Ultrahigh resolution optical coherence tomography using a superluminescent light source

A superluminescent Ti:Al2O3 crystal is demonstrated as a light source for ultrahigh resolution optical coherence tomography (OCT). Single spatial mode, fiber coupled output powers of ~40 μW can be generated with 138 nm bandwidth using a 5 W frequency doubled, diode pumped laser, pumping a thin Ti:Al2O3 crystal. Ultrahigh resolution OCT imaging is demonstrated with 2.2 μm axial resolution in air, or 1.7 μm in tissue, with >86 dB sensitivity. This light source provides a simple and robust alternative to femtosecond lasers for ultrahigh resolution OCT imaging

Endoscopic Optical Coherence Tomography for Clinical Gastroenterology

Optical coherence tomography (OCT) is a real-time optical imaging technique that is similar in principle to ultrasonography, but employs light instead of sound waves and allows depth-resolved images with near-microscopic resolution. Endoscopic OCT allows the evaluation of broad-field and subsurface areas and can be used ancillary to standard endoscopy, narrow band imaging, chromoendoscopy, magnification endoscopy, and confocal endomicroscopy. This review article will provide an overview of the clinical utility of endoscopic OCT in the gastrointestinal tract and of recent achievements using state-of-the-art endoscopic 3D-OCT imaging systems. Keywords: optical coherence tomography; optical biopsy; endoscopic imaging; Barrett’s esophagus; inflammatory bowel diseaseNational Institutes of Health (U.S.) (Grant R01-CA75289-17)National Institutes of Health (U.S.) (Grant R44-CA101067-06)National Institutes of Health (U.S.) (Grant R01-CA178636-01)National Institutes of Health (U.S.) (Grant R44EY022864-01)National Institutes of Health (U.S.) (Grant R01-EY011289-27)National Institutes of Health (U.S.) (Grant R01-NS057476-05)United States. Air Force Office of Scientific Research (Grant FA9550-12-1-0499)United States. Air Force Office of Scientific Research (Grant FA9550-10-1-0551

A study to assess COPD Symptom-based Management and to Optimise treatment Strategy in Japan (COSMOS-J) based on GOLD 2011

Background and objective: The Global initiative for chronic Obstructive Lung Disease(GOLD) Committee has proposed a chronic obstructive pulmonary disease (COPD) assessment framework focused on symptoms and on exacerbation risk. This study will evaluate a symptom and exacerbation risk-based treatment strategy based on GOLD in a real-world setting in Japan. Optimal management of COPD will be determined by assessing symptoms using the COPD Assessment Test (CAT) and by assessing the frequency of exacerbations. Methods: This study (ClinicalTrials.gov identifier: NCT01762800) is a 24-week, multicenter, randomized, double-blind, double-dummy, parallel-group study. It aims to recruit 400 patients with moderate-to-severe COPD. Patients will be randomized to receive treatment with either salmeterol/fluticasone propionate (SFC) 50/250μg twice daily or with tiotropium bromide 18μg once daily. Optimal management of patients will be assessed at four-weekly intervals and, if patients remain symptomatic, as measured using the CAT, or experience an exacerbation, they have the option to step up to treatment with both drugs, ie, SFC twice daily and tiotropium once daily (TRIPLE therapy). The primary endpoint of the study will be the proportion of patients who are able to remain on the randomized therapy. Results: No data are available. This paper summarizes the methodology of the study in advance of the study starting. Conclusion: The results of this study will help physicians to understand whether TRIPLE therapy is more effective than either treatment strategy alone in controlling symptoms and exacerbations in patients with moderate-to-severe COPD. It will also help physicians to understand the GOLD recommendation work in Japan

Analysis of Peripapillary Atrophy Using Spectral Domain Optical Coherence Tomography

Objective To study retinal morphologic changes around the optic disc in patients with peripapillary atrophy (PPA) with high-resolution spectral domain optical coherence tomography (SD OCT). Design Cross-sectional, retrospective analysis. Participants A total of 103 eyes of 73 patients with PPA and 21 eyes of 12 normal patients seen at the New England Eye Center, Tufts Medical Center, between January 2007 and August 2009. Methods Spectral domain optical coherence tomography images taken through the region of PPA were quantitatively and qualitatively analyzed. Inclusion criteria included eyes with at least 300 μm of temporal PPA as detected on color fundus photographs. The study population was divided into subgroups according to the following clinical diagnoses: glaucoma (n=13), age-related macular degeneration (n=11), high myopia (n=11), glaucoma and high myopia (n=3), and optic neuropathy (n=11). Fifty-four patients were classified with other diagnoses. By using OCT software, retinal thickness and retinal nerve fiber layer (RNFL) thickness were both manually measured perpendicular to the internal limiting membrane and retinal pigment epithelium (RPE) 300 μm temporal to the optic disc, within the region of PPA. Qualitative analysis for morphologic changes in the atrophic area was also performed. Main Outcome Measures Qualitative assessment and quantitative measures of retinal and RNFL thickness in PPA. Results The study group was categorized by 6 characteristics demonstrated in the area of PPA by SD OCT: RPE loss with accompanying photoreceptor loss, RPE disruption, RNFL thickening with plaque-like formation, intraretinal cystic changes, inner and outer retinal thinning, and abnormal retinal sloping. Statistical analysis of measurements revealed a statistically significant difference in the total retinal thickness between normal eyes and eyes with PPA (P=0.0005), with normal eyes 15% thicker than the eyes with PPA; however, the RNFL thickness was not significantly different between the normal eyes and the eyes with PPA (P=0.05). Conclusions Eyes with PPA manifest characteristic retinal changes that can be described via SD OCT.National Institutes of Health (U.S.) (Contract R01-EY11289-24)National Institutes of Health (U.S.) (Contract R01-EY13178-10)National Institutes of Health (U.S.) (Contract R01-EY013516-07)United States. Air Force Office of Scientific Research (FA9550-07-1-0101)United States. Air Force Office of Scientific Research (FA9550-07-1-0014)Massachusetts Lions Eye Research Fund, Inc

