Journal articles: 'Directional optical coherence tomography'

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Wartak, Andreas, Marco Augustin, Richard Haindl, Florian Beer, Matthias Salas, Marie Laslandes, Bernhard Baumann, Michael Pircher, and Christoph K. Hitzenberger. "Multi-directional optical coherence tomography for retinal imaging." Biomedical Optics Express 8, no. 12 (November 13, 2017): 5560. http://dx.doi.org/10.1364/boe.8.005560.

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Tong, Kevin K., Brandon J. Lujan, Yixiu Zhou, and Meng C. Lin. "Directional Optical Coherence Tomography Reveals Reliable Outer Nuclear Layer Measurements." Optometry and Vision Science 93, no. 7 (July 2016): 714–19. http://dx.doi.org/10.1097/opx.0000000000000861.

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Geevarghese, Alexi, Gadi Wollstein, Hiroshi Ishikawa, and Joel S. Schuman. "Optical Coherence Tomography and Glaucoma." Annual Review of Vision Science 7, no. 1 (September 15, 2021): 693–726. http://dx.doi.org/10.1146/annurev-vision-100419-111350.

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Early detection and monitoring are critical to the diagnosis and management of glaucoma, a progressive optic neuropathy that causes irreversible blindness. Optical coherence tomography (OCT) has become a commonly utilized imaging modality that aids in the detection and monitoring of structural glaucomatous damage. Since its inception in 1991, OCT has progressed through multiple iterations, from time-domain OCT, to spectral-domain OCT, to swept-source OCT, all of which have progressively improved the resolution and speed of scans. Even newer technological advancements and OCT applications, such as adaptive optics, visible-light OCT, and OCT-angiography, have enriched the use of OCT in the evaluation of glaucoma. This article reviews current commercial and state-of-the-art OCT technologies and analytic techniques in the context of their utility for glaucoma diagnosis and management, as well as promising future directions.

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Wojtkowski, Maciej, Bartlomiej Kaluzny, and Robert J. Zawadzki. "New Directions in Ophthalmic Optical Coherence Tomography." Optometry and Vision Science 89, no. 5 (May 2012): 524–42. http://dx.doi.org/10.1097/opx.0b013e31824eecb2.

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Saleah, Sm Abu, Daewoon Seong, Sangyeob Han, Ruchire Eranga Wijesinghe, Naresh Kumar Ravichandran, Mansik Jeon, and Jeehyun Kim. "Integrated Quad-Scanner Strategy-Based Optical Coherence Tomography for the Whole-Directional Volumetric Imaging of a Sample." Sensors 21, no. 4 (February 11, 2021): 1305. http://dx.doi.org/10.3390/s21041305.

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Whole-directional scanning methodology is required to observe distinctive features of an entire physical structure with a three dimensional (3D) visualization. However, the implementation of whole-directional scanning is challenging for conventional optical coherence tomography (OCT), which scans a limited portion of the sample by utilizing unidirectional and bidirectional scanning methods. Therefore, in this paper an integrated quad-scanner (QS) strategy-based OCT method was implemented to obtain the whole-directional volumetry of a sample by employing four scanning arms installed around the sample. The simultaneous and sequential image acquisition capabilities are the conceptual key points of the proposed QS-OCT method, and were implemented using four precisely aligned scanning arms and applied in a complementary way according to the experimental criteria. To assess the feasibility of obtaining whole-directional morphological structures, a roll of Scotch tape, an ex vivo mouse heart, and kidney specimens were imaged and independently obtained tissue images at different directions were delicately merged to compose the 3D volume data set. The results revealed the potential merits of QS-OCT-based whole-directional imaging, which can be a favorable inspection method for various discoveries that require the dynamic coordinates of the whole physical structure.

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Targowski, Piotr, Michalina Góra, Tomasz Bajraszewski, Maciej Szkulmowski, Bogumiła Rouba, Teresa Łękawa-Wysłouch, and Ludmiła Tymińska-Widmer. "Optical Coherence Tomography for Tracking Canvas Deformation." Laser Chemistry 2006 (January 22, 2006): 1–8. http://dx.doi.org/10.1155/2006/93658.

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Preliminary results of the application of optical coherence tomography (OCT), in particular in its spectral mode (SOCT), to tracking of deformations in paintings on canvas caused by periodical humidity changes are presented. The setup is able to monitor the position of a chosen point at the surface of a painting with micrometre precision, simultaneously in three dimensions, every 100 seconds. This allows recording of deformations associated with crack formation. For the particular painting model examined, it was shown that the surface moves in-plane towards the corner, and bulges outwards (Z-direction) in response to a rise in humidity. Subsequent to the first humidification/drying cycle, translation in the Z-direction is decreased, whilst in-plane translations increase somewhat. It was also shown that the response of the painting on canvas begins immediately on changing the relative humidity in the surroundings.

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Grimm, Matthias, Hessam Roodaki, Abouzar Eslami, and Nassir Navab. "Automatic intraoperative optical coherence tomography positioning." International Journal of Computer Assisted Radiology and Surgery 15, no. 5 (April 2, 2020): 781–89. http://dx.doi.org/10.1007/s11548-020-02135-w.

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Abstract Purpose Intraoperative optical coherence tomography (iOCT) was recently introduced as a new modality for ophthalmic surgeries. It provides real-time cross-sectional information at a very high resolution. However, properly positioning the scan location during surgery is cumbersome and time-consuming, as a surgeon needs both his hands for surgery. The goal of the present study is to present a method to automatically position an iOCT scan on an anatomy of interest in the context of anterior segment surgeries. Methods First, a voice recognition algorithm using a context-free grammar is used to obtain the desired pose from the surgeon. Then, the limbus circle is detected in the microscope image and the iOCT scan is placed accordingly in the X–Y plane. Next, an iOCT sweep in Z direction is conducted and the scan is placed to centre the topmost structure. Finally, the position is fine-tuned using semantic segmentation and a rule-based system. Results The logic to position the scan location on various anatomies was evaluated on ex vivo porcine eyes (10 eyes for corneal apex and 7 eyes for cornea, sclera and iris). The mean euclidean distances (± standard deviation) was 76.7 (± 59.2) pixels and 0.298 (± 0.229) mm. The mean execution time (± standard deviation) in seconds for the four anatomies was 15 (± 1.2). The scans have a size of 1024 by 1024 pixels. The method was implemented on a Carl Zeiss OPMI LUMERA 700 with RESCAN 700. Conclusion The present study introduces a method to fully automatically position an iOCT scanner. Providing the possibility of changing the OCT scan location via voice commands removes the burden of manual device manipulation from surgeons. This in turn allows them to keep their focus on the surgical task at hand and therefore increase the acceptance of iOCT in the operating room.

