optical parametric oscillator. Instantaneous broadband mid-infrared spectra provide reduced scattering for OCT applications including cultural heritage, quality assurance, and security. B-scan calibrations performed across the wavelength tuning range show depth resolutions of 67 µm at 5.1 µm and 88 µm at 10.5 µm. Volumetric imaging inside a plastic bank card is demonstrated at 5.1 µm, with a 1 Hz A-scan rate that indicates the potential of stable broadband OPO sources to contribute to mid-infrared OCT.

Quantification of attenuation and speckle features from endoscopic OCT images for the diagnosis of human brain glioma

Application of optical coherence tomography (OCT) in neurosurgery mostly includes the discrimination between intact and malignant tissues aimed at the detection of brain tumor margins. For particular tissue types, the existing approaches demonstrate low performance, which stimulates the further research for their improvement. The analysis of speckle patterns of brain OCT images is proposed to be taken into account for the discrimination between human brain glioma tissue and intact cortex and white matter. The speckle properties provide additional information of tissue structure, which could help to increase the efficiency of tissue differentiation. The wavelet analysis of OCT speckle patterns was applied to extract the power of local brightness fluctuations in speckle and its standard deviation. The speckle properties are analysed together with attenuation ones using a set of ex vivo brain tissue samples, including glioma of different grades. Various combinations of these features are considered to perform linear discriminant analysis for tissue differentiation. The results reveal that it is reasonable to include the local brightness fluctuations at first two wavelet decomposition levels in the analysis of OCT brain images aimed at neurosurgical diagnosis.

Assessment of the effects of 2,4-D-dichlorophenoxyacetic acid-based herbicide exposure in eggs and embryos of golden apple snails using OCT

This study aimed to evaluate the effects of herbicide 2, 4-D-dichlorophenoxy acetic acid on golden apple snail eggs and embryos. Additionally, the study assessed the applicability of optical coherence tomography (OCT), a non-invasive depth cross-sectional microscopic imaging technique, as a novel method, to the best of our knowledge, for studying morphological changes in golden apple snail eggs and embryos, in comparison to the conventional approach of using white light microscopy. The study revealed that the herbicide 2,4-D-dichlorophenoxy acetic acid affected the hatchery rate and morphological changes of the eggs and embryos. The lethal concentration (LC50), representing the concentration of a substance that is expected to cause death in half of the population being studied, of the golden apple eggs and embryos increased with longer exposure time and higher concentrations. The estimated median effective concentration (EC50), which denotes the concentration producing the desired effect in 50% of the exposed golden apple embryos, exhibited a similar trend of change as the LC50. When compared to the microscopic study, it was observed that OCT could be employed to investigate morphological changes of golden apple snail eggs and embryos, enabling evaluation of alterations in both 2D and 3D structures.

Skin Imaging Using Optical Coherence Tomography and Photoacoustic Imaging: A Mini-Review

This article provides an overview of the progress made in skin imaging using two emerging imaging modalities, optical coherence tomography (OCT) and photoacoustic imaging (PAI). Over recent years, these technologies have significantly advanced our understanding of skin structure and function, offering non-invasive and high-resolution insights previously unattainable. The review begins by briefly describing the fundamental principles of how OCT and PAI capture images. It then explores the evolving applications of OCT in dermatology, ranging from diagnosing skin disorders to monitoring treatment responses. This article continues by briefly describing the capabilities of PAI imaging, and how PAI has been used for melanoma and non-melanoma skin cancer detection and characterization, vascular imaging, and more. The third section describes the development of multimodal skin imaging systems that include OCT, PAI, or both modes. A comparative analysis between OCT and PAI is presented, elucidating their respective strengths, limitations, and synergies in the context of skin imaging.

Clinical application and development of OCT and OCTA in fundus diseases

Optical coherence tomography (OCT), which uses light wave as the imaging method, is a new medical imaging technology based on optical coherence. Optical coherence tomography angiography (OCTA) is a non-invasive imaging method gradually emerging in recent years. This technique can detect flowing blood and evaluate tissue morphology by detecting normal flow of red blood cells in blood vessels. Because of the advantages of high resolution, easy operation and three-dimensional imaging, it is widely used in the diagnosis and evaluation of fundus diseases (such as diabetic retinopathy, choroidal neovascularization, retinal vein occlusion, etc.). This article reviews the application status and progress of OCT and OCTA in clinical diagnosis and treatment of fundus diseases.