Analysis of Choroidal Thickness in Age-Related Macular Degeneration Using Spectral-Domain Optical Coherence Tomography

Purpose To understand the relationship between choroidal thickness and various disease factors in patients with age-related macular degeneration (AMD) using spectral-domain optical coherence tomography. Design Cross-sectional, retrospective analysis. Methods Fifty-seven eyes of 47 patients with wet and dry AMD seen between November 2009 and January 2010 at the New England Eye Center, Boston, Massachusetts, were analyzed. Choroidal thickness was measured by 2 independent observers at 11 sites with high-definition horizontal 1-line raster scans through the foveal center. A retrospective chart review was performed to obtain data concerning duration of disease, number of intravitreal anti–vascular endothelial growth factor injections, visual acuity, lens status, and concomitant retinal pathologic features. The Pearson correlation and Student t test were used for statistical analysis for assessment of choroidal thickness changes in wet and dry AMD. Results The choroid in eyes with wet and dry AMD demonstrated a wide range of thicknesses above and below the normal mean (range, 77.5 to 399.5 μm; standard deviation [SD], 90.2). Nearly one third (33.3%) of the eyes with AMD measured less than 1 SD below the mean. Eyes with wet AMD demonstrated a mean subfoveal choroidal thickness of 194.6 μm (SD, 88.4; n = 40) compared with 213.4 μm (SD, 92.2; n = 17) in the dry AMD group. The choroidal thickness in eyes with dry AMD was correlated inversely with age (r = −0.703; P = .002); however, analysis of the number of intravitreal anti–vascular endothelial growth factor injections, number of years of disease, and visual acuity failed to demonstrate any significant correlations with choroidal thickness. Conclusions This study demonstrated that choroidal thickness can be measured by spectral-domain optical coherence tomography and that variable choroidal thickness exists among patients with the clinical diagnosis of wet and dry AMD. However, it is unclear at this time why in some eyes, choroidal thickness either increases or decreases with the disease. Further studies need to be carried out to understand the significance of choroidal thickness with respect to visual function and disease progression over time.Research to Prevent Blindness, Inc. (United States) (Challenge Grant)National Institutes of Health (U.S.) (Grant R01-EY11289-23)National Institutes of Health (U.S.) (Grant R01-EY13178-10)National Institutes of Health (U.S.) (Grant R01-EY013516-07)United States. Air Force Office of Scientific Research (Grant FA9550-07-1-0101)United States. Air Force Office of Scientific Research (Grant FA9550-07-1-0014)Massachusetts Lions Eye Research Fund, Inc

Choroidal Imaging Using Spectral-Domain Optical Coherence Tomography

Author Manuscript received 2012 June 22.Background: A structurally and functionally normal choroidal vasculature is essential for retinal function. Therefore, a precise clinical understanding of choroidal morphology should be important for understanding many retinal and choroidal diseases. Methods: PUBMED ( http://www.ncbi.nlm.nih.gov/site...) was used for most of the literature search for this article. The criterion for inclusion of an article in the references for this review was that it included materials about both the clinical and the basic properties of choroidal imaging using spectral-domain optical coherence tomography. Results: Recent reports show successful examination and accurate measurement of choroidal thickness in normal and pathologic states using spectral-domain optical coherence tomography systems. This review focuses on the principles of the new technology that make choroidal imaging using optical coherence tomography possible and on the changes that subsequently have been documented to occur in the choroid in various diseases. Additionally, it outlines future directions in choroidal imaging. Conclusion: Optical coherence tomography is now proven to be an effective noninvasive tool to evaluate the choroid and to detect choroidal changes in pathologic states. Additionally, choroidal evaluation using optical coherence tomography can be used as a parameter for diagnosis and follow-up.Research to Prevent Blindness, Inc. (United States) (Unrestricted Grant)National Institutes of Health (U.S.) (Contract RO1-EY11289-25)National Institutes of Health (U.S.) (Contract R01-EY13178-10)National Institutes of Health (U.S.) (Contract R01-EY013516-07)National Institutes of Health (U.S.) (Contract R01-EY019029-02)United States. Air Force Office of Scientific Research (Grant FA9550-10-1-0551)United States. Air Force Office of Scientific Research (FA9550-10-1-0063

