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Optical Coherence Tomography
Published in Margarida M. Barroso, Xavier Intes, In Vivo, 2020
Roshan Dsouza, Stephen A. Boppart
Over the past 25 years, OCT has emerged as a powerful imaging technology that provides unique capabilities for biomedical research. Its wide range of applications, ranging from biological to medical to industrial, indicates the breadth of impact and the success of the OCT technology. The feasibility of utilizing OCT for the evaluation and characterization of the salient features of a normal and a diseased condition can be extensively explored using suitable animal models. This allows for the use of techniques and simulations that are not directly feasible for human subjects. Preclinical studies, therefore, enable an investigator to follow a process to its natural endpoint with frequent sampling throughout the course of investigation, beyond in vitro studies. Animal models play a critically important role and enable the application of imaging techniques such as OCT to be translated into clinical human studies. The versatility of OCT has enabled its use for imaging across many different size scales, from cells, to tissues, to small animals, and to humans. OCT will continue to facilitate both biological discovery as well as clinical application.
Tissue Spectroscopy
Published in Vadim Backman, Adam Wax, Hao F. Zhang, A Laboratory Manual in Biophotonics, 2018
Vadim Backman, Adam Wax, Hao F. Zhang
Optical coherence tomography has been developed as an important 3-D imaging technique with micron-level resolutions, analogous to that from histological imaging [18]. Its noninvasive nature promises that OCT will be an excellent platform for in vivo applications in clinics, spanning ophthalmology, cardiology, dermatology, gastroenterology, and oncology. In addition to providing a morphological image in 3-D, tissue optical properties can be also quantified using OCT. The backscattering coefficient μb has been used to quantify by the amplitude of the OCT image intensity, while the scattering coefficient μs can be calculated by Beer–Lambert's law from the image intensity decay rate along the penetration depth [19,20]. However, due to the backscattering scheme of the detection, it has been a great challenge to quantify higher-order optical properties such as the anisotropic factor g in conventional OCT.
Artificial neural network (ANN) for dispersion compensation of spectral domain – optical coherence tomography (SD-OCT)
Published in Instrumentation Science & Technology, 2022
Dan Yang, Wenxin Guo, Tonglei Cheng, Zhulin Wei, Bin Xu
Optical coherence tomography (OCT) is an imaging technique that uses low-coherence light to achieve micrometer-resolution of two- and three-dimensional images through the optical scattering media (e.g., biological tissue).[1,2] In OCT, the broad-bandwidth light source is split into a sample beam (incorporating the item of interest) and a reference beam (generally a mirror). The interference pattern is produced by the combination of the reflected light of the sample beam and the reference light of the reference beam.[3] Because of its noninvasive and non-contact characteristics,[4] OCT has been clinically used in ophthalmology,[5] cardiology,[6] endoscopy,[7] dermatology,[8] and oncology.[9] Initially, OCT depth scans were performed via scanning the reference beam of the Michelson interferometer, which called time-domain OCT (TD-OCT). Today, compared with the time domain methods, the development of spectral-domain OCT (SD-OCT) enables increased imaging speed and sensitivity. For both TD-OCT and SD-OCT, OCT images are more sensitive to dispersion. The influence of the different optical path lengths in reference and sample beams for different wavelengths causes dispersion mismatch, which enlarges the axial point spread function (PSF) and causes a loss of resolution. Therefore, the cancelation of the dispersion mismatch for high quality images is a significant issue for OCT development.
Appropriate identification of age-related macular degeneration using OCT images
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2021
Marwa Hani, Amine Ben Slama, Imen Zghal, Hedi Trabelsi
Actually, the OCT software detects the internal and external boundaries of the retina and measures the total retinal thickness on the OCT scan without providing quantitative measures about pathologic features such as retinal degeneration size. As the number and size of the hyper-reflective zone reveal the advancement and severity of the pathologies, retinal regions detection can aid in diagnosis and treatments analysis (Rush et al. 2014). With such quantification, the OCT will improve patients monitoring, permit earlier detection of pathology and its accurate treatment.
A deep separable neural network for human tissue identification in three-dimensional optical coherence tomography images
Published in IISE Transactions on Healthcare Systems Engineering, 2019
Haifeng Wang, Daehan Won, Sang Won Yoon
OCT is a powerful modality used to investigate various aspects of biological characteristics such as structural information, blood flow, elastic parameters, change of polarization states, and molecular content. OCT scanning can construct 3D image data and produce a concise summary of the samples. The 3D images can create examinations that are faster and easier to read; facilitate diagnoses, treatment, and surgical planning; and increase clinical productivity. Initially, OCT was used for retinal examination in ophthalmology because of its noninvasiveness and swift diagnostic procedure (Mirza, Johnson, and Jampol, 2007). Along with the technical evolution in medical devices, the performances (e.g., output resolution, speed of processing, and projection rate) of the OCT are improving, and OCT image-based diagnoses are gaining great popularity in different medical disciplines. Numerous studies have shown the capability of OCT technology for different disease diagnoses, such as urological organ malignant microscopic structures identification (D’Amico, Weinstein, Li, Richie, and Fujimoto, 2000), breast cancer (Boppart, Luo, Marks, and Singletary, 2004), retinal pathologies examination (Mirza et al., 2007), identification and quantification of human airway wall layers (d’Hooghe et al., 2017), OCT-guided ophthalmic surgery (Ehlers et al., 2014), cervical intraepithelial neoplasia diagnosis (Gallwas et al., 2011), and thyroid tissue detection (Sommerey et al., 2015; Zhou et al., 2010) in recent years. Table 1 offers a brief overview of the OCT imaging feasibility studies in different medical disciplines. As a key insight from Table 1, OCT technology has been applied for surgery image-guidance in many medical disciplines because of its real-time, noninvasive, high imaging speed, and intraoperative imaging features.