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    1. Optical coherence tomography for identification of malignant pulmonary nodules based on random forest machine learning algorithm

      Optical coherence tomography for identification of malignant pulmonary nodules based on random forest machine learning algorithm

      Objective: To explore the feasibility of using random forest (RF) machine learning algorithm in assessing normal and malignant peripheral pulmonary nodules based on in vivo endobronchial optical coherence tomography (EB-OCT). Methods: A total of 31 patients with pulmonary nodules were admitted to Department of Respiratory Medicine, Zhongda Hospital, Southeast University, and underwent chest CT, EB-OCT and biopsy. Attenuation coefficient and up to 56 different image features were extracted from A-line and B-scan of 1703 EB-OCT images. Attenuation coefficient and 29 image features with significant p-values were used to analyze the differences between normal and malignant samples. A RF classifier was ...

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    2. The diagnostic accuracy and prognostic value of OCT for the evaluation of the visual function in children with a brain tumour

      The diagnostic accuracy and prognostic value of OCT for the evaluation of the visual function in children with a brain tumour

      Purpose To systematically review the evidence on the diagnostic accuracy and prognostic value of retinal optical coherence tomography (OCT) to detect visual acuity (VA) or visual field (VF) loss in children with a brain tumour. Methods PubMed, Embase and Cochrane Library databases were searched from inception to February 2021. We included studies evaluating retinal OCT and standard visual function parameters (VA and or VF) in children with a brain tumour. Two authors independently extracted data from each included study. They also assessed the methodological quality of the studies using the QUADAS-2 or QUIPS tool. The diagnostic accuracy of OCT was ...

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    3. OCTAVA: An open-source toolbox for quantitative analysis of optical coherence tomography angiography images

      OCTAVA: An open-source toolbox for quantitative analysis of optical coherence tomography angiography images

      Optical coherence tomography angiography (OCTA) performs non-invasive visualization and characterization of microvasculature in research and clinical applications mainly in ophthalmology and dermatology. A wide variety of instruments, imaging protocols, processing methods and metrics have been used to describe the microvasculature, such that comparing different study outcomes is currently not feasible. With the goal of contributing to standardization of OCTA data analysis, we report a user-friendly, open-source toolbox, OCTAVA (OCTA Vascular Analyzer), to automate the pre-processing, segmentation, and quantitative analysis of en face OCTA maximum intensity projection images in a standardized workflow. We present each analysis step, including optimization of filtering ...

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    4. Relationship between the sFlt-1/PlGF ratio and the optical coherence tomographic features of chorioretina in patients with preeclampsia

      Relationship between the sFlt-1/PlGF ratio and the optical coherence tomographic features of chorioretina in patients with preeclampsia

      This study aimed to evaluate the correlation between ophthalmologic factors and the serologic indicator soluble fms-like tyrosine kinase 1 (sFlt-1): placental growth factor (PlGF) ratio in patients with preeclampsia using optical coherence tomography (OCT) and OCT angiography (OCT-A). A total of 52 pregnant patients (104 eyes) diagnosed with preeclampsia were recruited during their hospital stay. The associations between the sFlt-1/PlGF ratio and chorioretinal measurements, including the choroidal thickness (CT), foveal avascular zone, vascular density, and ganglion cell layer+ were evaluated. Central and nasal subfield CT of the left eye (p = 0.039; p = 0.010) and nasal subfield CT ...

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    5. The role of OCT- angiography in predicting anatomical and functional recovery after endoscopic endonasal pituitary surgery: A 1-year longitudinal study

      The role of OCT- angiography in predicting anatomical and functional recovery after endoscopic endonasal pituitary surgery: A 1-year longitudinal study

      Purpose: The purpose of this study was to investigate the changes in structural spectral-domain optical coherence tomography (SD-OCT), OCT Angiography (OCTA) parameters, and visual acuity, 1 year after endoscopic endonasal approach for the removal of an intra-suprasellar pituitary adenoma compressing optic chiasm and compare outcomes with 48 hours postoperative data. Methods: Sixteen eyes of eight patients (4 males, 4 females, mean age 52 ± 11 years) were enrolled in this prospective study. The primary outcome was to evaluate the changes over time before and after surgery, analyzing the Best Corrected Visual Acuity (BCVA), Ganglion Cell Complex (GCC), Retinal Nerve Fiber Layer ...

