1. Articles from Zhihong Hu

    1-12 of 12
    1. Automated Retinal Layer Segmentation Using Graph-based Algorithm Incorporating Deep-learning-derived Information

      Automated Retinal Layer Segmentation Using Graph-based Algorithm Incorporating Deep-learning-derived Information

      Regular drusen, an accumulation of material below the retinal pigment epithelium (RPE), have long been established as a hallmark early feature of nonneovascular age-related macular degeneration (AMD). Advances in imaging have expanded the phenotype of AMD to include another extracellular deposit, reticular pseudodrusen (RPD) (also termed subretinal drusenoid deposits, SDD), which are located above the RPE. We developed an approach to automatically segment retinal layers associated with regular drusen and RPD in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a shortest-path algorithm enhanced with probability maps generated through a fully convolutional neural network was used to segment ...

      Read Full Article
    2. Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Historically, regular drusen and geographic atrophy (GA) have been recognized as the hallmarks of nonneovascular age-related macular degeneration (AMD). Recent imaging developments have revealed another distinct nonneovascular AMD phenotype, reticular pseudodrusen (RPD). We develop an approach to semiautomatically quantify retinal surfaces associated with various AMD lesions (i.e., regular drusen, RPD, and GA) in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a graph-based algorithm was used to segment multiple retinal layers in SD-OCT volumes. Varying surface feasibility constraints based on the presegmentation were applied on the double-surface graph search to refine the surface segmentation. The thicknesses of ...

      Read Full Article
    3. Comparison of Retinal Layer Intensity Profiles From Different OCT Devices

      Comparison of Retinal Layer Intensity Profiles From Different OCT Devices

      BACKGROUND AND OBJECTIVE: The purpose of this study is to use automated multiple retinal layer segmentation to compare retinal layer intensity profiles between different spectral-domain optical coherence tomography (SD-OCT) devices with and without normalization. PATIENTS AND METHODS: A graph-based multistage segmentation approach was used to identify 11 boundaries in horizontal SD-OCT B-scans passing through the foveal center. Four acquisition protocols from two different SD-OCT devices were applied on 34 eyes from 17 healthy participants. The mean intensity of the 11 layers was compared within each device and between the two devices. In addition, the intensity of the various layers was ...

      Read Full Article
    4. Segmentation of the Geographic Atrophy in Spectral-domain Optical Coherence Tomography and Fundus Autofluorescene Images

      Segmentation of the Geographic Atrophy in Spectral-domain Optical Coherence Tomography and Fundus Autofluorescene Images

      Purpose: The purpose is to develop a geographic atrophy segmentation approach in both spectral-domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) images and compare the segmentation performance. Methods: To identify GA in SD-OCT images, three surfaces were first segmented using graph search. A 2-D partial OCT projection image was created from the segmented choroid layer. A level-set approach was applied to segment GA in the partial OCT projection image. The algorithm was also applied to FAF images. Twenty randomly chosen macular SD-OCT (Zeiss Cirrus) volumes and twenty corresponding FAF (Heidelberg Spectralis) images were obtained from twenty subjects with GA ...

      Read Full Article
    5. Multiple layer segmentation and analysis in three-dimensional spectral-domain optical coherence tomography volume scans

      Multiple layer segmentation and analysis in three-dimensional spectral-domain optical coherence tomography volume scans

      Spectral-domain optical coherence tomography (SD-OCT) is a three-dimensional imaging technique that allows direct visualization of retinal morphology and architecture. The various retinal layers may be affected differentially by various diseases. An automated graph search algorithm is developed to sequentially segment 11 retinal surfaces in SD-OCT volumes using a three-stage approach. In stage 1, the four most easily discernible and/or distinct surfaces are identified in four-times-downsampled images and are used as a priori information to limit the graph search for the other surfaces in stage 2. Eleven surfaces were then detected in two-times-downsampled images in stage 2, and refined in ...