Computer-Aided Analysis of Gland-Like Subsurface Hyposcattering Structures in Barrett’s Esophagus Using Optical Coherence Tomography

(1) Background: Barrett's esophagus (BE) is a complication of chronic gastroesophageal reflux disease and is a precursor to esophageal adenocarcinoma. The clinical implication of subsurface glandular structures of Barrett's esophagus is not well understood. Optical coherence tomography (OCT), also known as volumetric laser endomicroscopy (VLE), can assess subsurface glandular structures, which appear as subsurface hyposcattering structures (SHSs). The aim of this study is to develop a computer-aided algorithm and apply it to investigate the characteristics of SHSs in BE using clinical VLE data; (2) Methods: SHSs were identified with an initial detection followed by machine learning. Comprehensive SHS characteristics including the number, volume, depth, size and shape were quantified. Clinical VLE datasets collected from 35 patients with a history of dysplasia undergoing BE surveillance were analyzed to study the general SHS distribution and characteristics in BE. A subset of radiofrequency ablation (RFA) patient data were further analyzed to investigate the pre-RFA SHS characteristics and post-RFA treatment response; (3) Results: SHSs in the BE region were significantly shallower, more vertical, less eccentric, and more regular, as compared with squamous SHSs. SHSs in the BE region which became neosquamous epithelium after RFA were shallower than those in the regions that remained BE. Pre-ablation squamous SHSs with higher eccentricity correlated strongly with larger reduction of post-ablation BE length for less elderly patients; (4) Conclusions: The computer algorithm is potentially a valuable tool for studying the roles of SHSs in BE. Keywords: Barrett;s esophagus; glands; optical coherence tomographyNational Institutes of Health (U.S.) (Grant R01-CA075289-19)National Institutes of Health (U.S.) (Grant RO1-CA178636-04)National Institutes of Health (U.S.) (Grant R01-EY011289-30)United States. Air Force Office of Scientific Research (Contract FA9550-12-1-0551)United States. Air Force Office of Scientific Research (Contract FA9550-15-1-0473

OCT Angiography-based Evaluation of the Choriocapillaris in Neovascular Age Related Macular Degeneration

Neovascular age-related macular degeneration (AMD) can lead to rapid, irreversible vision loss in untreated eyes. While the pathogenesis of neovascular AMD remains incompletely understood, the choriocapillaris has been hypothesized as the initial site of injury. Due to limitations of dye-based angiography, in vivo imaging of the choriocapillaris has been a longstanding challenge. However, the clinical introduction of optical coherence tomography angiography (OCTA) has enabled researchers and clinicians to noninvasively image the choriocapillaris vasculature, allowing the evaluation of the choriocapillaris in eyes with a variety of pathologies. In this perspective, we review important OCTA-based findings regarding choriocapillaris impairment in neovascular AMD and discuss limitations and future directions of OCTA technologies in the context of this disease

MEMS tunable VCSEL light source for ultrahigh speed 60kHz - 1MHz axial scan rate and long range centimeter class OCT imaging

This paper demonstrates new wavelength swept light source technology, MEMS tunable VCSELs, for OCT imaging. The VCSEL achieves a combination of ultrahigh sweep speeds, wide spectral tuning range, flexibility in sweep trajectory, and extremely long coherence length, which cannot be simultaneously achieved with other technologies. A second generation prototype VCSEL is optically pumped at 980nm and a low mass electrostatically tunable mirror enables high speed wavelength tuning centered at ~1310nm with ~110nm of tunable bandwidth. Record coherence length >100mm enables extremely long imaging range. By changing the drive waveform, a single 1310nm VCSEL was driven to sweep at speeds from 100kHz to 1.2MHz axial scan rate with unidirectional and bidirectional high duty cycle sweeps. We demonstrate long range and high resolution 1310nm OCT imaging of the human anterior eye at 100kHz axial scan rate and imaging of biological samples at speeds of 60kHz - 1MHz. A first generation 1050nm device is shown to sweep over 100nm. The results of this study suggest that MEMS based VCSEL swept light source technology has unique performance characteristics and will be a critical technology for future ultrahigh speed and long depth range OCT imaging.National Institutes of Health (U.S.) (2R44CA10167-05)National Institutes of Health (U.S.) (R01-EY011289-25)National Institutes of Health (U.S.) (R01-EY01356-06)National Institutes of Health (U.S.) (R01-EY013178-11)National Institutes of Health (U.S.) (R01-CA075289-15)United States. Air Force Office of Scientific Research (FA9550-10-1-0063)United States. Air Force Office of Scientific Research (FA9550-10-1-0551)Thorlabs, Inc