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Meleppat, Ratheesh K., Pengfei Zhang, Myeong Jin Ju, Suman K. Manna, Yifan Jian, Edward N. Pugh, and Robert J. Zawadzki. "Directional optical coherence tomography reveals melanin concentration-dependent scattering properties of retinal pigment epithelium." Journal of Biomedical Optics 24, no. 06 (June 28, 2019): 1. http://dx.doi.org/10.1117/1.jbo.24.6.066011.

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Lujan, Brandon J., Austin Roorda, Jason A. Croskrey, Adam M. Dubis, Robert F. Cooper, Jan-Kristine Bayabo, Jacque L. Duncan, Bhavna J. Antony, and Joseph Carroll. "DIRECTIONAL OPTICAL COHERENCE TOMOGRAPHY PROVIDES ACCURATE OUTER NUCLEAR LAYER AND HENLE FIBER LAYER MEASUREMENTS." Retina 35, no. 8 (August 2015): 1511–20. http://dx.doi.org/10.1097/iae.0000000000000527.

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Dolz-Marco, Rosa, and K. Bailey Freund. "DIRECTIONAL CHANGES IN TISSUE REFLECTIVITY MAY INFLUENCE FLOW DETECTION ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY." Retina 38, no. 4 (April 2018): 739–47. http://dx.doi.org/10.1097/iae.0000000000001656.

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Oida, Daisuke, Kiriko Tomita, Kensuke Oikawa, Tai-Ang Wang, Shuichi Makita, Meng-Tsan Tsai, and Yoshiaki Yasuno. "Computational multi-directional optical coherence tomography for visualizing the microstructural directionality of the tissue." Biomedical Optics Express 12, no. 7 (June 7, 2021): 3851. http://dx.doi.org/10.1364/boe.426125.

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Pellegrini, Marco, Aldo Vagge, Lorenzo Ferro Desideri, Federico Bernabei, Giacinto Triolo, Rodolfo Mastropasqua, Chiara Del Noce, et al. "Optical Coherence Tomography Angiography in Neurodegenerative Disorders." Journal of Clinical Medicine 9, no. 6 (June 2, 2020): 1706. http://dx.doi.org/10.3390/jcm9061706.

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Retinal microcirculation shares similar features with cerebral small blood vessels. Thus, the retina may be considered an accessible ‘window’ to detect the microvascular damage occurring in the setting of neurodegenerative disorders. Optical coherence tomography angiography (OCT-A) is a non-invasive imaging modality providing depth resolved images of blood flow in the retina, choroid, and optic nerve. In this review, we summarize the current literature on the application of OCT-A in glaucoma and central nervous system conditions such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Future directions aiming at evaluating whether OCT-A can be an additional biomarker for the early diagnosis and monitoring of neurodegenerative disorders are also discussed.

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Huang, Brendan K., and Michael A. Choma. "Resolving directional ambiguity in dynamic light scattering-based transverse motion velocimetry in optical coherence tomography." Optics Letters 39, no. 3 (January 23, 2014): 521. http://dx.doi.org/10.1364/ol.39.000521.

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Lu, Yi-Ting, Benedictus Yohanes Bagus Widhianto, Shih-Hsiang Hsu, and Che-Chang Chang. "Tandem Mach Zehnder Directional Coupler Design and Simulation on Silicon Platform for Optical Coherence Tomography Applications." Sensors 20, no. 4 (February 15, 2020): 1054. http://dx.doi.org/10.3390/s20041054.

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We design and compare the splitting ratio wavelength flatness of directional coupler (DC), Mach-Zehnder directional coupler (MZDC), and tandem MZDC. All coupler responses are analyzed, and tandem MZDC performance is the best in the wavelength insensitivity compared with the other two. An MZDC with any coupling ratio could be utilized to match the maximum flatness in a 40-nm wavelength range. To extend a broad flatness range, the tandem MZDC is proposed and still follows the Mach Zehnder structure taking two MZDCs as couplers connected through a decoupled region. Unlike DC, MZDC with the flat wavelength response has a non-linear output phase. Hence, using two wavelength-insensitive MZDCs as the coupling function in a tandem MZDC could demonstrate a more extensive decoupled phase term to maximize the flat wavelength response. The tandem MZDC theoretically demonstrates the splitting ratio with 100-nm flatness in the wavelength range from 1250 nm to 1350 nm. Finally, a point spread function through the tandem MZDC shows a 24-dB signal-to-noise ratio improvement in optical coherence tomography applications.

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Kirtane, Tejas S., and Mihir S. Wagh. "Endoscopic Optical Coherence Tomography (OCT): Advances in Gastrointestinal Imaging." Gastroenterology Research and Practice 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/376367.

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In the rapidly evolving field of endoscopic gastrointestinal imaging, Optical Coherence Tomography (OCT) has found many diverse applications. We present the current status of OCT and its practical applications in imaging normal and abnormal mucosa in the esophagus, stomach, small and large intestines, and biliary and pancreatic ducts. We highlight technical aspects and principles of imaging, assess published data, and suggest future directions for OCT-guided evaluation and therapy.

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Alasil, Tarek, Pearse A. Keane, Dawn A. Sim, Adnan Tufail, and Michael E. Rauser. "Optical Coherence Tomography in Pediatric Ophthalmology: Current Roles and Future Directions." Ophthalmic Surgery, Lasers and Imaging Retina 44, no. 6 (Suppl) (November 1, 2013): S19—S29. http://dx.doi.org/10.3928/23258160-20131101-04.

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Poon, Karl KC, Alexander Incani, O. Christopher Raffel, Darren L. Walters, and Ik-Kyung Jang. "Optical coherence tomography: research applications, potential clinical utility and future directions." Interventional Cardiology 4, no. 6 (December 2012): 709–20. http://dx.doi.org/10.2217/ica.12.72.

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Ali, Ziad A., Keyvan Karimi Galougahi, Gary S. Mintz, Akiko Maehara, Richard A. Shlofmitz, and Alessio Mattesini. "Intracoronary optical coherence tomography: state of the art and future directions." EuroIntervention 17, no. 2 (June 2021): e105-e123. http://dx.doi.org/10.4244/eij-d-21-00089.

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Yao, Gang, and Dongsheng Duan. "High-resolution 3D tractography of fibrous tissue based on polarization-sensitive optical coherence tomography." Experimental Biology and Medicine 245, no. 4 (December 8, 2019): 273–81. http://dx.doi.org/10.1177/1535370219894332.

