Johns Hopkins University

Variability of Vascular Reactivity in the Retina and Choriocapillaris to Oxygen and Carbon Dioxide Using Optical Coherence Tomography Angiography

Purpose: To investigate the regional and layer-specific vascular reactivity of the healthy human retina and choriocapillaris to changes in systemic carbon dioxide or oxygen. Methods: High-resolution 3 × 3-mm2 optical coherence tomography angiography (OCTA) images were acquired from the central macula, temporal macula, and peripapillary retina while participants were exposed to three gas breathing conditions—room air, 5%CO2, and 100% O2. OCTA from all three regions were extracted and the apparent skeletonized vessel density (VSD) was assessed. The mean flow deficit sizes (MFDSs) of the choriocapillaris were also assessed. Repeated-measures analysis of variance was used to compare the ratio of intrasubject VSD change induced by the gas conditions from baseline in the superficial retinal layer (SRL) and deep retinal layer (DRL) for each retinal region independently, as well as the MFDS of the choriocapillaris. We also compared the vessel reactivity between the retinal capillaries an...

Associations of Midlife and Late-Life Blood Pressure Status With Late-Life Retinal OCT Measures

Purpose: To explore the relationship of long-term blood pressure (BP) patterns with late-life optical coherence tomography (OCT) structural measures reflecting optic nerve health. Methods: Participants in this community-based cohort study of black and white individuals were part of the Atherosclerosis Risk in Communities study and the nested Eye Determinants of Cognition (EyeDOC) study. Participants had BP measured six times from 1987 to 2017 and were categorized into five BP patterns: sustained normotension; midlife normotension, late-life hypertension (systolic BP [SBP] >140 mmHg or diastolic BP [DBP] >90 mmHg or antihypertensive medication use); sustained hypertension; midlife normotension, late-life hypotension (SBP <90 mmHg or DBP <60 mmHg); and midlife hypertension, late-life hypotension. Multivariable linear regression modeling was used to evaluate associations between BP patterns and late-life OCT ganglion cell complex (GCC) and peripapillary retinal nerve fib...

Evidence-Based Guidelines for the Number of Peripapillary OCT Scans Needed to Detect Glaucoma Worsening

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Purpose To estimate the number of OCT scans necessary to detect moderate and rapid rates of retinal nerve fiber layer (RNFL) thickness worsening at different levels of accuracy using a large sample of glaucoma and glaucoma-suspect eyes. Design Descriptive and simulation study. Participants Twelve thousand one hundred fifty eyes from 7392 adult patients with glaucoma or glaucoma-suspect status followed up at the Wilmer Eye Institute from 2013 through 2021. All eyes had at least 5 measurements of RNFL thickness on the Cirrus OCT (Carl Zeiss Meditec) with signal strength of 6 or more. Methods Rates of RNFL worsening for average RNFL thickness and for the 4 quadrants were measured using linear regression. Simulations were used to estimate the accuracy of detecting worsening—defined as the percentage of patients in whom the true rate of RNFL worsening was at or less than different criterion rates of worsening when the OCT-measured rate was also at or less than these criterion rate...

Deep learning-based optical coherence tomography image analysis of human brain cancer

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Real-time intraoperative delineation of cancer and non-cancer brain tissues, especially in the eloquent cortex, is critical for thorough cancer resection, lengthening survival, and improving quality of life. Prior studies have established that thresholding optical attenuation values reveals cancer regions with high sensitivity and specificity. However, threshold of a single value disregards local information important to making more robust predictions. Hence, we propose deep convolutional neural networks (CNNs) trained on labeled OCT images and co-occurrence matrix features extracted from these images to synergize attenuation characteristics and texture features. Specifically, we adapt a deep ensemble model trained on 5,831 examples in a training dataset of 7 patients. We obtain 93.31% sensitivity and 97.04% specificity on a holdout set of 4 patients without the need for beam profile normalization using a reference phantom. The segmentation maps produced by parsing the OCT volume an...

Effects of Myopia on Rates of Change in Optical Coherence Tomography Measured Retinal Layer Thicknesses in People with Multiple Sclerosis and Healthy Controls

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Purpose To quantify the associations of myopia with longitudinal changes in retinal layer thicknesses in people with multiple sclerosis (PwMS) and healthy controls (HC). Methods A cohort of PwMS and HC with recorded refractive error (RE) prospectively scanned on Cirrus HD-OCT at the Johns Hopkins MS Center was assessed for inclusion. Exclusion criteria included OCT follow-up < 6 months, ocular comorbidities, incidental OCT pathologies, and inadequate scan quality. Eyes were classified as having high myopia (HM) (RE≤ −6 diopters), low myopia (LM) (RE> −6 and ≤ −3 diopters), or no myopia (NM) (RE> −3 and ≤ +2.75). Linear mixed-effects regression models were used in analyses. Results A total of 213 PwMS (eyes: 67 HM, 98 LM, 207 NM) and 80 HC (eyes: 26 HM, 37 LM, 93 NM) were included. Baseline average ganglion cell/inner plexiform (GCIPL) and peri-papillary retinal nerve fiber layer ...