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    6. Correlations among age, sex, axial length, and subfoveal choroidal thickness in the choriocapillaris structure analyzed using multiple en face image averaging optical coherence tomography angiography

      Correlations among age, sex, axial length, and subfoveal choroidal thickness in the choriocapillaris structure analyzed using multiple en face image averaging optical coherence tomography angiography

      Purpose To analyze the structure of the choriocapillaris in healthy eyes by using averaged en face images acquired using swept source optical coherence tomography angiography and to examine the changes in the macular profile in relation to age, sex, axial length, and choroidal thickness. Methods This prospective, cross-sectional study included 81 eyes of 81 subjects without ophthalmologic or systemic diseases who underwent a full ophthalmologic examination, including 3 × 3-mm macular optical coherence tomography angiography. Four to nine choriocapillaris en face images were registered and averaged. The averaged images were then binarized and analyzed. Results The averaged choriocapillaris images showed a ...

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    7. Impact of stent edge dissection detected by optical coherence tomography after current-generation drug-eluting stent implantation

      Impact of stent edge dissection detected by optical coherence tomography after current-generation drug-eluting stent implantation

      Background Stent edge dissection (SED) is a well-known predictor of worse clinical outcomes. However, impact of SED after current-generation drug-eluting stent (DES) implantation remains unknown since there was no study using only current-generation DES to assess impact of SED. This study aimed to investigate a relationship between SED detected by optical coherence tomography (OCT) and clinical outcomes after current-generation DES implantation. Methods This study enrolled 175 patients receiving OCT after current-generation DES implantation. The SED group was compared with the non-SED group in terms of the primary study endpoints which was the cumulative incidence of major adverse cardiac event (MACE ...

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    8. Impact of image averaging on vessel detection using optical coherence tomography angiography in eyes with macular oedema and in healthy eyes

      Impact of image averaging on vessel detection using optical coherence tomography angiography in eyes with macular oedema and in healthy eyes

      Purpose: To assess the repeatability of multiple automatic vessel density (VD) measurements and the effect of image averaging on vessel detection by optical coherence tomography angiography (OCTA). Methods: An observational study was conducted in a series of healthy volunteers and patients with macular oedema. Five sequential OCTA images were acquired for each eye using the OptoVue HD device. The effect of the averaging of the 5 acquisitions on vessel detection was analysed quantitatively using a pixel-by-pixel automated analysis. In addition, two independent retina experts qualitatively assessed the change in vessel detection in averaged images segmented in 9 boxes and compared ...

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      Mentions: Optovue
    9. Racial and ethnic differences in foveal avascular zone in diabetic and nondiabetic eyes revealed by optical coherence tomography angiography

      Racial and ethnic differences in foveal avascular zone in diabetic and nondiabetic eyes revealed by optical coherence tomography angiography

      Purpose The purpose of this study was to examine whether racial and ethnic differences in retinal microvasculature are detectable with quantitative measures derived from optical coherence tomography angiography (OCTA). Methods OCTA scans and fundus photography were obtained in 447 eyes from 271 patients with and without diabetes between April and October 2018. Fundus photos were graded by the hospital reading center for diabetic retinopathy (DR) severity. Eight OCTA parameters relating to the foveal avascular zone (FAZ), superficial vascular perfusion, and deep vascular perfusion were analyzed for significant differences between race and ethnicity groups, self-reported by patients and organized according to ...

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    10. Effect of axial length on peripapillary microvasculature: An optical coherence tomography angiography study

      Effect of axial length on peripapillary microvasculature: An optical coherence tomography angiography study

      Objective To investigate the effects of axial length (AL) on the peripapillary microvascular density acquired from optical coherence tomography angiography (OCTA). Methods Retrospective observational study. A total of 111 eyes from 111 normal healthy subjects were examined. The subjects were divided into three groups according to the AL: Group 1 (AL: < 24.0 mm; 35 eyes), Group 2 (AL: 24.0–25.99 mm; 37 eyes), and Group 3 (AL: ≥ 26 mm; 39 eyes). Peripapillary OCTA images were acquired using 6× 6 mm angiography scans, and vessel density (VD) and perfusion density (PD) of the superficial capillary plexus were calculated ...