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Fibrous tissues play important roles in many parts of the body. Their highly organized directional structure is essential in achieving their normal biomechanical and physiological functions. Disruption of the typical fiber organization in these tissues is often linked to pathological changes and disease progression. Tractography is a specialized imaging method that can reveal the detailed fiber architecture. Here, we review recent developments in high-resolution optical tractography using Jones matrix polarization-sensitive optical coherence tomography. We also illustrate the use of this new tractography technology for visualizing depth-resolved, three-dimensional fibrous structures and quantifying tissue damages in several major fibrous tissues. Impact statement Organized fiber structure plays an essential role in realizing normal biological functions in fibrous tissues. A thorough understanding of the structure–function relationship in these tissues is crucial for developing effective technology to diagnose and treat diseases. Tractography imaging is an effective tool in visualizing and quantifying fiber architecture in fibrous tissues. This review describes a recently developed tractography technology that has shown great promise for fast image of 3D fiber organization with microscopic details.

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Schwindt, Arne G., J. Gray Bennett, William H. Crowder, Suhail Dohad, Sean F. Janzer, Jon C. George, Barry Tedder, et al. "Lower Extremity Revascularization Using Optical Coherence Tomography–Guided Directional Atherectomy: Final Results of the EValuatIon of the PantheriS OptIcal COherence Tomography ImagiNg Atherectomy System for Use in the Peripheral Vasculature (VISION) Study." Journal of Endovascular Therapy 24, no. 3 (April 10, 2017): 355–66. http://dx.doi.org/10.1177/1526602817701720.

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Purpose: To evaluate the safety and efficacy of a novel optical coherence tomography (OCT)–guided atherectomy catheter in treating patients with symptomatic femoropopliteal disease. Methods: The VISION trial ( ClinicalTrials.gov identifier NCT01937351) was a single-arm, multicenter, global investigational device exemption study enrolling 158 subjects (mean age 67.2±10.5 years; 87 men) across 20 participating sites. In this cohort, 198 lesions were treated with an average length of 53±40 mm using the Pantheris catheter alone or Pantheris + adjunctive therapy. The primary safety endpoint was the composite of major adverse events (MAEs) through 6 months (objective performance goal 43.2%). Technical success (primary efficacy outcome) was defined as the percent of target lesions with a residual diameter stenosis ≤50% after treatment with the Pantheris device alone (objective performance goal 87.0%). Procedural success was defined as reduction in stenosis to ≤30% after Pantheris ± adjunctive therapy. Tissue specimens retrieved from each treated lesion were histologically analyzed to evaluate the accuracy and precision of OCT image guidance. Results: The primary efficacy outcome was achieved in 192 (97.0%) of the 198 lesions treated with the Pantheris catheter. Across all lesions, mean diameter stenosis was reduced from 78.7%±15.1% at baseline to 30.3%±11.8% after Pantheris alone (p<0.001) and to 22.4%±9.9% after Pantheris ± adjunctive therapy (p<0.001). Of the 198 target lesions, 104 (52.5%) were treated with the Pantheris alone, 84 (42.4%) were treated with Pantheris + adjunctive angioplasty, and 10 (5.1%) with Pantheris + angioplasty + stenting. The composite MAE outcome through 6 months occurred in 25 (16.6%) of 151 subjects. There were no clinically significant perforations, 1 (0.5%) catheter-related dissection, 4 (2%) embolic events, and a 6.4% clinically driven target lesion revascularization rate at 6 months. The 40-lesion chronic total occlusion (CTO) subset (mean lesion length 82±38 mm) achieved a similar significant reduction in stenosis to 35.5%±13.6% after Pantheris alone (p<0.001). Histological analysis of atherectomy specimens confirmed <1% adventitia in 82.1% of the samples, highlighting the precision of OCT guidance. Characterization of the OCT-guided lesions revealed evidence of an underestimation of disease burden when using fluoroscopy. Conclusion: OCT-guided atherectomy for femoropopliteal disease is safe and effective. Additionally, the precision afforded by OCT guidance leads to greater removal of plaque during atherectomy while sparing the adventitia.

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Xie, Tuqiang, Shuguang Guo, Jun Zhang, Zhongping Chen, and George M. Peavy. "Use of polarization-sensitive optical coherence tomography to determine the directional polarization sensitivity of articular cartilage and meniscus." Journal of Biomedical Optics 11, no. 6 (2006): 064001. http://dx.doi.org/10.1117/1.2397574.

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Ibne Mokbul, Mobin. "Optical Coherence Tomography: Basic Concepts and Applications in Neuroscience Research." Journal of Medical Engineering 2017 (October 29, 2017): 1–20. http://dx.doi.org/10.1155/2017/3409327.

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Optical coherence tomography is a micrometer-scale imaging modality that permits label-free, cross-sectional imaging of biological tissue microstructure using tissue backscattering properties. After its invention in the 1990s, OCT is now being widely used in several branches of neuroscience as well as other fields of biomedical science. This review study reports an overview of OCT’s applications in several branches or subbranches of neuroscience such as neuroimaging, neurology, neurosurgery, neuropathology, and neuroembryology. This study has briefly summarized the recent applications of OCT in neuroscience research, including a comparison, and provides a discussion of the remaining challenges and opportunities in addition to future directions. The chief aim of the review study is to draw the attention of a broad neuroscience community in order to maximize the applications of OCT in other branches of neuroscience too, and the study may also serve as a benchmark for future OCT-based neuroscience research. Despite some limitations, OCT proves to be a useful imaging tool in both basic and clinical neuroscience research.

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Peng, Shizhao, Yuanzhen Jiang, Kailin Zhang, Chuanchao Wu, Danni Ai, Jian Yang, Yongtian Wang, and Yong Huang. "Cooperative Three-View Imaging Optical Coherence Tomography for Intraoperative Vascular Evaluation." Applied Sciences 8, no. 9 (September 4, 2018): 1551. http://dx.doi.org/10.3390/app8091551.

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Real-time intraoperative optical coherence tomography (OCT) imaging of blood vessels after anastomosis operation can provide important information the vessel, such as patency, flow speed, and thrombosis morphology. Due to the strong scattering and absorption effect of blood, normal OCT imaging suffers from the problem of incomplete cross-sectional view of the vessel under investigation when the diameter is large. In this work, we present a novel cooperative three-view imaging spectral domain optical coherence tomography system for intraoperative exposed vascular imaging. Two more side views (left view and right view) were realized through a customized sample arm optical design and corresponding mechanical design and fabrication, which could generate cross-sectional images from three circumferential view directions to achieve a larger synthetic field of view (FOV). For each view, the imaging depth was 6.7 mm (in air) and the lateral scanning range was designed to be 3 mm. Therefore, a shared synthetic rectangle FOV of 3 mm × 3 mm was achieved through cooperative three view scanning. This multi-view imaging method can meet the circumferential imaging demands of vessels with an outer diameter less than 3 mm. Both phantom tube and rat vessel imaging confirmed the increased system FOV performance. We believe the intraoperative application of this cooperative three-imaging optical coherence tomography for objective vascular anastomosis evaluation can benefit patient outcomes in the future.

