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Spatial Correspondence Between Intraretinal Fluid, Subretinal Fluid, and Pigment Epithelial Detachment in Neovascular Age-Related Macular Degeneration
摘要： PURPOSE. To identify the spatial distribution of exudative features of choroidal neovascularization in neovascular age-related macular degeneration (nAMD) based on the localization of intraretinal cystoid fluid (IRC), subretinal fluid (SRF), and pigment-epithelial detachment (PED). METHODS. This retrospective cross-sectional study included spectral-domain optical coherence tomography volume scans (6 3 6 mm) of 1341 patients with treatment-na¨?ve nAMD. IRC, SRF, and PED were detected on a per-voxel basis using fully automated segmentation algorithms. Two subsets of 37 volumes each were manually segmented to validate the automated results. The spatial correspondence of components was quantified by computing proportions of IRC-, SRF-, or PED-presenting A-scans simultaneously affected by the respective other pathomorphologic components on a per-patient basis. The median across the population is reported. Odds ratios between pairs of lesions were calculated and tested for significance pixel wise. RESULTS. Automated image segmentation was successful in 1182 optical coherence tomography volumes, yielding more than 61 million A-scans for analysis. Overall, 81% of eyes showed IRC, 95% showed SRF, and 92% showed PED. IRC-presenting A-scans also showed SRF in a median 2.5%, PED in 32.9%. Of the SRF-presenting A-scans, 0.3% demonstrated IRC, 1.4% PED. Of the PED-presenting A-scans, 5.2% contained IRC, 2.0% SRF. Similar patterns were observed in the manually segmented subsets and via pixel-wise odds ratio analysis. CONCLUSIONS. Automated analyses of large-scale datasets in a cross-sectional study of 1182 patients with active treatment-na¨?ve nAMD demonstrated low spatial correlation of SRF with IRC and PED in contrast to increased colocalization of IRC and PED. These morphological associations may contribute to our understanding of functional deficits in nAMD.
关键词： subretinal fluid,age-related macular degeneration,intraretinal cystoid fluid,optical coherence tomography,automated image analysis
更新于2025-09-10 09:29:36
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Repeatability, reproducibility and interocular difference in the assessments of optic nerve OCT in children– a Swedish population-based study
摘要： Background: The aim was, first, to collect normative data of the optic nerve head and the peripapillary retinal nerve fibre layer (RNFL) thickness assessed with Cirrus SD-OCT, in healthy children in a population-based study; second, using these data, to examine repeatability, reproducibility and the interocular difference. Methods: One-hundred and ten eyes from 57 children aged 6–15 born at term, were examined. Best-corrected visual acuity and refraction were assessed. Both eyes were examined and the interocular difference was calculated. Repeatability was calculated by one examiner performing three assessments. Thereafter, a second examiner repeated the assessments to calculate reproducibility. Results: Mean RNFL thickness was 99.2 (SD 8.8) μm, mean disc area 1.89 (SD 0.37) mm2 and mean rim area 1.52 (SD 0.26) mm2. No significant correlations with age, gender or refraction were found. Repeatability and reproducibility were good overall. There was interocular symmetry between the eyes. Conclusions: Normal values for optic nerve head and RNFL thickness assessed with Cirrus SD-OCT were gathered to obtain a normal material in children. High repeatability and reproducibility indicated reliability of assessments performed by different examiners on different occasions. Overall, good correlation between right and left eyes was found.
关键词： Children,Optical coherence tomography (OCT),Repeatability,Interocular difference,Normal values,Reproducibility
更新于2025-09-10 09:29:36
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High Resolution DEM Building with SAR Interferometry and High Resolution Optical Image
摘要： There have been many published articles describing Interferometry algorithms for DEM generation in different applications. The best uncertainty achieved in most of these articles is greater than ±1m calculating the elevation. Enabling scientists to gain experience with new techniques at low cost. Interferometry with Synthetic aperture radar (InSAR) is one of the best technique for measuring the altimetry surface, its different changes and degradation over time, and the characteristics detailed of the surface[9]. To take a better resolution of the surfaces, we propose our approach; it’s to merge the results of the interferometry and data from segmentation of an optical high resolution image. In this report we describe a procedure for hybridization of interferometry Algorithm (InSAR) and the use of geospatial data from the image segmentation, with Extraction of the building to calculate the zonal statistic parameter and mapping all segments comprising the highest elevations. This report is written in a step by step format to simplify the complicated steps described in the paper, with a focus on the Hybridization instead of the interferometry. The tests of this method were carried out on several sites, and showed good results.