      Read Full Article
    6. Automated multilayer segmentation and characterization in 3D spectral-domain optical coherence tomography images

      Automated multilayer segmentation and characterization in 3D spectral-domain optical coherence tomography images

      Spectral-domain optical coherence tomography (SD-OCT) is a 3-D imaging technique, allowing direct visualization of retinal morphology and architecture. The various layers of the retina may be affected differentially by various diseases. In this study, an automated graph-based multilayer approach was developed to sequentially segment eleven retinal surfaces including the inner retinal bands to the outer retinal bands in normal SD-OCT volume scans at three different stages. For stage 1, the four most detectable and/or distinct surfaces were identified in the four-times-downsampled images and were used as a priori positional information to limit the graph search for other surfaces at ...

      Read Full Article
    7. Semiautomated Segmentation of the Choroid in Spectral-domain Optical Coherence Tomography Volume Scans

      Semiautomated Segmentation of the Choroid in Spectral-domain Optical Coherence Tomography Volume Scans

      Purpose: Changes in the choroid, in particular its thickness, are believed to be of importance in the pathophysiology of a number of retinal diseases. The purpose of this study is to adapt the graph search algorithm to semi-automatically identify the choroidal layer in spectral-domain optical coherence tomography (SD-OCT) volume scans and compare its performance to manual delineation. Methods: A graph-based multi-stage segmentation approach was used to identify the choroid, defined as the layer between the outer border of the retinal pigment epithelium (RPE) band and the choroid-sclera junction. Thirty randomly chosen macular SD-OCT (Heidelberg Spectralis) volumes were obtained from 20 ...

      Read Full Article
    8. Multimodal Retinal Vessel Segmentation from Spectral-Domain Optical Coherence Tomography and Fundus Photography

      Multimodal Retinal Vessel Segmentation from Spectral-Domain Optical Coherence Tomography and Fundus Photography

      Segmenting retinal vessels in optic nerve head (ONH) centered spectral-domain optical coherence tomography (SD-OCT) volumes is particularly challenging due to the projected neural canal opening (NCO) and relatively low visibility in the ONH center. Color fundus photographs provide a relatively high vessel contrast in the region inside the NCO, but have not been previously used to aid the SD-OCT vessel segmentation process. Thus, in this paper, we present two approaches for the segmentation of retinal vessels in SD-OCT volumes that each take advantage of complimentary information from fundus photographs. In the first approach (referred to as the registeredfundus vessel segmentation ...

      Read Full Article
    9. Automated multimodality concurrent classification for segmenting vessels in 3D spectral OCT and color fundus images

      Automated multimodality concurrent classification for segmenting vessels in 3D spectral OCT and color fundus images

      Segmenting vessels in spectral-domain optical coherence tomography (SD-OCT) volumes is particularly challenging in the region near and inside the neural canal opening (NCO). Furthermore, accurately segmenting them in color fundus photographs also presents a challenge near the projected NCO. However, both modalities also provide complementary information to help indicate vessels, such as a better NCO contrast from the NCO-aimed OCT projection image and a better vessel contrast inside the NCO from fundus photographs. We thus present a novel multimodal automated classification approach for simultaneously segmenting vessels in SD-OCT volumes and fundus photographs, with a particular focus on better segmenting vessels ...

      Read Full Article
    10. Automated Segmentation of 3-D Spectral OCT Retinal Blood Vessels by Neural Canal Opening False Positive Suppression

      Automated Segmentation of 3-D Spectral OCT Retinal Blood Vessels by Neural Canal Opening False Positive Suppression

      We present a method for automatically segmenting the blood vessels in optic nerve head (ONH) centered spectral-domain optical coherence tomography (SD-OCT) volumes, with a focus on the ability to segment the vessels in the region near the neural canal opening (NCO). The algorithm first pre-segments the NCO using a graph-theoretic approach. Oriented Gabor wavelets rotated around the center of the NCO are applied to extract features in a 2-D vessel-aimed projection image. Corresponding oriented NCO-based templates are utilized to help suppress the false positive tendency near the NCO boundary. The vessels are identified in a vessel-aimed projection image using a ...

