1. Christian Simader

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    1. Mentioned In 31 Articles

    2. Reproducibility of Retinal Thickness Measurements across Spectral-Domain Optical Coherence Tomography Devices using Iowa Reference Algorithm

      Reproducibility of Retinal Thickness Measurements across Spectral-Domain Optical Coherence Tomography Devices using Iowa Reference Algorithm
      PURPOSE: Establishing and obtaining consistent quantitative indices of retinal thickness from a variety of clinically used Spectral-Domain Optical Coherence Tomography scanners. DESIGN: Retinal images from five Spectral-Domain Optical Coherence Tomography scanners were used to determine total retinal thickness with scanner-specific correction factors establishing consistency of thickness measurement across devices. PARTICIPANTS: 55 Fovea-centered Spectral-Domain Optical Coherence Tomography volumes from eleven subjects were analyzed, obtained from Cirrus HD-OCT, RS-3000, Heidelberg Spectralis, RTVue ...
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    3. Multivendor Spectral-Domain Optical Coherence Tomography Dataset, Observer Annotation Performance Evaluation, and Standardized Evaluation Framework for Intraretinal Cystoid Fluid Segmentation

      Multivendor Spectral-Domain Optical Coherence Tomography Dataset, Observer Annotation Performance Evaluation, and Standardized Evaluation Framework for Intraretinal Cystoid Fluid Segmentation
      Development of image analysis and machine learning methods for segmentation of clinically significant pathology in retinal spectral-domain optical coherence tomography (SD-OCT), used in disease detection and prediction, is limited due to the availability of expertly annotated reference data. Retinal segmentation methods use datasets that either are not publicly available, come from only one device, or use different evaluation methodologies making them difficult to compare. Thus we present and evaluate a ...
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    4. Improve synthetic retinal OCT images with present of pathologies and textural information

      Improve synthetic retinal OCT images with present of pathologies and textural information
      The lack of noise free Optical Coherence Tomography (OCT) images makes it challenging to quantitatively evaluate performance of image processing methods such as denoising methods. The synthetic noise free OCT images are needed to evaluate performance of image processing methods. The current synthetic methods fail to generate synthetic images that represent real OCT images with present of pathologies. They cannot correctly imitate real OCT data due to a tendency to ...
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    5. Geodesic denoising for optical coherence tomography images

      Geodesic denoising for optical coherence tomography images
      Optical coherence tomography (OCT) is an optical signal acquisition method capturing micrometer resolution, cross-sectional three-dimensional images. OCT images are used widely in ophthalmology to diagnose and monitor retinal diseases such as age-related macular degeneration (AMD) and Glaucoma. While OCT allows the visualization of retinal structures such as vessels and retinal layers, image quality and contrast is reduced by speckle noise, obfuscating small, low intensity structures and structural boundaries. Existing denoising ...
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    6. A Novel Benchmark Model for Intelligent Annotation of Spectral-Domain Optical Coherence Tomography Scans Using the Example of Cyst Annotation

      A Novel Benchmark Model for Intelligent Annotation of Spectral-Domain Optical Coherence Tomography Scans Using the Example of Cyst Annotation
      Background and Objectives: The lack of benchmark data in computational ophthalmology contributes to the challenging task of applying disease assessment and evaluate performance of machine learning based methods on retinal spectral domain optical coherence tomography (SD-OCT) scans. Presented here is a general framework for constructing a benchmark dataset for retinal image processing tasks such as cyst, vessel, and subretinal fluid segmentation and as a result, a benchmark dataset for cyst ...
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    7. Choroidal thickness maps from spectral domain and swept source optical coherence tomography: algorithmic versus ground truth annotation

      Choroidal thickness maps from spectral domain and swept source optical coherence tomography: algorithmic versus ground truth annotation
      Background/aims The purpose of the study was to create a standardised protocol for choroidal thickness measurements and to determine whether choroidal thickness measurements made on images obtained by spectral domain optical coherence tomography (SD-OCT) and swept source (SS-) OCT from patients with healthy retina are interchangeable when performed manually or with an automatic algorithm. Methods 36 grid cell measurements for choroidal thickness for each volumetric scan were obtained, which ...
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    8. Choroidal line scan measurements in swept-source optical coherence tomography as surrogates for volumetric thickness assessment - American Journal of Ophthalmology

      Choroidal line scan measurements in swept-source optical coherence tomography as surrogates for volumetric thickness assessment - American Journal of Ophthalmology
      Purpose To compare choroidal thickness of different areas on swept-source optical coherence tomography (SS-OCT) line and cube scans for their interchangeable use. Design Validity analysis. Methods SS-OCT line and cube scans were obtained from 21 patients with various choroidal thicknesses. Subfoveal centerpoint choroidal thickness, mean central millimeter choroidal thickness and mean 6-mm area choroidal thicknesses were obtained from both eyes by two independent graders in a reading center setting. Cross-correlations ...
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    9. Differentiation of Diabetic Macular Edema From Pseudophakic Cystoid Macular Edema by Spectral-Domain Optical Coherence Tomography