Convolutional neural network-based common-path optical coherence tomography A-scan boundary-tracking training and validation using a parallel Monte Carlo synthetic dataset

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We present a parallel Monte Carlo (MC) simulation platform for rapidly generating synthetic common-path optical coherence tomography (CP-OCT) A-scan image dataset for image-guided needle insertion. The computation time of the method has been evaluated on different configurations and 100000 A-scan images are generated based on 50 different eye models. The synthetic dataset is used to train an end-to-end convolutional neural network (Ascan-Net) to localize the Descemet's membrane (DM) during the needle insertion. The trained Ascan-Net has been tested on the A-scan images collected from the ex-vivo human and porcine cornea as well as simulated data and shows improved tracking accuracy compared to the result by using the Canny-edge detector. ( Read Full Article )

Optical Coherence Tomography Features for Identifying Posttreatment Complete Polypoidal Regression in Polypoidal Choroidal Vasculopathy

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Purpose: To determine accuracy and relative risk (RR) of posttreatment optical coherence tomography (OCT) features in identifying complete or incomplete polypoidal regression in polypoidal choroidal vasculopathy (PCV). Design: Validity analysis. Methods: Treatment-naive PCV eyes undergoing OCT and indocyanine green angiography (ICGA) at baseline and posttreatment were included. Two graders confirmed diagnosis and identified posttreatment complete or incomplete regression on ICGA. Two other graders classified OCT characteristics of pigment epithelial detachment (PED) (polypoidal lesion) based on 5 prespecified features: "A," no PED; "B," PED with internal homogeneous reflectivity with predominant "BUN" (blended retinal pigment epithelium with underlying structure) sign; "C," PED with internal homogeneous reflectivity with minimal "BUN"; "D," heterogeneous PED; and "E," PED with hyporeflectivity. Results: Among 130 polypoidal lesions (65 pretreatment and 65 posttreatment) of 39 PCV ey...

Visible Light Optical Coherence Tomography of Peripapillary Retinal Nerve Fiber Layer Reflectivity in Glaucoma

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Purpose: To evaluate the clinical utility of visible light optical coherence tomography (VIS-OCT) and to test whether VIS-OCT reflectivity and spectroscopy of peripapillary retinal nerve fiber layer (pRNFL) are correlated with severity of glaucoma, compared with standard-of-care OCT thickness measurements. Methods: In total 54 eyes (20 normal, 17 suspect/preperimetric glaucoma [GS/PPG], 17 perimetric glaucoma [PG]) were successfully imaged with complete datasets. All the eyes were scanned by a custom-designed dual-channel device that simultaneously acquired VIS-OCT and near-infrared OCT (NIR-OCT) images. A 5 × 5 mm2 scan was taken of the pRNFL. The pRNFL reflectivity was calculated for both channels and the spectroscopic marker was quantified by pVN, defined as the ratio of VIS-OCT to NIR-OCT pRNFL reflectivity. The results were compared with ophthalmic examinations and Zeiss Cirrus OCT. Results: VIS-OCT pRNFL reflectivity significantly, sequentially decreased from normal to G...

Comparative Study of Conventional and Ultrahigh-resolution Optical Coherence Tomography Imaging in Esophageal Neoplasia

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Early diagnosis of esophageal cancer can be enhanced by the application of optical coherence tomography (OCT) to gastrointestinal endoscopy. One of the most salient examples is the use of OCT to augment the detection of dysplasia during Barrett's esophagus (BE) surveillance, the established precursor to esophageal adenocarcinoma (EAC). 1 , 2 A previously commercially available balloon-based imaging catheter system, also known as volumetric laser endomicroscopy (VLE), was designed to provide circumferential esophageal imaging at the time of endoscopy. The VLE system uses a 1300 nm wavelength-swept laser and provides images with an axial resolution of 7 µm up to a depth of 3 mm. VLE is capable of resolving microarchitectural features associated with early neoplasia in BE including irregular glandular morphology and increased surface signal intensity. 3 Scoring systems that incorporate these features are associated with a sensitivity of 76-83% and specificity of 71-79% in the dia...

Visual Pathway Involvement in NMDA Receptor Encephalitis: A Clinical, Optical Coherence Tomography, and 18-Fluorodeoxyglucose PET/CT Approach

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Background: Anti-NMDA receptor (NMDAR) encephalitis patients have been reported to exhibit visual dysfunction without retinal thinning. The objective of our study was to examine the involvement of the visual pathway structure and function in anti-NMDAR encephalitis by assessing postrecovery visual function and retinal structure, and acute-phase occipital cortex function. Methods: In this cross-sectional study, patients diagnosed with anti-NMDAR encephalitis per consensus criteria underwent postrecovery visual acuity (VA) testing and optical coherence tomography (OCT) with automated retinal layer segmentation. Clinical data and acute-phase brain 18F-fluorodeoxyglucose (FDG) PET/CT (performed within 90 days of symptom onset, assessed qualitatively and semi-quantitatively) were retrospectively analyzed. VA and OCT measures were compared between anti-NMDAR and age, sex, and race-matched healthy controls (HC). When available, FDG-PET/CT metabolism patterns were analyzed for correlations ...