      Read Full Article
    11. Automated Segmentation of Neural Canal Opening and Optic Cup in 3-D Spectral Optical Coherence Tomography Volumes of the Optic Nerve Head

      Automated Segmentation of Neural Canal Opening and Optic Cup in 3-D Spectral Optical Coherence Tomography Volumes of the Optic Nerve Head
      Purpose: To develop an automated approach for segmenting the neural canal opening (NCO) and cup at the level of retinal pigment epithelium (RPE)/Bruch's membrane (BM) complex in spectral-domain optical coherence tomography (SD-OCT) volumes. To investigate the correspondence and discrepancy of the NCO-based metrics and clinical disc margin on fundus photographs in glaucoma subjects. Methods: SD-OCT scans (CirrusTM HD-OCT) and corresponding stereo fundus photographs (Nidek 3Dx) of the optic nerve head (ONH) are obtained from 68 eyes of 34 patients with glaucoma or glaucoma suspicion. Manual planimetry is performed by three glaucoma experts to delineate a reference standard (RS ...
      Read Full Article
    12. Automated segmentation of the optic disc margin in 3-D optical coherence tomography images using a graph-theoretic approach

      Automated segmentation of the optic disc margin in 3-D optical coherence tomography images using a graph-theoretic approach

      The optic disc margin is of interest due to its use for detecting and managing glaucoma. We developed a method for segmenting the optic disc margin of the optic nerve head (ONH) in spectral-domain optical coherence tomography (OCT) images using a graph-theoretic approach. A small number of slices surrounding the Bruch's membrane opening (BMO) plane was taken and used for creating planar 2-D projection images. An edge-based cost function - more specifically, a signed edge-based term favoring a dark-to-bright transition in the vertical direction of polar projection images (corresponding to the radial direction in Cartesian coordinates) - was obtained. Information from ...

      Read Full Article
    1-12 of 12
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (12 articles) Zhihong Hu
    2. (8 articles) University of Iowa
    3. (7 articles) Srinivas R. Sadda
    4. (6 articles) University of Southern California
    5. (5 articles) Michael D. Abràmoff
    6. (4 articles) Mona K. Garvin
    7. (3 articles) Kyungmoo Lee
    8. (2 articles) UCLA
    9. (2 articles) Carl Zeiss Meditec
    10. (1 articles) Milan Sonka
    11. (1 articles) Universidade Federal de São Paulo
  3. Popular Articles

  4. Picture Gallery

    Automated segmentation of the optic disc margin in 3-D optical coherence tomography images using a graph-theoretic approach Automated Segmentation of Neural Canal Opening and Optic Cup in 3-D Spectral Optical Coherence Tomography Volumes of the Optic Nerve Head Automated Segmentation of 3-D Spectral OCT Retinal Blood Vessels by Neural Canal Opening False Positive Suppression Automated multimodality concurrent classification for segmenting vessels in 3D spectral OCT and color fundus images Multimodal Retinal Vessel Segmentation from Spectral-Domain Optical Coherence Tomography and Fundus Photography Semiautomated Segmentation of the Choroid in Spectral-domain Optical Coherence Tomography Volume Scans Automated multilayer segmentation and characterization in 3D spectral-domain optical coherence tomography images Multiple layer segmentation and analysis in three-dimensional spectral-domain optical coherence tomography volume scans Segmentation of the Geographic Atrophy in Spectral-domain Optical Coherence Tomography and Fundus Autofluorescene Images Comparison of Retinal Layer Intensity Profiles From Different OCT Devices Normal Reference Ranges of Optical Coherence Tomography Parameters in Children Optical coherence tomography angiography using the black-and-white pixel binarization histogram software: a new technique for evaluating healing of macular holes in two surgical techniques