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Kim, Ji Bak, Hyeong Soo Nam, Hongki Yoo, and Jin Won Kim. "A bi-directional assessment of spontaneous coronary artery dissection by three-dimensional flythrough rendering of optical coherence tomography images." European Heart Journal 36, no. 17 (January 2, 2015): 1022. http://dx.doi.org/10.1093/eurheartj/ehu498.

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Cho, Nam Hyun, and Jeong Hun Jang. "Future Directions of Optical Coherence Tomography in Otology: A Morphological and Functional Approach." Clinical and Experimental Otorhinolaryngology 13, no. 2 (May 1, 2020): 85–86. http://dx.doi.org/10.21053/ceo.2020.00031.

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CHEN, XIAODONG, QIAO LI, YONG LEI, YI WANG, and DAOYIN YU. "SDOCT IMAGE RECONSTRUCTION BY INTERFEROMETRIC SYNTHETIC APERTURE MICROSCOPY." Journal of Innovative Optical Health Sciences 03, no. 01 (January 2010): 17–23. http://dx.doi.org/10.1142/s1793545810000812.

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Spectral domain optical coherence tomography (SDOCT) is a noninvasive, cross-sectional imaging technique that measures depth resolved reflectance of tissue by Fourier transforming the spectral interferogram with the scanning of the reference avoided. Interferometric synthetic aperture microscopy (ISAM) is an optical microscopy computed-imaging technique for measuring the optical properties of biological tissues, which can overcome the compromise between depth of focus and transverse resolution. This paper describes the principle of SDOCT and ISAM, which multiplexes raw acquisitions to provide quantitatively meaningful data with reliable spatially invariant resolution at all depths. A mathematical model for a coherent microscope with a planar scanning geometry and spectral detection was described. The two-dimensional fast Fourier transform (FFT) of spectral data in the transverse directions was calculated. Then the nonuniform ISAM resampling and filtering was implemented to yield the scattering potential within the scalar model. Inverse FFT was used to obtain the ISAM reconstruction. One scatterer, multiple scatterers, and noisy simulations were implemented by use of ISAM to catch spatially invariant resolution. ISAM images were compared to those obtained using standard optical coherence tomography (OCT) methods. The high quality of the results validates the rationality of the founded model and that diffraction limited resolution can be achieved outside the focal plane.

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Habara, Maoto, Fumiyuki Otsuka, Etsuo Tsuchikane, Mitsuyasu Terashima, Kenya Nasu, Yoshihisa Kinoshita, Akira Murata, et al. "In vivo tissue characterization of human atherosclerotic plaques by optical coherence tomography: A directional coronary atherectomy study with histopathologic confirmation." International Journal of Cardiology 268 (October 2018): 1–10. http://dx.doi.org/10.1016/j.ijcard.2018.05.022.

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Dong, Yue, Jinye Yang, Yin Xu, Bo Zhang, and Yi Ni. "On-Chip Beam Splitting Strategies Based on SWG Assisted Directional Coupler for 850 nm Optical Coherence Tomography - A Numerical Study." IEEE Photonics Journal 13, no. 2 (April 2021): 1–12. http://dx.doi.org/10.1109/jphot.2021.3058800.

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WANG, ZHENGUO, CHRISTOPHER S. D. LEE, WAYNE C. WALTZER, ZHIJIA YUAN, and YINGTIAN PAN. "INTERPIXEL-SHIFTED ENDOSCOPIC OPTICAL COHERENCE TOMOGRAPHY FOR IN VIVO BLADDER CANCER DIAGNOSIS." International Journal of Image and Graphics 07, no. 01 (January 2007): 105–17. http://dx.doi.org/10.1142/s021946780700257x.

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An interpixel-shifted spectral imaging technique is applied to MEMS-based spectral-domain endoscopic optical coherence tomography (SDEOCT) to enhance signal-to-noise ratio and effective imaging depth for in vivo imaging diagnosis of biological tissue. To validate the enhancements of pixel-shifted SDEOCT, experimental comparisons are presented to image animal and human bladder architectures in vivo and to diagnose human transitional cell cancers. Preliminary study shows that interpixel shifted SDEOCT not only increases the depth of field of SDOCT but also eliminates excessive artifacts induced by spectral aliasing effect, thus improving image contrast in areas with large depths (e.g. over 1.5 mm). These results suggest that endoscopic OCT equipped with interpixel-shifted spectral camera has the potential to enhance the diagnosis of biological tissue in in vivo settings that require a larger field of view in the axial direction, such as papillary bladder tumors with deep surface irregularities (e.g. asperities or invaginations).

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Falavarjani, Khalil Ghasemi, and David Sarraf. "Optical coherence tomography angiography of the retina and choroid; current applications and future directions." Journal of Current Ophthalmology 29, no. 1 (March 2017): 1–4. http://dx.doi.org/10.1016/j.joco.2017.02.005.

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Yang, Xiao-Long, Bao-Gen Luo, Yue Xu, and Xiao-Feng Zhang. "Corneal epithelial thickness analysis of forme fruste keratoconus with optical coherence tomography." International Journal of Ophthalmology 14, no. 1 (January 18, 2021): 89–96. http://dx.doi.org/10.18240/ijo.2021.01.13.

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AIM: To explore the significance of corneal epithelial thickness analysis in diagnosing early keratoconus. METHODS: There were 26 clinical keratoconus, 21 forme fruste keratoconus, 40 high corneal astigmatism (ΔK) and 40 low ΔK eyes involved in the study. Fourier-domain optical coherence tomography was used to measure the corneal epithelial thickness of four groups. The morphological features of topographic map and the thickness of corneal epithelial thinnest point were analyzed. The distribution curve of corneal epithelial thickness at 45°, 90°, and 135° axial directions that are through the pupil center was also analyzed. One-way ANOVA was performed to compare the data. RESULTS: The topographic map of forme fruste keratoconus corneal epithelial thickness was uniformity shape; crater shape existed only in clinical keratoconus group; and central island shape mainly existed in high ΔK group. The thinnest point of corneal epithelial thickness of forme fruste keratoconus group was significantly lower than that of low ΔK group (P=0.022). The thickness of corneal epithelium in the forme fruste keratoconus at 90° was thinner than that in the low astigmatism group at -1, and -2 mm points (P-1 mm=0.015, P-2 mm=0.036). CONCLUSION: The analysis of the thinnest point in forme fruste keratoconus corneal epithelium appears earlier than corneal epithelial remodeling. The topographic map of corneal epithelium in high ΔK eyes appears in central island shape, and can be used for the differential diagnosis of early keratoconus.