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    11. Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography

      Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography

      This study aimed to theoretically identify the vascular nature of the deep capillary plexus (DCP) by examining patients presenting with both paracentral acute middle maculopathy (PAMM) and prominent middle limiting membrane (p-MLM) sign and p-MLM sign alone in spectral-domain optical coherence tomography (SD-OCT). A retrospective review of the medical records of patients with retinal vein or artery occlusion from two tertiary medical centers was performed. Consecutive patients with a clinical diagnosis of all categories of retinal artery occlusion (RAO) and retinal vein occlusion (RVO) (branch or central and ischemic or non-ischemic) who had undergone SD-OCT imaging from January 2015 to ...

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    12. Swept-source OCT reduces the risk of axial length measurement errors in eyes with cataract and epiretinal membranes

      Swept-source OCT reduces the risk of axial length measurement errors in eyes with cataract and epiretinal membranes

      Aims To compare the biometric data from partial coherence interferometry (PCI) and swept-source OCT (SS-OCT) in patients with age-related cataract and epiretinal membrane (ERM): ERM, ERM with foveoschisis and macular pseudohole. Methods 49 eyes of 49 subjects including 36 ERM, 9 ERM foveoschisis and 4 macular pseudohole were analysed to evaluate the axial length (AL) measurements and the presence of AL measurement errors, defined basing on the shape of the biometric output graphs and on the concordance of AL values between instruments. Eyes with ERM were divided in four stages according to OCT features (i.e. presence/absence of the ...

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    13. Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography

      Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography

      This study aimed to theoretically identify the vascular nature of the deep capillary plexus (DCP) by examining patients presenting with both paracentral acute middle maculopathy (PAMM) and prominent middle limiting membrane (p-MLM) sign and p-MLM sign alone in spectral-domain optical coherence tomography (SD-OCT). A retrospective review of the medical records of patients with retinal vein or artery occlusion from two tertiary medical centers was performed. Consecutive patients with a clinical diagnosis of all categories of retinal artery occlusion (RAO) and retinal vein occlusion (RVO) (branch or central and ischemic or non-ischemic) who had undergone SD-OCT imaging from January 2015 to ...

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    14. Changes in entropy on polarized-sensitive optical coherence tomography images after therapeutic subthreshold micropulse laser for diabetic macular edema: A pilot study

      Changes in entropy on polarized-sensitive optical coherence tomography images after therapeutic subthreshold micropulse laser for diabetic macular edema: A pilot study

      Purpose To investigate the dynamics of the healing process after therapeutic subthreshold micropulse laser (SMPL) for diabetic macular edema (DME) using polarization-sensitive optical coherence tomography (PS-OCT). Methods Patients with treatment-native or previously-treated DME were prospectively imaged using PS-OCT at baseline, 1, 2, 3, and 6 months. The following outcomes were evaluated: changes in the entropy value per unit area (pixel 2 ) in the retinal pigment epithelium (RPE) on the B-scan image; changes in the entropy value in each stratified layer (retina, RPE, choroid) based on the ETDRS grid circle overlaid with en face entropy mapping, not only the whole ETDRS ...

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    15. Detection of retinal changes with optical coherence tomography angiography in mild cognitive impairment and Alzheimer's disease patients: A meta-analysis

      Detection of retinal changes with optical coherence tomography angiography in mild cognitive impairment and Alzheimer's disease patients: A meta-analysis

      Objective To assess retinal microvascular network impairments in the eyes of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) patients with optical coherence tomography angiography (OCTA). Design Systematic review and meta-analysis. Methods A literature search was conducted in the PubMed and EMBASE databases to identify relevant studies detecting retinal microvascular attenuation among AD, MCI patients and cognitively healthy controls (HCs) by OCTA. Data were extracted by Review Manager V.5.4 and Stata V.14.0. Results Eight investigations were included in this meta-analysis, with 150 AD patients, 195 MCI patients and 226 HCs were eligible for meta-analysis. Evidence ...

