Chiu SJ, Li XT, Nicholas P, et al.. Automatic segmentation of seven retinal layers in SDOCT images congruent with expert manual segmentation

Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
Optics Express (Impact Factor: 3.49). 08/2010; 18(18):19413-28. DOI: 10.1364/OE.18.019413
Source: PubMed


Segmentation of anatomical and pathological structures in ophthalmic images is crucial for the diagnosis and study of ocular diseases. However, manual segmentation is often a time-consuming and subjective process. This paper presents an automatic approach for segmenting retinal layers in Spectral Domain Optical Coherence Tomography images using graph theory and dynamic programming. Results show that this method accurately segments eight retinal layer boundaries in normal adult eyes more closely to an expert grader as compared to a second expert grader.

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    • "Of these, the first task is relatively well posed because the RPE, defining the CIB, is significantly brighter than adjacent layers. Indeed, the gradient-based approach in various flavors has proven accurate not only in detecting CIB [22]–[28], but also in the related problem of detecting boundaries between successive retinal layers with well-defined brightness transition [33]– [36]. Accordingly, we shall also adopt a gradient-based approach for CIB detection. "
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    ABSTRACT: A variety of vision ailments are indicated by anomalies in the choroid layer of the posterior visual section. Consequently, choroidal thickness and volume measurements, usually performed by experts based on optical coherence tomography (OCT) images, have assumed diagnostic significance. Now, to save precious expert time, it has become imperative to develop automated methods. To this end, one requires choroid outer boundary (COB) detection as a crucial step, where difficulty arises as the COB divides the choroidal granularity and the scleral uniformity only notionally, without marked brightness variation. In this backdrop, we measure the structural dissimilarity between choroid and sclera by structural similarity (SSIM) index, and hence estimate the COB by thresholding. Subsequently, smooth COB estimates, mimicking manual delineation, are obtained using tensor voting. On five datasets, each consisting of 97 adult OCT B-scans, automated and manual segmentation results agree visually. We also demonstrate close statistical match (greater than 99.6% correlation) between choroidal thickness distributions obtained algorithmically and manually. Further, quantitative superiority of our method is established over existing results by respective factors of 27.67% and 76.04% in two quotient measures defined relative to observer repeatability. Finally, automated choroidal volume estimation, being attempted for the first time, also yields results in close agreement with that of manual methods.
    Full-text · Article · Nov 2015 · Computerized medical imaging and graphics: the official journal of the Computerized Medical Imaging Society
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    • "Within a given eye of an individual animal, thirty B-scans were averaged to reduce the speckle noise in the image, corresponding to lateral averaging over 10 lm. A semi-automated segmentation software developed at Duke University (Chiu et al., 2010; Lee et al., 2013) was used to calculate the thickness and average intensity of each layer. These measurements were made sequentially at the same eccentricity in the same animal over time, resulting in longitudinal data. "
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    ABSTRACT: Microglia dynamically prune synaptic contacts during development, and digest waste that accumulates in degeneration and aging. In many neurodegenerative diseases, microglial activation and phagocytosis gradually increase over months or years, with poorly defined initial triggering events. Here, we describe rapid retinal microglial activation in response to physiological light levels in a mouse model of photoreceptor degeneration that arises from defective rhodopsin deactivation and prolonged signaling. Activation, migration and proliferation of microglia proceeded along a well-defined time course apparent within 12h of light onset. Retinal imaging in vivo with optical coherence tomography (OCT) revealed dramatic increases in light-scattering from photoreceptors prior to the outer nuclear layer thinning classically used as a measure of retinal neurodegeneration. This model is valuable for mechanistic studies of microglial activation in a well-defined and optically accessible neural circuit, and for the development of novel methods for detecting early signs of pending neurodegeneration in vivo.
    Full-text · Article · Sep 2014 · Vision Research
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    • "We have previously demonstrated novel algorithms for pathology segmentation that may be applied to identify the rapid alterations that occur during surgical intervention [4], [39]. Automated segmentation of retinal layers has been previously described [40]. The application of similar algorithms could potentially be utilized for real-time surgical feedback on instrument-tissue proximity. "
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    ABSTRACT: Purpose To demonstrate key integrative advances in microscope-integrated intraoperative optical coherence tomography (iOCT) technology that will facilitate adoption and utilization during ophthalmic surgery. Methods We developed a second-generation prototype microscope-integrated iOCT system that interfaces directly with a standard ophthalmic surgical microscope. Novel features for improved design and functionality included improved profile and ergonomics, as well as a tunable lens system for optimized image quality and heads-up display (HUD) system for surgeon feedback. Novel material testing was performed for potential suitability for OCT-compatible instrumentation based on light scattering and transmission characteristics. Prototype surgical instruments were developed based on material testing and tested using the microscope-integrated iOCT system. Several surgical maneuvers were performed and imaged, and surgical motion visualization was evaluated with a unique scanning and image processing protocol. Results High-resolution images were successfully obtained with the microscope-integrated iOCT system with HUD feedback. Six semi-transparent materials were characterized to determine their attenuation coefficients and scatter density with an 830 nm OCT light source. Based on these optical properties, polycarbonate was selected as a material substrate for prototype instrument construction. A surgical pick, retinal forceps, and corneal needle were constructed with semi-transparent materials. Excellent visualization of both the underlying tissues and surgical instrument were achieved on OCT cross-section. Using model eyes, various surgical maneuvers were visualized, including membrane peeling, vessel manipulation, cannulation of the subretinal space, subretinal intraocular foreign body removal, and corneal penetration. Conclusions Significant iterative improvements in integrative technology related to iOCT and ophthalmic surgery are demonstrated.
    Full-text · Article · Aug 2014 · PLoS ONE
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