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Chen, Yan Hua. "Progress of Intravascular Optical Coherence Tomography Image Technology and Vascular Three-Dimensional Reconstruction." Advanced Materials Research 1049-1050 (October 2014): 515–19. http://dx.doi.org/10.4028/www.scientific.net/amr.1049-1050.515.

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Intravascular optical coherence tomography (IV-OCT) is a new intervention imaging technology for the diagnosis of coronary heart disease. Because of its high-resolution and non-invasive characteristics, it is widely used in clinical medicine. It has a revolutionary impact on coronary artery disease diagnosis, prognosis and treatment decisions. This paper studied this hot topic, gave the basic concepts of intravascular OCT image sequences. In accordance with current development studies, the key technology for three-dimensional reconstruction of the coronary vascular system is proposed and analyzed. On this basis, we proposed future research directions on IV-OCT vascular three-dimensional reconstruction, including clinical trial frequency domain OCT (OFDI), the combination of IV-OCT and intravascular ultrasound (IVUS) and a preliminary study of intravascular photoacoustic (IVPA) imaging.

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Willerslev, Anne, Xiao Q. Li, Inger C. Munch, and Michael Larsen. "Flow patterns on spectral-domain optical coherence tomography reveal flow directions at retinal vessel bifurcations." Acta Ophthalmologica 92, no. 5 (July 2, 2013): 461–64. http://dx.doi.org/10.1111/aos.12233.

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Micieli, JonathanA, Cody Lo, and LaurelN Vuong. "Recent advances and future directions on the use of optical coherence tomography in neuro-ophthalmology." Taiwan Journal of Ophthalmology 11, no. 1 (2021): 3. http://dx.doi.org/10.4103/tjo.tjo_76_20.

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Usuki, Shin, Katsuaki Tamaki, and Kenjiro T. Miura. "Three-Dimensional Reconstruction by Time-Domain Optical Coherence Tomography Microscope with Improved Measurement Range." International Journal of Automation Technology 11, no. 5 (August 30, 2017): 787–94. http://dx.doi.org/10.20965/ijat.2017.p0787.

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The objective of this research was to develop a three-dimensional (3D) reconstruction system based on a time-domain optical coherence tomography (OCT) microscope. One of the critical drawbacks of OCT microscopes is that their axial measurement ranges are typically limited by their depths of field (DOFs), which are determined by the numerical apertures of their objective lenses and the central wavelengths of their light sources. If a low-coherence interference fringe is far outside the DOF, the measurement accuracy inevitably decreases, regardless of how well-adjusted the reference mirror is. To address this issue and improve the axial measurement range of the OCT microscope in this study, an object-scanning measurement scheme involving a Linnik interferometer was developed. To calibrate the system in the proposed technique, image post-processing is performed for a well-conditioned state to ensure that a low-coherence interference fringe is generated within the DOF, enabling 3D objects with high-aspect-ratio structures to be scanned along the axial direction. During object-scanning, this state is always monitored and is corrected by adjusting the reference mirror. By using this method, the axial measurement range can be improved up to the working distance (WD) of the objective lens without compromising the measurement accuracy. The WD is typically longer than 10 mm, while the DOF of the microscope is around 0.01 mm in general, although it varies depending on the imaging system. In this report, the experimental setup of a 3D reconstruction system is presented, a series of experimental verifications is described, and the results are discussed. The axial measurement range was improved to at least 35 times that of a typical OCT microscope with identical imaging optics.

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Venkataraman, Abinaya Priya, Josefine Andersson, Lina Fivelsdal, Maria Nilsson, and Alberto Domínguez-Vicent. "Impact of optical coherence tomography scan direction on the reliability of peripapillary retinal nerve fiber layer measurements." PLOS ONE 16, no. 2 (February 22, 2021): e0247670. http://dx.doi.org/10.1371/journal.pone.0247670.

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Purpose To evaluate the intradevice repeatability and agreement for peripapillary retinal nerve fiber layer (pRNFL) measurements in healthy eyes with two different scan directions and two different number of B scans. Methods pRNFL was measured with a spectral domain optical coherence tomography on 54 healthy participants. Three-dimensional optic disc scans (6 mm x 6 mm) were performed on the right eye of the participants. Two repeated scans were performed in four different settings: H1: Horizontal scan with 512 A-scans x 96 B-scans; H2: Horizontal scan with 512 A-scans x 128 B-scans; V1: Vertical scan with 512 A-scans x 96 B-scans; V2: Vertical scan with 512 A-scans x 128 B-scans. The pRNFL thickness was evaluated in twelve clock-hour sector in a circle of 3.45 mm diameter centred at the optic disc. Repeatability and agreement were assessed with within subject standard deviation (Sw) and Bland-Altman test respectively. Results The repeatability of pRNFL measurements varied depending on the scan direction and sectors. The repeatability for the horizontal sectors were better with H1 and H2, with sector 9 having the best Sw (< 3 μm). The repeatability for the vertical sectors were better with V1 and V2 with sector 5 and 9 having the best Sw (< 4 μm). The repeatability with vertical scan was more symmetric among the sectors than with horizontal scans. The repeatability metrics of the sectors did not vary much between H1 and H2 (difference < 2 μm) and between V1 and V2 (difference < 3.2 μm). Comparing horizontal and vertical scans, the vertical sectors had larger limits of agreement of about 45 μm. Conclusion The reliability of the pRNFL thickness measurements is dependent on the direction of the scan and independent on the numbers of B-scans. Vertical scans for pRNFL gives more homogeneous repeatability across the different sectors.

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Delgado-Ruiz, Rafael, Mina Mahdian, Ilyasse Benezha, and Georgios Romanos. "Counterclockwise Drilling with Different Tapered Drills Condenses the Implant Bed—An Optical Coherence Tomography In Vitro Study." Medicina 57, no. 9 (September 6, 2021): 940. http://dx.doi.org/10.3390/medicina57090940.