      Differentiation of Diabetic Macular Edema From Pseudophakic Cystoid Macular Edema by Spectral-Domain Optical Coherence Tomography
      Purpose : To differentiate diabetic macular edema (DME) from pseudophakic cystoid macular edema (PCME) based solely on spectral-domain optical coherence tomography (SD-OCT). Methods : This cross-sectional study included 134 participants: 49 with PCME, 60 with DME, and 25 with diabetic retinopathy (DR) and ME after cataract surgery. First, two unmasked experts classified the 25 DR patients after cataract surgery as either DME, PCME, or mixed-pattern based on SD-OCT and color-fundus photography. Then ...
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    10. Automated retinal fovea type distinction in spectral-domain optical coherence tomography of retinal vein occlusion

      Automated retinal fovea type distinction in spectral-domain optical coherence tomography of retinal vein occlusion
      ...ct is permitted for personal use only. Jing Wu ; Sebastian M. Waldstein ; Bianca S. Gerendas ; Georg Langs ; Christian Simader ; Ursula Schmidt-Erfurth; Automated retinal fovea type distinction in spectral-domain optica...
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    11. Comparison of penetration depth in choroidal imaging using swept source vs spectral domain optical coherence tomography

      Comparison of penetration depth in choroidal imaging using swept source vs spectral domain optical coherence tomography
      Purpose To compare signal penetration depth and deep structure-visualization of swept source (SS) and spectral domain (SD)-optical coherence tomography (OCT) with and without enhanced depth imaging (EDI) and B-scan averaging modes. Methods Volume scans were obtained from 20 eyes of healthy volunteers by DRI OCT-1, Spectralis using EDI and B-scan averaging, and Cirrus HD-OCT. The signal penetration depth was measured as the distance between the retinal pigment epithelium and ...
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    12. Quantitative comparison of macular segmentation performance using identical retinal regions across multiple spectral-domain optical coherence tomography instruments

      Quantitative comparison of macular segmentation performance using identical retinal regions across multiple spectral-domain optical coherence tomography instruments
      ...mage Analysis, Vienna Reading Center, Medical University of Vienna, Vienna, Austria 1. Correspondence to Dr Christian Simader, Department of Ophthalmology, Christian-Doppler-Laboratory for Ophthalmic Image Analysis, Wa...
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    13. Motion Artefact Correction in Retinal Optical Coherence Tomography Using Local Symmetry

      Motion Artefact Correction in Retinal Optical Coherence Tomography Using Local Symmetry
      Patient movements during the acquisition of SD-OCT scans create substantial motion artefacts in the volumetric data that hinder registration and 3D analysis and can be mistaken for pathologies. In this paper we propose a method to correct these artefacts using a single volume scan while still retaining the overall shape of the retina. The method was quantitatively validated using a set of synthetic SD-OCT volumes and qualitatively by a group ...
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    14. Stable Registration of Pathological 3D SD-OCT Scans using Retinal Vessels

      Stable Registration of Pathological 3D SD-OCT Scans using Retinal Vessels
      We propose a multiple scanner vendor registration method for pathological retinal 3D spectral domain optical coherence tomography volumes based on Myronenkos Coherent Point Drift and our automated vessel shadow segmentation. Coherent point drift is applied to the segmented retinal vessel point sets used as landmarks to generate the registration parameters required. In contrast to other registration methods, our solution incorporates a landmark detection and extraction method that specifically limits the ...
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    15. Three-dimensional automated choroidal volume assessment on standard spectral-domain optical coherence tomography and correlation with the level of diabetic macular edema

      Three-dimensional automated choroidal volume assessment on standard spectral-domain optical coherence tomography and correlation with the level of diabetic macular edema
      ...nalysis, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria , Christian Simader x Christian Simader Search for articles by this author Affiliations * Vienna Reading Center, Department of O...
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    16. DIFFERENTIAL DIAGNOSIS OF MACULAR EDEMA OF DIFFERENT PATHOPHYSIOLOGIC ORIGINS BY SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

      DIFFERENTIAL DIAGNOSIS OF MACULAR EDEMA OF DIFFERENT PATHOPHYSIOLOGIC ORIGINS BY SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY
      Purpose: To develop a classification approach based solely on spectral domain optical coherence tomography to differentiate macular edema (ME) of different disease entities and to determine underlying pathology. Methods: A cross-sectional study including 153 participants: 27 with Irvine-Gass, 31 with uveitic ME, 24 with ME after branch retinal vein occlusion, 13 with central retinal vein occlusion, 44 with diabetic ME, and 14 controls. Spectral domain optical coherence tomography was graded ...
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    17. 1-15 of 31 1 2 »
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  2. About Christian Simader

    Christian Simader

    Christian Simader is the head of the Vienna Reading Center (VRC) at the Department of Radiology at the Medical University of Vienna