关键词： co-registration,InSAR Interferometry,hybridization,Building High resolution,interferometric coherence,DEM Building
更新于2025-09-10 09:29:36
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Combination of High-Resolution Optical Coherence Tomography and Raman Spectroscopy for Improved Staging and Grading in Bladder Cancer
摘要： We present a combination of optical coherence tomography (OCT) and Raman spectroscopy (RS) for improved diagnosis and discrimination of different stages and grades of bladder cancer ex vivo by linking the complementary information provided by these two techniques. Bladder samples were obtained from biopsies dissected via transurethral resection of the bladder tumor (TURBT). As OCT provides structural information rapidly, it was used as a red-flag technology to scan the bladder wall for suspicious lesions with the ability to discriminate malignant tissue from healthy urothelium. Upon identification of degenerated tissue via OCT, RS was implemented to determine the molecular characteristics via point measurements at suspicious sites. Combining the complementary information of both modalities allows not only for staging, but also for differentiation of low-grade and high-grade cancer based on a multivariate statistical analysis. OCT was able to clearly differentiate between healthy and malignant tissue by tomogram inspection and achieved an accuracy of 71% in the staging of the tumor, from pTa to pT2, through texture analysis followed by k-nearest neighbor classification. RS yielded an accuracy of 93% in discriminating low-grade from high-grade lesions via principal component analysis followed by k-nearest neighbor classification. In this study, we show the potential of a multi-modal approach with OCT for fast pre-screening and staging of cancerous lesions followed by RS for enhanced discrimination of low-grade and high-grade bladder cancer in a non-destructive, label-free and non-invasive way.
关键词： principal component analysis (PCA),Raman spectroscopy (RS),k-nearest neighbor classification (kNN),bladder cancer,optical coherence tomography (OCT)
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 20th International Conference on e-Health Networking, Applications and Services (Healthcom) - Ostrava, Czech Republic (2018.9.17-2018.9.20)] 2018 IEEE 20th International Conference on e-Health Networking, Applications and Services (Healthcom) - Extraction and Analysis of RPE layer from OCT Images for Detection of Age Related Macular Degeneration
摘要： Age-related Macular Degeneration (AMD) is an eye disease which affects elderly people. Cholesterol deposits in central part of retina, known as macula, damages the photoreceptors present in a particular area of eye. AMD usually effects only central vision of patient. In medical field various imaging techniques are used for diagnosis of eye diseases. Optical Coherence Tomography (OCT) is a relatively newer technique that is found to be very useful in analyzing eyes. In this research, we used OCT images to automatically detect and classify AMD. First we extract the retinal layer known as Retinal Pigment Epithelium by utilizing Graph Theory Dynamic Programming technique, after successfully enhancing the quality of OCT image by using Wiener filter. We used a unique feature set consisting of features extracted from difference signal of RPE and Inner Segment Outer Segment layer of RPE. Feature set includes approximation coefficient, entropy and spectrum energy of the resulting difference signal. Support Vector Machine classifier was used to classify AMD affected and normal image. The developed system gives an accuracy of 95% for AMD detection.
关键词： Optical Coherence Tomography,Age-Related Macular Degeneration,Computer Aided Diagnostic
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Multi-Baseline Insar Experiments in Natural Scenarios with Tandem-X Staring Spotlight Data
摘要： In this paper, the potential of very-high resolution multi-baseline (MB) SAR images acquired in Staring Spotlight mode and Pursuit Monostatic configuration of the TanDEM-X mission during the Science Phase will be evaluated for series of InSAR acquisitions over a natural scene. In particular, this work focuses on the use of very-high resolution and baseline diversity to help to characterize X-band backscattering in the 3-D space, e.g. in terms of penetration in forest scenarios. At the same time, the application of classical MB InSAR techniques to identify geometry-related issues such as layover in (mainly) surface areas with rough topography is preliminarily addressed.
关键词： SAR Tomography (TomoSAR),Synthetic Aperture Radar (SAR),InSAR coherence,decorrelation
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Linking Sar Tomography and Polarization Coherence Tomography in Forest Scenarios
摘要： Space borne implementations of SAR tomography (TomoSAR) for forest volumes are particularly challenging, as the estimation of 3D reflectivity has to be carried out relying on a small number of acquisitions (or interferometric coherences) and/or non-uniform baseline distributions. A way to overcome this shortcoming is to approximate the reflectivity profile by a weighted series of functions, as for example proposed in the case of Polarization Coherence Tomography (PCT). In this case the individual weights can be estimated from a rather small number of interferometric coherences. In this work, we investigate how conventional TomoSAR can be linked to PCT by means of a suitable function basis. A real data analysis is carried out on TomoSAR reflectivity profiles obtained from a data set acquired in an airborne campaign over a temperate forest.
关键词： SAR tomography,polarization coherence tomography,forests
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Polarimetric Coherence Optimization as a Multidimensional Polarimetric SAR Signal Processing Tool
摘要： This paper summarizes a set of studies led on the topic of polarimetric coherence optimization for the coherent processing of stacks of polarimetric SAR images. It is shown that coherence maximization may be understood differently depending on the application at hand. Extracting polarimetric coherent signals embedded in noise or in a severe background requires to use polarimetric diversity as a supplementary mean for discovering organized speckles patterns, whereas classical MB-PolInSAR coherence optimization gives more importance to the polarimetric scattering mechanisms that extremize coherence values. This paper reviews different techniques able to cope with an arbitrary number of images and that are characterized by their low degree of computational complexity, conferred by the favored use of analytical solutions. The usefulness of these techniques is demonstrated using various kinds of applications to real spaceborne and airborne datasets.