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Background and Objectives: To evaluate the condensation and the microarchitecture of implant bed walls of sites prepared with counterclockwise drilling with tapered implant drills using optical coherence tomography. Materials and Methods: Four drill designs with different wall and tip angles were used. Polyurethane laminas resembling type IV bone microarchitecture were superimposed and clamped with a vice to simulate the coronal, middle, and apical aspects of the implant site. Twenty implant beds were prepared at 1200 rpm in clockwise (control) and counterclockwise (test) directions (N = 160). Optical coherence tomography (OCT) was used to evaluate the condensation and microarchitecture characteristics of the implant bed walls. The relative condensation was calculated using the Image J software Bone application. The microarchitecture was evaluated in reconstructed 3D volumes in XY, XZ, and YZ sections. Statistical analysis was performed using one-way ANOVA. Dunnet test was applied to determine differences between groups. Significance was set as p < 0.05. Results: Counterclockwise drilling (Test) condensed and changed the microarchitecture of the apical regions for all the implant beds in all of the groups when compared to clockwise drilling (control). The apical region of test groups showed the highest relative bone condensation (p = 0.026) when compared to controls. Conclusions: The direction of rotation (counterclockwise drilling) and not the design of tapered drills (tip and wall angles) is responsible for the condensation at the apical area observed in polyurethane blocks. The OCT method can be used for the evaluation of changes in density and microstructure of polyurethane blocks.

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Zhang, Qinqin, Maureen Neitz, Jay Neitz, and Ruikang K. Wang. "Geographic mapping of choroidal thickness in myopic eyes using 1050-nm spectral domain optical coherence tomography." Journal of Innovative Optical Health Sciences 08, no. 04 (July 2015): 1550012. http://dx.doi.org/10.1142/s1793545815500121.

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Purpose: To provide a geographical map of choroidal thickness (CT) around the macular region among subjects with low, moderate and high myopia. Methods: 20 myopic subjects (n = 40 eyes) without other identified pathologies participated in this study: 20 eyes of ≤ 3 diopters (D) (low myopic), 10 eyes between -3 and -6D (moderate myopic), and 10 eyes of ≥ 6D (high myopic). The mean age of subjects was 30.2 years (± 7.6 years; range, 24 to 46 years). A 1050 nm spectral-domain optical coherence tomography (SD-OCT) system, operating at 120 kHz imaging rate, was used in this study to simultaneously capture 3D anatomical images of the choroid and measure intraocular length (IOL) in the subject. The 3D OCT images of the choroid were segmented into superior, inferior, nasal and temporal quadrants, from which the CT was measured, representing radial distance between the outer retinal pigment epithelium (RPE) layer and inner scleral border. Measurements were made within concentric regions centered at fovea centralis, extended to 5 mm away from fovea at 1 mm intervals in the nasal and temporal directions. The measured IOL was the distance from the anterior cornea surface to the RPE in alignment along the optical axis of the eye. Statistical analysis was performed to evaluate CT at each geographic region and observe the relationship between CT and the degree of myopia. Results: For low myopic eyes, the IOL was measured at 24.619 ± 0.016 mm. The CT (273.85 ± 49.01 μm) was greatest under fovea as is in the case of healthy eyes. Peripheral to the fovea, the mean CT decreased rapidly along the nasal direction, reaching a minimum of 180.65 ± 58.25μm at 5 mm away from the fovea. There was less of a change in thickness from the fovea in the temporal direction reaching a minimum of 234.25 ± 42.27 μm. In contrast to the low myopic eyes, for moderate and high myopic eyes, CTs were thickest in temporal region (where CT = 194.94 ± 27.28 and 163 ± 34.89 μm, respectively). Like the low myopic eyes, moderate and high myopic eyes had thinnest CTs in the nasal region (where CT = 100.84 ± 16.75 and 86.64 ± 42.6μm, respectively). High myopic eyes had the longest mean IOL (25.983 ± 0.021mm), while the IOL of moderate myopia was 25.413 ± 0.022 mm (**p < 0.001). The CT reduction rate was calculated at 31.28 μm/D (diopter) from low to moderate myopia, whilst it is 13.49 μm/D from moderate to high myopia. The similar tendency was found for the IOL reduction rate in our study: 0.265 mm/D from low to moderate myopia, and 0.137 mm/D from moderate to high myopia. Conclusion: The CT decreases and the IOL increases gradually with the increase of myopic condition. The current results support the theory that choroidal abnormality may play an important role in the pathogenesis of myopic degeneration.

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Chen, Ping-Hsien, Hung-Yi Lee, Yi-Fen Chen, Yi-Chen Yeh, Kuo-Wei Chang, Ming-Chih Hou, and Wen-Chuan Kuo. "Detection of Oral Dysplastic and Early Cancerous Lesions by Polarization-Sensitive Optical Coherence Tomography." Cancers 12, no. 9 (August 22, 2020): 2376. http://dx.doi.org/10.3390/cancers12092376.

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Detection of oral dysplastic and early-stage cancerous lesions is difficult with the current tools. Half of oral cancers are diagnosed in a late stage. Detection of early stromal change to predict malignant transformation is a new direction in the diagnosis of early-stage oral cancer. The application of new optical tools to image stroma in vivo is under investigation, and polarization-sensitive optical coherence tomography (PS-OCT) is potentially one of those tools. This is a preliminary study to sequentially image oral stromal changes from normal, hyperplasia, and dysplasia to early-stage cancer by PS-OCT in vivo. We used 4-Nitroquinoline-1-oxide drinking water to induce dysplasia and early-stage oral cancer in 19 K14-EGFP-miR-211-GFP transgenic mice. A total of 8 normal, 12 hyperplastic, 11 dysplastic, and 4 early-stage cancerous lesions were enrolled. A new analytic process of PS-OCT imaging was proposed, called an en-face birefringence map. From the birefringence map, the sensitivity, specificity, positive predictive value, and negative predictive values to detect dysplasia and early-stage cancer were 100.00%, 95.00%, 93.75%, and 100.00%, respectively, and the kappa value of these images between two investigators was 0.942. The mean size of malignant lesions detected in this study is 1.66 ± 0.93 mm. This pilot animal study validates the use of PS-OCT to detect small and early-stage oral malignancy with high accuracy and consistency.

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Shibata, Kiyo, Atsushi Fujiwara, Ichiro Hamasaki, Takehiro Shimizu, Reika Kono, Keisuke Kanenaga, Masanori Nakazawa, and Yuki Morizane. "Shape analysis of rectus extraocular muscles with age and axial length using anterior segment optical coherence tomography." PLOS ONE 15, no. 12 (December 23, 2020): e0243382. http://dx.doi.org/10.1371/journal.pone.0243382.