Association of Serum Neurofilament Light Chain With Inner Retinal Layer Thinning in Multiple Sclerosis

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Background and Objectives Serum neurofilament light chain (sNfL) and optical coherence tomography (OCT)–derived retinal measures (including peripapillary retinal nerve fiber layer [pRNFL] and macular ganglion cell layer/inner plexiform layer [GCIPL] thickness) have been proposed as biomarkers of neurodegeneration in multiple sclerosis (MS). However, studies evaluating the associations between sNfL and OCT-derived retinal measures in MS are limited. Methods In this retrospective analysis of a longitudinal, observational, single-center cohort study, sNfL levels were measured in people with MS and healthy controls (HCs) using single molecule array. Participants with MS were followed with serial OCT for a median follow-up of 4.5 years. Eyes with optic neuritis (ON) within 6 months of baseline OCT or ON during follow-up were excluded. Age-normative cutoffs of sNfL were derived using the HC data, and MS participants with sNfL greater than the 97.5th percentile for age were classifie...

Evidence based guidelines for the number of peripapillary OCT scans needed to detect glaucoma worsening

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Objective Estimate the number of OCT scans necessary to detect moderate and rapid rates of retinal nerve fiber layer (RNFL) thickness worsening at different levels of accuracy using a large sample of glaucoma and glaucoma-suspect eyes. Design Descriptive and simulation study Participants 12,150 eyes from 7,392 adult patients with glaucoma or glaucoma-suspect status followed at the Wilmer Eye Institute from 2013-2021. All eyes had at least 5 measurements of RNFL thickness on the Zeiss Cirrus OCT with signal strength of 6 or greater. Methods Rates of RNFL worsening for average RNFL thickness and for the four quadrants were measured using linear regression. Simulations were used to estimate the accuracy of detecting worsening — defined as the percentage of cases where the true rate of RNFL worsening was at or below different criterion rates of worsening when the OCT measured rate was also at or below these criterion rates — for different testing frequencies and strategies. ...

Disentangled Representation Learning for OCTA Vessel Segmentation with Limited Training Data

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Optical coherence tomography angiography (OCTA) is an imaging modality that can be used for analyzing retinal vasculature. Quantitative assessment of en face OCTA images requires accurate segmentation of the capillaries. Using deep learning approaches for this task faces two major challenges. First, acquiring sufficient manual delineations for training can take hundreds of hours. Second, OCTA images suffer from numerous contrast-related artifacts that are currently inherent to the modality and vary dramatically across scanners. We propose to solve both problems by learning a disentanglement of an anatomy component and a local contrast component from paired OCTA scans. With the contrast removed from the anatomy component, a deep learning model that takes the anatomy component as input can learn to segment vessels with a limited portion of the training images being manually labeled. Our method demonstrates state-of-the-art performance for OCTA vessel segmentation. ( Read Full Arti...

Association of Optical Coherence Tomography and Optical Coherence Tomography Angiography Retinal Features With Visual Function in Older Adults

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Importance Although there is abundant evidence relating neuronal and vascular optical coherence tomography (OCT) and OCT angiography (OCTA) measures to retinal disease, data on the normative distribution of retinal features and their associations with visual function in a healthy, older, community-based population are sparse. Objectives To characterize the normative OCT and OCTA measures in older adults and describe their associations with visual function. Design, Setting, and Participants This was a cross-sectional, observational study conducted from May 17, 2017, to May 31, 2019. The study included a community-based sample. Participants in the Atherosclerosis Risk in Communities study from Jackson, Mississippi (all self-reported Black participants), and Washington County, Maryland (all self-reported White participants), were recruited in the Eye Determinants of Cognition study (EyeDOC). Data analyses were conducted from June 14, 2020, to May 31, 2021. Main Outcomes and Measures Re...

Vitamin A deficiency and the retinal “double carrot” sign with optical coherence tomography

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Background Spectral-domain optical coherence tomography (SD-OCT) and full-field electroretinography (ERG) allow retinal assessment with vitamin A deficiency (VAD). Using SD-OCT, this study aimed to characterize and follow a novel retinal abnormality in patients with VAD and intramuscular supplementation. Methods Patients with VAD were retrospectively reviewed, including SD-OCT and electroretinography. Results Three patients had VAD following bariatric or colon surgery and varying supplementation. All had nyctalopia, extinguished scotopic rod-specific function with ERG, and decreased serum vitamin A. None demonstrated surface abnormalities. All received intramuscular vitamin A with subjective resolution of symptoms. On SD-OCT, four of six eyes exhibited homogenous foveal hyperreflectivity anterior to retinal pigment epithelium-Bruch complex, reminiscent of a “double carrot”, which improved following supplementation. ERG findings demonstrated improved scotopic rod-specific...

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