关键词： Polarimetric SAR Tomography (PolTomSAR),PolSAR,coherence optimization,coherent target detection,3-D imaging
更新于2025-09-09 09:28:46
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Efficacy of intravitreal aflibercept monotherapy in retinopathy of prematurity evaluated by periodic fluorescence angiography and optical coherence tomography
摘要： Purpose To evaluate the efficacy of intravitreal aflibercept (IVA) in vascular and macular maturation in neonates with type 1 retinopathy of prematurity (ROP) and aggressive posterior retinopathy of prematurity (APROP). Materials and methods Thirty-six eyes of 18 patients with type 1 ROP or APROP in zone I or posterior zone II were enrolled in our study. At baseline, only fluorescein angiography (FA) was performed. After IVA injection, both FA and optical coherence tomography (OCT) were performed after 6.8 ± 0.8 (range 6–8) and 19 ± 0.9 (range 18–20) weeks to follow vascular and macular changes. Results Both diffuse flat neovascularization with leakage and abnormal vascular branching at the small arteriolar level were detected in all eyes (100%) at baseline FA. Regression of the disease was observed in 34 eyes (94.4%) in the first week with binocular indirect ophthalmoscopy. Early unresponsiveness in remaining two eyes of an infant required an IVA re-treatment. Late reactivation was detected only in 19.4% of eyes, none of which required treatment during 12 months of follow-up. The most common feature after IVA injection was abnormal branching at capillary level, which was noted in 100% in the first post-injection FA and 50.0% of all eyes in the second FA. Meanwhile, the end limit of vascularization was observed in zone III in 83.3% of eyes. No vascular abnormality was also detected in 27.3% of eyes. The OCT examination at a mean postmenstrual age of 43.4 weeks revealed cystoid macular changes in four eyes of two infants (11.1%), normal foveal contour in 30 eyes of 15 infants (83.3%) and matured ellipsoid zone at the foveal center in 28 eyes of 14 infants (77.8%). Macular maturation was complete in all eyes in the last OCT analyses. Conclusion Intravitreal aflibercept monotherapy has been an effective treatment in type I ROP and APROP with much lower early and late re-treatment rates because of early unresponsiveness and late reactivation, respectively. In most of the eyes, rapid vascular outgrowth beyond zone III together with normal macular maturation was observed more precisely by periodic FA and OCT.
关键词： Fluorescein angiography,Retinopathy of prematurity,Optical coherence tomography,Aflibercept
更新于2025-09-09 09:28:46
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Assessment of Schlemm’s canal in acute primary angle closure: an anterior segment optical coherence tomography study
摘要： Purpose To image and quantitatively evaluate the Schlemm’s canal (SC) dimensions in the eyes with acute primary angle closure (APAC) with anterior segment optical coherence tomography (AS-OCT), and compare it with the SC measurements taken after the control of intraocular pressure (IOP) and in the normal age-matched controls. Materials and methods Seventeen eyes of 14 patients with the newly diagnosed APAC and 59 age-matched normal subjects underwent AS-OCT to image SC. SC cross-sectional area, SC meridional and coronal diameters were measured in the temporal and nasal regions at 3 and 9 o’clock position. After laser iridotomy and control of the IOP, all SC parameters were measured again at a week later, in APAC eyes. the SC Intrasession intraobserver reliability of measurements was assessed with intraclass correlation coef?cient. Results Mean SC-SCA (10,600 ± 2691 lm2), SC meridional (682 ± 125 lm) and coronal diameters (21.2 ± 8.2 lm) showed a signi?cant increase in the APAC eyes at presentation, when compared to the SC parameters measured at a week later (6499 ± 1754 lm2, 450 ± 169 lm and 15.75 ± 8.6 lm, p = \ 0.0001, \ 0.0001 and 0.01, respectively) and in the normal controls (7192 ± 1022 lm2, 499.2 ± 179.8 lm, p = 0.02, \ 0.0001, 0.01, respectively). There was no difference in the measured SC parameters between the normal controls and APAC eyes, when the parameters were measured at a week, after resolution of the acute attack (all p [ 0.05). Conclusion A signi?cant expansion of SC was observed in the APAC eyes at presentation, when compared to the normal controls and after the acute attack resolved. SC parameters may provide a useful research tool for evaluating morphological changes in the SC in APAC eyes, during an acute attack.
关键词： Schlemm’s canal,Anterior segment optical coherence tomography,Acute primary angle closure
更新于2025-09-09 09:28:46