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Purpose This study aimed to evaluate the shape of the extraocular muscles (EOMs) in normal subjects using the en-face images of anterior segment optical coherence tomography (AS-OCT). The EOM insertion and the direction of the muscle fibers were investigated. Subjects and methods A total of 97 healthy normal subjects (194 eyes) at Okayama University Hospital (age, 47.1±21.5 years; range, 8–79 years) participated in the study. A series of 256 tomographic images of the rectus EOMs were captured using the C-scan function of the AS-OCT (CASIA2, TOMEY Co., Japan), and the images were converted to en-face images in multi-TIFF format. The anterior chamber angle to EOM insertion distance (AID) and the angle of the muscle fibers from the insertion site (angle of muscles) were measured from the images. The correlations of AID and angle of muscles with age and axial length were investigated and evaluated. Results AID and angle of muscles were significantly correlated with age or axial length in some EOMs. The AIDs of medial rectus (MR) (P = 0.000) and superior rectus (SR) (P = 0.005) shortened with age. The AIDs of MR (P = 0.001) and inferior rectus (IR) (P = 0.035) elongated with axial length, whereas lateral rectus (LR) (P = 0.013) shortened. The angles of MR (P = 0.001) and LR (P = 0.000) were found to have a more downward direction toward the posterior in older subjects. Conclusion En-face images can be created by AS-OCT, and the shape of the EOMs in normal subjects using these image measurements was available. With the ability to assess the EOMs, AID and angle of muscles are expected give useful information for treating and diagnosing strabismus-related diseases.

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Willemse, Joy, Frank Verbraak, and Johannes de Boer. "Polarization-sensitive optical coherence tomography as a tool to visualize the fiber direction of retinal nerves and peripapillary sclera." EPJ Web of Conferences 238 (2020): 04003. http://dx.doi.org/10.1051/epjconf/202023804003.

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Polarization sensitive optical coherence tomography (PS-OCT) has been used to visualize the orientation of the nerves in the retinal nerve fiber layer (RNFL) and to visualize the orientation of the collagen fibers in peripapillary sclera in retinas of healthy volunteers. Optic axis orientation images clearly visualize the nerve fibers leaving the optic nerve head (ONH) in all radial directions. Sclera orientation images show that the sclera consist of two layers, an inner layer with an orientation parallel to the RNFL orientation, and a deeper layer where the collagen is circularly oriented.

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Kim, Hyeree, XiaoXuan Du, Sungwook Kim, Pilun Kim, Ruchire Eranga Wijesinghe, Byoung-Ju Yun, Kyung-Min Kim, Mansik Jeon, and Jeehyun Kim. "Non-Invasive Morphological Characterization of Rice Leaf Bulliform and Aerenchyma Cellular Regions Using Low Coherence Interferometry." Applied Sciences 9, no. 10 (May 22, 2019): 2104. http://dx.doi.org/10.3390/app9102104.

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Non-invasive investigation of rice leaf specimens to characterize the morphological formation and particular structural information that is beneficial for agricultural perspective was demonstrated using a low coherence interferometric method called swept source optical coherence tomography (SS-OCT). The acquired results non-invasively revealed morphological properties of rice leaf, such as bulliform cells; aerenchyma, parenchyma, and collenchyma layer; and vascular bundle. Beside aforementioned morphologic characteristics, several leaf characteristics associated with cytological mechanisms of leaf rolling (leaf inclination) were examined for the pre-identification of inevitable necrosis and atrophy of leaf tissues by evaluating acute angle information, such as angular characteristics of the external bi-directional angles between the lower epidermis layer and lower mid-vein, and internal angle of lower mid-vein. To further assist the pre-identification, acquired cross-sections were employed to enumerate the small veins of each leaf specimen. Since mutants enlarge leaf angles due to increased cell division in the adaxial epidermis, healthy and abnormal leaf specimens were morphologically and quantitatively compared. Therefore, the results of the method can be used in agriculture, and SS-OCT shows potential as a rigorous investigation method for selecting mutant infected rice leaf specimens rapidly and non-destructively compared to destructive and time consuming gold-standard methods with a lack of precision.

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Sjöstrand, J., R. Rosén, M. Nilsson, and Z. Popovic. "Use of directional optical coherence tomography and selected landmarks to determine foveal topography and microstructure. A strategy to characterize differences between normal and expremature cases." Acta Ophthalmologica 93 (September 23, 2015): n/a. http://dx.doi.org/10.1111/j.1755-3768.2015.0365.

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Hoshino, Masahiro, Taishi Yonetsu, Yoshihito Yuki, Kazunari Inoue, Yoshihisa Kanaji, Eisuke Usui, Tetsumin Lee, and Tsunekazu Kakuta. "Optical Coherence Tomographic Features of Unstable Coronary Lesions Corresponding to Histopathological Intraplaque Hemorrhage Evaluated by Directional Coronary Atherectomy Specimens." JACC: Cardiovascular Interventions 11, no. 14 (July 2018): 1414–15. http://dx.doi.org/10.1016/j.jcin.2018.04.013.

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Cheng, Hsu Chih, and Ming Shiuan Shiu. "Experimental Investigation into High Speed FD-OCT Imaging Based on Orthogonally Polarized Light." Applied Mechanics and Materials 65 (June 2011): 315–18. http://dx.doi.org/10.4028/www.scientific.net/amm.65.315.

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A phase shifting method based on orthogonal polarized light is proposed over complex Fourier domain optical coherence tomography (FD-OCT) to enhance the speed of OCT image scanning and to resist the environmental disturbance such as vibration. In the proposed approach, one simple wave plates (a quarter-wave plate ) are inserted into the system with appropriate rotational angles, the one interference data on orthogonal polarized directions will then manipulate with π/2 phase-shifting algorithm to reduce the scanning frequency. In other words, the proposed approach enables one-shot and full-range FD-OCT.

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Ishida, Akiko, Yukari Yamane, Yasurou Koyama, Manabu Honda, Masahiro Kondo, Yohko Murakawa, and Masaki Tanito. "Conjunctival Chemosis and Annular Ciliochoroidal Detachments Detected by Anterior-Segment Optical Coherence Tomography in a Case of Systemic Lupus Erythematosus." Case Reports in Ophthalmology 12, no. 1 (April 12, 2021): 154–58. http://dx.doi.org/10.1159/000514527.

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A 61-year-old Japanese woman presented to our hospital for treatment of systemic serositis associated with systemic lupus erythematosus (SLE). At the initial ophthalmologic examination, her best-corrected visual acuity was 1.2 and 0.6 in her right and left eyes, respectively. Slit-lamp examination showed marked chemosis in both eyes (OU). Swept source-based, anterior-segment optical coherence tomography (AS-OCT) clearly showed conjunctival elevations corresponding to the chemosis in all scan directions OU. In some scans, hyporeflective spaces with luminal structures corresponding to dilated lymphatic channels and nonluminal structures corresponding to interstitial fluid accumulation were seen clearly under the conjunctival epithelium and/or in the parenchyma. In all scan directions, the supraciliary space was seen clearly, suggesting the presence of an annular ciliochoroidal detachment. Fundus examinations showed retinal edema temporal to the optic nerve head and subfoveal serous retinal detachments OU. Ocular effusions resolved by 2 weeks after the start of steroid pulse therapy, and pleural effusions and ascites resolved and pericardial effusion decreased by 2 months. AS-OCT can be useful for understanding the mechanism(s) of the less common anterior-segment ocular manifestations of SLE.

