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Optical coherence tomography

Lyndon da Cruz, Kate Fynes, Odysseas Georgiadis, Julie Kerby, Yvonne H Luo, Ahmad Ahmado, Amanda Vernon, Julie T Daniels, Britta Nommiste, Shazeen M Hasan, Sakina B Gooljar, Amanda-Jayne F Carr, Anthony Vugler, Conor M Ramsden, Magda Bictash, Mike Fenster, Juliette Steer, Tricia Harbinson, Anna Wilbrey, Adnan Tufail, Gang Feng, Mark Whitlock, Anthony G Robson, Graham E Holder, Mandeep S Sagoo, Peter T Loudon, Paul Whiting, Peter J Coffey
Age-related macular degeneration (AMD) remains a major cause of blindness, with dysfunction and loss of retinal pigment epithelium (RPE) central to disease progression. We engineered an RPE patch comprising a fully differentiated, human embryonic stem cell (hESC)-derived RPE monolayer on a coated, synthetic basement membrane. We delivered the patch, using a purpose-designed microsurgical tool, into the subretinal space of one eye in each of two patients with severe exudative AMD. Primary endpoints were incidence and severity of adverse events and proportion of subjects with improved best-corrected visual acuity of 15 letters or more...
March 19, 2018: Nature Biotechnology
Paolo Giuseppe Limoli, Enzo Maria Vingolo, Celeste Limoli, Sergio Zaccaria Scalinci, Marcella Nebbioso
This study is aimed at examining whether a suprachoroidal graft of autologous cells can improve best corrected visual acuity (BCVA) and responses to microperimetry (MY) in eyes affected by dry Age-related Macular Degeneration (AMD) over time through the production and secretion of growth factors (GFs) on surrounding tissue. Patients were randomly assigned to each study group. All patients were diagnosed with dry AMD and with BCVA equal to or greater than 1 logarithm of the minimum angle of resolution (logMAR)...
February 12, 2018: Journal of Visualized Experiments: JoVE
Chao Tian, Wei Zhang, Van Phuc Nguyen, Xueding Wang, Yannis M Paulus
Photoacoustic ocular imaging is an emerging ophthalmic imaging technology that can noninvasively visualize ocular tissue by converting light energy into sound waves and is currently under intensive investigation. However, most reported work to date is focused on the imaging of the posterior segment of the eyes of small animals, such as rats and mice, which poses challenges for clinical human translation due to small eyeball sizes. This manuscript describes a novel photoacoustic microscopy (PAM) and optical coherence tomography (OCT) dual-modality system for posterior segment imaging of the eyes of larger animals, such as rabbits...
February 8, 2018: Journal of Visualized Experiments: JoVE
Masanori Tsujimoto, Yukiko Enomoto, Masafumi Miyai, Yusuke Egashira, Toru Iwama
Purpose To determine the best platelet function test for in-stent tissue protrusion following carotid artery stenting (CAS). Methods Patients who underwent CAS were recruited prospectively in this observational study. Combination of aspirin 100 mg/day and clopidogrel 75 mg/day was administered for a minimum of 7 days prior to procedure. Platelet aggregation was measured by light transmittance aggregometry (LTA) following stimulation by adenosine diphosphate (ADP), collagen, and thrombin receptor activating peptide (TRAP) and by the point of care assay, VerifyNow which measures aspirin and thienopyridine reaction units...
January 1, 2018: Journal of International Medical Research
Timm Oberwahrenbrock, Ghislaine L Traber, Sebastian Lukas, Iñigo Gabilondo, Rachel Nolan, Christopher Songster, Lisanne Balk, Axel Petzold, Friedemann Paul, Pablo Villoslada, Alexander U Brandt, Ari J Green, Sven Schippling
Objective: To evaluate the inter-rater reliability of semiautomated segmentation of spectral domain optical coherence tomography (OCT) macular volume scans. Methods: Macular OCT volume scans of left eyes from 17 subjects (8 patients with MS and 9 healthy controls) were automatically segmented by Heidelberg Eye Explorer (v1.9.3.0) beta-software (Spectralis Viewing Module v6.0.0.7), followed by manual correction by 5 experienced operators from 5 different academic centers...
May 2018: Neurology® Neuroimmunology & Neuroinflammation
Yu-Cherng Chang, Keke Liu, Florence Cabot, Sonia H Yoo, Marco Ruggeri, Arthur Ho, Jean-Marie Parel, Fabrice Manns
Optical coherence tomography (OCT) offers new options for imaging the ciliary muscle allowing direct in vivo visualization. However, variation in image quality along the length of the muscle prevents accurate delineation and quantification of the muscle. Quantitative analyses of the muscle are accompanied by variability in segmentation between examiners and between sessions for the same examiner. In processes such as accommodation where changes in muscle thickness may be tens of microns- the equivalent of a small number of image pixels, differences in segmentation can influence the magnitude and potentially the direction of thickness change...