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    16. Impact of large choroidal vessels on choriocapillaris flow deficit analyses in optical coherence tomography angiography

      Impact of large choroidal vessels on choriocapillaris flow deficit analyses in optical coherence tomography angiography

      Purpose To investigate the impact of large choroidal vessels (LCV) on Choriocapillaris (CC) flow deficit (FD) analyses with swept-source optical coherence tomography angiography (SS-OCTA) Design Prospective, cross-sectional study. Methods Macular 6x6mm SS-OCTA scans were obtained from intermediate age-related macular degeneration (iAMD) and healthy eyes. Images were captured and processed according to most common standards and analyzed for percentage of flow-deficits (FD%) within four 1x1mm squares at the corners of each image. Choroidal thickness (CT), iris color and refraction error were considered as potential influential factors for LCV visibility. A linear mixed model and logistic regression models were calculated for statistical ...

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    17. Diagnosis of retinal disorders from Optical Coherence Tomography images using CNN

      Diagnosis of retinal disorders from Optical Coherence Tomography images using CNN

      An efficient automatic decision support system for detection of retinal disorders is important and is the need of the hour. Optical Coherence Tomography (OCT) is the current imaging modality for the early detection of retinal disorders non-invasively. In this work, a Convolution Neural Network (CNN) model is proposed to classify three types of retinal disorders namely: Choroidal neovascularization (CNV), Drusen macular degeneration (DMD) and Diabetic macular edema (DME). The hyperparameters of the model like batch size, number of epochs, dropout rate, and the type of optimizer are tuned using random search optimization method for better performance to classify different retinal ...

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    18. Repeatability and agreement of white-to-white measurements between slit-scanning tomography, infrared biometry, dual rotating Scheimpflug camera/Placido disc tomography, and swept source anterior segment optical coherence tomography

      Repeatability and agreement of white-to-white measurements between slit-scanning tomography, infrared biometry, dual rotating Scheimpflug camera/Placido disc tomography, and swept source anterior segment optical coherence tomography

      Purpose To assess the agreement and repeatability of horizontal visible iris diameter (HVID) or white-to-white (WTW) measurements between four imaging modalities; combination slit scanning elevation/Placido tomography, infrared biometry, dual rotating scheimpflug camera/Placido tomography, and swept source anterior segment optical coherence tomography (AS-OCT). Methods A prospective study of 35 right eyes of healthy volunteers were evaluated using the Orbscan IIz, IOL Master 700, Galilei G2, and DRI Triton OCT devices. The inter-device agreement and repeatability of HVID/WTW measurements for each device were analysed. Results Mean HVID/WTW values obtained by the Orbscan IIz, IOL Master 700, Galilei G2 ...

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    19. Association between smoking history and optical coherence tomography angiography findings in diabetic patients without diabetic retinopathy

      Association between smoking history and optical coherence tomography angiography findings in diabetic patients without diabetic retinopathy

      Purpose: To investigate any associations between cigarette smoking and retinal microvascular changes in diabetic patients without visible retinopathy. Design: Retrospective, cross-sectional study. Participants: 1099 eyes from 1099 diabetic patients with no clinical evidence of diabetic retinopathy (DR) were included in this study. Methods: Diabetic patients underwent optical coherence tomography angiography (OCTA) scanning at Zuckerberg San Francisco General Hospital and Trauma Center between April 2018 and September 2019. Patient demographic and clinical information was collected. Standard bivariate statistics and multivariate linear regression were performed. Main outcome measures: OCTA parameters included metrics related to the foveal avascular zone (FAZ; area, perimeter, circularity ...