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Hariri, Amir H., Michael S. Ip, Aniz Girach, Byron L. Lam, M. Dominik Fischer, Eeva-Marja Sankila, Mark Edward Pennesi, et al. "Macular spatial distribution of preserved autofluorescence in patients with choroideremia." British Journal of Ophthalmology 103, no. 7 (October 8, 2018): 933–37. http://dx.doi.org/10.1136/bjophthalmol-2018-312620.

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Background/AimsTo better understand the pattern of degeneration progression in cases with choroideremia.MethodsA cohort of genotypically confirmed choroideremia cases who underwent optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging was studied. Using HEYEX review software, the foveal centre was marked on FAF images under guidance of corresponding OCT images, followed by application of an ETDRS grid. The boundaries of preserved autofluorescence (AF) were manually segmented in each individual ETDRS subfield. The regional distribution of preserved AF was assessed by comparing its area among the various subfields.ResultsA total of 168 eyes from 84 choroideremia cases were enrolled. There was a statistically significant difference in the amount of preserved AF area between inner subfields as determined by one-way analysis of variance (F (3,668)=9.997, p<0.001) and also between outer subfields (F (3,668)=8.348, p<0.001). A Tukey posthoc test revealed that the preserved AF area in the nasal subfields in both the inner and outer subfields was significantly smaller compared with analogue subfields.ConclusionThe asymmetric spatial distribution of preserved AF in choroideremia (corresponding to the stellate shaped nature of these regions) suggests that the progression of degeneration has directional preference.

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Hada, Masahiro, Tomoyo Sugiyama, Yoshihisa Kanaji, and Tsunekazu Kakuta. "Primary percutaneous coronary intervention for a left main bifurcation lesion without stenting using excimer laser with optical coherence tomography guidance: a case report." European Heart Journal - Case Reports 4, no. 1 (February 1, 2020): 1–6. http://dx.doi.org/10.1093/ehjcr/ytaa003.

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Abstract Background Optimal strategy for treating bifurcation lesions or lesions with large thrombus in left main disease remains elusive. Excimer laser coronary angioplasty (ELCA) is a therapeutic option for thrombotic lesions in acute coronary syndrome. Case summary A 68-year-old man with chest pain was transferred to our emergency department, and subsequently diagnosed as inferior ST-segment elevation myocardial infarction (STEMI). Emergent coronary angiography revealed a 75% stenosis in the left main trunk (LMT). Optical coherence tomography (OCT) showed massive thrombus at the distal LMT to the ostial left anterior descending artery (LAD) and left circumflex artery (LCx). ELCA was performed in the three directions from LMT to proximal LAD, proximal LCx, and obtuse marginal branch. OCT after ELCA showed reduction of thrombus and no apparent plaque rupture or calcification, implying that coronary thrombosis was caused by OCT-defined plaque erosion. Intracoronary electrocardiogram of the LCx showed ST-segment elevation which corresponded to inferior ST-segment elevation, whereas no intracoronary electrocardiogram ST-segment elevation was detected for LAD. Taking all of the data including angiographic appearance, OCT-derived residual lumen size and residual thrombus volume, and strategic options into consideration, we completed percutaneous coronary intervention without stent deployment. He has been free from any cardiac events thereafter for 8 months. Discussion Optimal strategy of coronary intervention for bifurcation lesions, especially LMT bifurcations, remains elusive. ELCA may have a potential to safely reduce intracoronary thrombus in patients presenting with acute coronary syndrome with OCT guidance.

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Samel, Nicholas S., and Hiroshi Mashimo. "Application of OCT in the Gastrointestinal Tract." Applied Sciences 9, no. 15 (July 25, 2019): 2991. http://dx.doi.org/10.3390/app9152991.

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Optical coherence tomography (OCT) is uniquely poised for advanced imaging in the gastrointestinal (GI) tract as it allows real-time, subsurface and wide-field evaluation at near-microscopic resolution, which may improve the current limitations or even obviate the need of superficial random biopsies in the surveillance of early neoplasias in the near future. OCT’s greatest impact so far in the GI tract has been in the study of the tubular esophagus owing to its accessibility, less bends and folds and allowance of balloon employment with optimal contact to aid circumferential imaging. Moreover, given the alarming rise in the incidence of Barrett’s esophagus and its progression to adenocarcinoma in the U.S., OCT has helped identify pathological features that may guide future therapy and follow-up strategy. This review will explore the current uses of OCT in the gastrointestinal tract and future directions, particularly with non-endoscopic office-based capsule OCT and the use of artificial intelligence to aid in diagnoses.

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Nguyen, Van, and Yannis Paulus. "Photoacoustic Ophthalmoscopy: Principle, Application, and Future Directions." Journal of Imaging 4, no. 12 (December 12, 2018): 149. http://dx.doi.org/10.3390/jimaging4120149.

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Photoacoustic ophthalmoscopy (PAOM) is a novel, hybrid, non-ionizing, and non-invasive imaging technology that has been used to assess the retina. PAOM can provide both anatomic and functional retinal characterizations with high resolution, high sensitivity, high contrast, and a high depth of penetration. Thus, ocular diseases can be precisely detected and visualized at earlier stages, resulting in an improved understanding of pathophysiology, improved management, and the improved monitoring of retinal treatment to prevent vision loss. To better visualize ocular components such as retinal vessels, choroidal vessels, choroidal neovascularization, retinal neovascularization, and the retinal pigment epithelium, an advanced multimodal ocular imaging platform has been developed by a combination of PAOM with other optical imaging techniques such as optical coherence tomography (OCT), scanning laser ophthalmoscopy (SLO), and fluorescence microscopy. The multimodal images can be acquired from a single imaging system and co-registered on the same image plane, enabling an improved evaluation of disease. In this review, the potential application of photoacoustic ophthalmoscopy in both research and clinical diagnosis are discussed as a medical screening technique for the visualization of various ocular diseases. The basic principle and requirements of photoacoustic ocular imaging are introduced. Then, various photoacoustic microscopy imaging systems of the retina in animals are presented. Finally, the future development of PAOM and multimodal imaging is discussed.

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Journal articles on the topic 'Directional optical coherence tomography'

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