February 1, 2018: Biomedical Optics Express
Nicusor Iftimia, Jesung Park, Gopi Maguluri, Savitri Krishnamurthy, Amanda McWatters, Sharjeel H Sabir
We report the development and the pre-clinical testing of a new technology based on optical coherence tomography (OCT) for investigating tissue composition at the tip of the core biopsy needle. While ultrasound, computed tomography, and magnetic resonance imaging are routinely used to guide needle placement within a tumor, they still do not provide the resolution needed to investigate tissue cellularity (ratio between viable tumor and benign stroma) at the needle tip prior to taking a biopsy core. High resolution OCT imaging, however, can be used to investigate tissue morphology at the micron scale, and thus to determine if the biopsy core would likely have the expected composition...
February 1, 2018: Biomedical Optics Express
Hinnerk Schulz-Hildebrandt, Mario Pieper, Charlotte Stehmar, Martin Ahrens, Christian Idel, Barbara Wollenberg, Peter König, Gereon Hüttmann
Intravital microscopy (IVM) offers the opportunity to visualize static and dynamic changes of tissue on a cellular level. It is a valuable tool in research and may considerably improve clinical diagnosis. In contrast to confocal and non-linear microscopy, optical coherence tomography (OCT) with microscopic resolution (mOCT) provides intrinsically cross-sectional imaging. Changing focus position is not needed, which simplifies especially endoscopic imaging. For in-vivo imaging, here we are presenting endo-microscopic OCT (emOCT)...
February 1, 2018: Biomedical Optics Express
Yang Zhao, Kengyeh K Chu, Will J Eldridge, Evan T Jelly, Michael Crose, Adam Wax
Speckle is an intrinsic noise of interferometric signals which reduces contrast and degrades the quality of optical coherence tomography (OCT) images. Here, we present a frequency compounding speckle reduction technique using the dual window (DW) method. Using the DW method, speckle noise is reduced without the need to acquire multiple frames. A ~25% improvement in the contrast-to-noise ratio (CNR) was achieved using the DW speckle reduction method with only minimal loss (~17%) in axial resolution. We also demonstrate that real-time speckle reduction can be achieved at a B-scan rate of ~21 frames per second using a graphic processing unit (GPU)...
February 1, 2018: Biomedical Optics Express
Viacheslav Mazlin, Peng Xiao, Eugénie Dalimier, Kate Grieve, Kristina Irsch, José-Alain Sahel, Mathias Fink, A Claude Boccara
We present the first full-field optical coherence tomography (FFOCT) device capable of in vivo imaging of the human cornea. We obtained images of the epithelial structures, Bowman's layer, sub-basal nerve plexus (SNP), anterior and posterior stromal keratocytes, stromal nerves, Descemet's membrane and endothelial cells with visible nuclei. Images were acquired with a high lateral resolution of 1.7 µm and relatively large field-of-view of 1.26 mm x 1.26 mm - a combination, which, to the best of our knowledge, has not been possible with other in vivo human eye imaging methods...
February 1, 2018: Biomedical Optics Express
Meng-Tsan Tsai, Jia-Wei Zhang, Kuo-Chen Wei, Chih-Kuang Yeh, Hao-Li Liu
Focused ultrasound (FUS) in combination with microbubbles temporally and locally increases the permeability of the blood-brain barrier (BBB) for facilitating drug delivery. However, the temporary effects of FUS on the brain microstructure and microcirculation need to be addressed. We used label-free optical coherence tomography (OCT) and OCT angiography (OCTA) to investigate the morphological and microcirculation changes in mouse brains due to FUS exposure at different power levels. Additionally, the recovery progress of the induced effects was studied...
February 1, 2018: Biomedical Optics Express
Boy Braaf, Sabine Donner, Ahhyun S Nam, Brett E Bouma, Benjamin J Vakoc
Complex differential variance (CDV) provides phase-sensitive angiographic imaging for optical coherence tomography (OCT) with immunity to phase-instabilities of the imaging system and small-scale axial bulk motion. However, like all angiographic methods, measurement noise can result in erroneous indications of blood flow that confuse the interpretation of angiographic images. In this paper, a modified CDV algorithm that corrects for this noise-bias is presented. This is achieved by normalizing the CDV signal by analytically derived upper and lower limits...
February 1, 2018: Biomedical Optics Express
Laurin Ginner, Tilman Schmoll, Abhishek Kumar, Matthias Salas, Nastassia Pricoupenko, Lara M Wurster, Rainer A Leitgeb
We demonstrate a high-resolution line field en-face time domain optical coherence tomography (OCT) system using an off-axis holography configuration. Line field en-face OCT produces high speed en-face images at rates of up to 100 Hz. The high frame rate favors good phase stability across the lateral field-of-view which is indispensable for digital adaptive optics (DAO). Human retinal structures are acquired in-vivo with a broadband light source at 840 nm, and line rates of 10 kHz to 100 kHz. Structures of different retinal layers, such as photoreceptors, capillaries, and nerve fibers are visualized with high resolution of 2...