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    20. Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy

      Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy

      Objective This in vitro study characterized and monitored, by Optical Coherence Tomography (OCT) and Fourier Transformed Infrared Spectroscopy (FTIR), the effects of the association of acidulated phosphate fluoride gel (APF-gel) and Nd:YAG (neodymiun:yttrium-aluminum-garnet) laser, as sequencial treatments, in the prevention of incipient enamel caries lesions. Methods 120 human enamel samples were randomized into 3 groups (n = 40): APF-gel (1.23% F - , 4 min.); Laser+APF (Nd:YAG laser irradiation—0.6W, 84.9J/cm 2 , 10Hz, followed by APF-gel); and APF+Laser (APF-gel followed by laser irradiation). The samples were subjected to a 15-day pH-cycling, evaluated by OCT ...

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      Mentions: Thorlabs
    21. A normative database of A-scan data using the Heidelberg Spectralis Spectral Domain Optical Coherence Tomography machine

      A normative database of A-scan data using the Heidelberg Spectralis Spectral Domain Optical Coherence Tomography machine

      Purpose To develop the first normative database of macular and circumpapillary scans with reference values at the level of the A-scan using the Heidelberg Spectralis Optical Coherence Tomography (OCT) machine. Methods This study is a retrospective cross sectional analysis of macular and circumpapillary OCT scans of healthy individuals. All participants had a full ophthalmic examination, including best corrected visual acuity, intraocular pressure, biomicroscopy, posterior segment examination and OCT scan. The volume and thickness of each of the nine Early Treatment Diabetic Retinopathy zones at the macula were analysed for the total retinal thickness, retinal nerve fibre layer (RNFL), ganglion cell ...

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    22. Diagnostic ability of confocal near-infrared reflectance fundus imaging to detect retrograde microcystic maculopathy from chiasm compression. A comparative study with OCT findings

      Diagnostic ability of confocal near-infrared reflectance fundus imaging to detect retrograde microcystic maculopathy from chiasm compression. A comparative study with OCT findings

      Purpose: To evaluate the ability of confocal near-infrared reflectance (NIR) to diagnose retrograde microcystic maculopathy (RMM) in eyes with temporal visual field (VF) loss and optic atrophy from chiasmal compression. To compare NIR findings with optical coherence tomography (OCT) findings in the same group of patients. Methods: Thirty-four eyes (26 patients) with temporal VF loss from chiasmal compression and 41 healthy eyes (22 controls) underwent NIR fundus photography, and macular OCT scanning. VF loss was estimated and retinal layers thickness were measured on OCT. Two examiners blinded to the diagnosis randomly examined NIR images for the presence of hyporeflective abnormality ...

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    23. Repeatability of corneal and epithelial thickness measurements with anterior segment optical coherence tomography in keratoconus

      Repeatability of corneal and epithelial thickness measurements with anterior segment optical coherence tomography in keratoconus

      Purpose: To investigate the repeatability in corneal thickness (CT) and epithelial thickness (ET) measurements using spectral domain anterior segment optical coherence tomography (AS-OCT, REVO NX, Optopol) in keratoconus, and examine the effect of corneal crosslinking (CXL) on repeatability. Methods: A cross-sectional study of 259 eyes of 212 patients with keratoconus attending the corneal disease clinic at a university hospital tertiary referral center were enrolled. Two groups were analysed: eyes with no prior history of CXL (Group A) and eyes with prior CXL (Group B). Repeatability of measurements was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV ...

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    24. Macular vessel density differs in multiple sclerosis and neuromyelitis optica spectrum disorder: An optical coherence tomography angiography study

      Macular vessel density differs in multiple sclerosis and neuromyelitis optica spectrum disorder: An optical coherence tomography angiography study

      Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are inflammatory and demyelinating diseases that commonly manifest with optic neuritis (ON) but differ in the pathogenic mechanism. Although it was shown that retinal vessels might alter in MS and NMOSD, a comparative study has not been reported. This study evaluated the macular vessel density in 40 MS patients, 13 NMOSD patients, and 20 controls using optical coherence tomography angiography. The vessel density of superficial capillary plexus (SCP) was significantly lower in ON eyes (MS+ON, NMOSD+ON) than in non-ON eyes (MS-ON, NMOSD-ON) and controls. The density of deep capillary ...

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      Mentions: Optovue
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