February 1, 2018: Biomedical Optics Express
Hyung-Jin Kim, Minji Kim, Min Gyu Hyeon, Youngwoon Choi, Beop-Min Kim
We propose a new method of determining the optical axis (OA), pupillary axis (PA), and visual axis (VA) of the human eye by using dual-depth whole-eye optical coherence tomography (OCT). These axes, as well as the angles "α" between the OA and VA and "κ" between PA and VA, are important in many ophthalmologic applications, especially in refractive surgery. Whole-eye images are reconstructed based on simultaneously acquired images of the anterior segment and retina. The light from a light source is split into two orthogonal polarization components for imaging the anterior segment and retina, respectively...
February 1, 2018: Biomedical Optics Express
Nils Gessert, Matthias Schlüter, Alexander Schlaefer
Tracking the pose of instruments is a central problem in image-guided surgery. For microscopic scenarios, optical coherence tomography (OCT) is increasingly used as an imaging modality. OCT is suitable for accurate pose estimation due to its micrometer range resolution and volumetric field of view. However, OCT image processing is challenging due to speckle noise and reflection artifacts in addition to the images' 3D nature. We address pose estimation from OCT volume data with a new deep learning-based tracking framework...
March 10, 2018: Medical Image Analysis
Jesse D Sengillo, Winston Lee, Takayuki Nagasaki, Kaspar Schuerch, Lawrence A Yannuzzi, K Bailey Freund, Janet Sparrow, Rando Allikmets, Stephen H Tsang
PURPOSE: Mutations in the eyes shut homolog (EYS) gene are a frequent cause of autosomal recessive retinitis pigmentosa (arRP). This study used multi-modal retinal imaging to elucidate genotype-phenotype relationships in EYS-related RP (EYS-RP). DESIGN: Cross-sectional study. METHOD: Multimodal retinal imaging and electrophysiologic testing was assessed for 16 patients with genetic confirmation of EYS-RP. RESULTS: A total of 27 unique EYS variants were identified in 16 patients...
March 14, 2018: American Journal of Ophthalmology
Francisco Javier Irazusta, Guillermo Galeote, Santiago Jimenez-Valero, Juan Caro-Codon, Angel Sanchez-Recalde, Raul Moreno
No abstract text is available yet for this article.
March 8, 2018: JACC. Cardiovascular Interventions
Daniel Walters, Belal Al Khiami, Ehtisham Mahmud, Mitul Patel
PURPOSE: The optical-coherence tomography guided Ocelot catheter has previously been shown to be a safe and effective tool for crossing peripheral chronic total occlusions. However, the existing literature focuses mostly on the superficial femoral artery, without prior evidence of use within the suprainguinal vasculature. CASE SERIES: We present the first known cases of the Ocelot catheter for revascularization of chronic total occlusions in the iliac vasculature...
February 13, 2018: Cardiovascular Revascularization Medicine: Including Molecular Interventions
Xiao Yang, Massoud A Leesar, Hinan Ahmed, Vasili Lendel, Gerardo Rodriguez, Deniz Mutlu, Ian Cawich, Anand Prasad, Meagan Oglesby, Kostas Marmagkiolis, Nathanael E Phillips, Dijkstra Jouke, Joel Michalek, Qianqian Liu, Thomas Milner, Austin McElroy, Taylor Hoyt, Marc D Feldman, Mehmet Cilingiroglu
PURPOSE: To compare OCT identified white thrombus decline, neointimal hyperplasia and clinical outcomes of patients treated with ticagrelor plus aspirin with those patients treated with clopidogrel plus aspirin after peripheral interventions. BACKGROUND: Ticagrelor is a potent platelet inhibitor. In patients with coronary artery disease, ticagrelor and aspirin demonstrated reduced rates of stent thrombosis, compared to aspirin and clopidogrel. The clinical importance of potent antiplatelet inhibition after peripheral endovascular interventions is unknown...
February 23, 2018: Cardiovascular Revascularization Medicine: Including Molecular Interventions
Efrat Fleissig, Mor Pavlovksy, Anat Loewenstein, Dinah Zur, Hadas Newman, Shay Keren, Dafna Goldenberg, Efrat Bar-Ilan, Michaella Goldstein
PURPOSE: To investigate ocular manifestations in patients with vitiligo by multimodal imaging, including optical coherence tomography (OCT), color fundus photography, and fundus autofluorescence (FAF). METHODS: In this prospective, observational clinical study, vitiligo patients underwent ophthalmologic and dermatologic clinical assessment and imaging by spectral-domain OCT, FAF, and color fundus imaging. Ocular echography was performed as indicated. Statistical analysis was performed using paired T test and Pearson correlation...
March 16, 2018: Graefe's Archive for Clinical and Experimental Ophthalmology
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