1. Articles from Danuta M. Sampson

    1-9 of 9
    1. Towards standardizing retinal optical coherence tomography angiography: a review

      Towards standardizing retinal optical coherence tomography angiography: a review

      The visualization and assessment of retinal microvasculature are important in the study, diagnosis, monitoring, and guidance of treatment of ocular and systemic diseases. With the introduction of optical coherence tomography angiography (OCTA), it has become possible to visualize the retinal microvasculature volumetrically and without a contrast agent. Many lab-based and commercial clinical instruments, imaging protocols and data analysis methods and metrics, have been applied, often inconsistently, resulting in a confusing picture that represents a major barrier to progress in applying OCTA to reduce the burden of disease. Open data and software sharing, and cross-comparison and pooling of data from different ...

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    2. 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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    3. Detection of localized pulsatile motion in cutaneous microcirculation by speckle decorrelation optical coherence tomography angiography

      Detection of localized pulsatile motion in cutaneous microcirculation by speckle decorrelation optical coherence tomography angiography

      Significance: Pulsatility is a vital characteristic of the cardiovascular system. Characterization of the pulsatility pattern locally in the peripheral microvasculature is currently not readily available and would provide an additional source of information, which may prove important in understanding the pathophysiology of arterial stiffening, vascular ageing, and their linkage with cardiovascular disease development. Aim: We aim to confirm the suitability of speckle decorrelation optical coherence tomography angiography (OCTA) under various noncontact/contact scanning protocols for the visualization of pulsatility patterns in vessel-free tissue and in the microvasculature of peripheral human skin. Results: Results from five healthy subjects show distinct pulsatile ...

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    4. RTVue XR AngioVue Optical Coherence Tomography Angiography Software Upgrade Impacts on Retinal Thickness and Vessel Density Measurements

      RTVue XR AngioVue Optical Coherence Tomography Angiography Software Upgrade Impacts on Retinal Thickness and Vessel Density Measurements

      Purpose : To determine the impact of an AngioVue software upgrade on total retinal thickness (RT) and inner retinal vessel density (VD) measurements derived from optical coherence tomography angiography (OCTA). Methods : Optovue OCTA images (3 × 3 mm) from 126 individuals (105 healthy eyes and 72 eyes with retinal disease) were acquired before an upgrade of the AngioVue software, which resulted in an inward shift of the outer boundary of the inner retinal vessels and improved Bruch's membrane segmentation. Total RT and inner retinal VD values were extracted before and after the software upgrade for comparison. Bias and limits of agreement ...

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    5. In vivo brain imaging with multimodal optical coherence microscopy in a mouse model of thromboembolic photochemical stroke

      In vivo brain imaging with multimodal optical coherence microscopy in a mouse model of thromboembolic photochemical stroke

      We used a new multimodal imaging system that combines optical coherence microscopy and brightfield microscopy. Using this in vivo brain monitoring approach and cranial window implantation, we three-dimensionally visualized the vascular network during thrombosis, with high temporal (18 s) and spatial (axial, 2.5  μm; lateral, 2.2  μm) resolution. We used a modified mouse model of photochemical thromboembolic stroke in order to more accurately parallel human stroke. Specifically, we applied green laser illumination to focally occlude a branch of the middle cerebral artery. Despite the recanalization of the superficial arteries at 24 h after stroke, no blood flow was ...

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    6. Clinical validation of the RTVue optical coherence tomography angiography image quality indicators

      Clinical validation of the RTVue optical coherence tomography angiography image quality indicators

      Importance All automated image quality indicators for en face optical coherence tomography angiography (OCTA) images require gold standard validation for determining optimal thresholds. Background A manual grading system (gold standard) for OCTA images was validated and compared to two automated image quality indicators: signal strength index (SSI) and scan quality index (SQI) generated by different software versions of the Optovue OCTA device. Design Retrospective cross‐sectional study. Participants 52 eyes of 52 healthy individual and 77 eyes of 51 patients with retinal vascular diseases. Methods 129 OCTA images of the superficial vascular plexus were graded manually by 3 independent examiners ...

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    7. Posterior Choroidal Stroma Reduces Accuracy of Automated Segmentation of Outer Choroidal Boundary in Swept Source Optical Coherence Tomography

      Posterior Choroidal Stroma Reduces Accuracy of Automated Segmentation of Outer Choroidal Boundary in Swept Source Optical Coherence Tomography

      Purpose : To determine the influence of choroidal boundary morphology on the accuracy of automated measurements of subfoveal choroidal thickness (SFCT) in swept source optical coherence tomography (SSOCT). Methods : A retrospective image analysis of foveal-centered horizontal line scans from normal and diseased eyes using the Topcon DRI OCT-1 Atlantis SSOCT was conducted. Subfoveal choroid-scleral junction (CSJ) and retina-choroidal junction (RCJ) morphologies were graded by two observers. Automated SFCT (A-SFCT) was compared with manual SFCT (M-SFCT) measurements from Bruch's membrane to the posterior limits of choroidal vessel, hyperreflective stroma, and hyporeflective lamina fusca. Agreement in boundary grading was assessed by Cohen ...

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    8. Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Purpose : To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA). Methods : Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated. Results : Forty subjects were enrolled and the median (range) age of the ...

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    9. Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging

      Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging

      Purpose To present en face optical coherence tomography (OCT) images generated by graph-search theory algorithm-based custom software and examine correlation with other imaging modalities. Methods En face OCT images derived from high density OCT volumetric scans of 3 healthy subjects and 4 patients using a custom algorithm (graph-search theory) and commercial software (Heidelberg Eye Explorer software (Heidelberg Engineering)) were compared and correlated with near infrared reflectance, fundus autofluorescence, adaptive optics flood-illumination ophthalmoscopy (AO-FIO) and microperimetry. Results Commercial software was unable to generate accurate en face OCT images in eyes with retinal pigment epithelium (RPE) pathology due to segmentation error at ...

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    1-9 of 9
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    1. (8 articles) University of Western Australia
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    Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography Posterior Choroidal Stroma Reduces Accuracy of Automated Segmentation of Outer Choroidal Boundary in Swept Source Optical Coherence Tomography Clinical validation of the RTVue optical coherence tomography angiography image quality indicators In vivo brain imaging with multimodal optical coherence microscopy in a mouse model of thromboembolic photochemical stroke RTVue XR AngioVue Optical Coherence Tomography Angiography Software Upgrade Impacts on Retinal Thickness and Vessel Density Measurements Detection of localized pulsatile motion in cutaneous microcirculation by speckle decorrelation optical coherence tomography angiography OCTAVA: An open-source toolbox for quantitative analysis of optical coherence tomography angiography images Towards standardizing retinal optical coherence tomography angiography: a review New insights from non-invasive imaging: from prospection of skin photodamages to training with mobile application Short-sighted woman assumes debilitating headaches mean she needs new glasses but discovers she has multiple sclerosis Shedding light on the impact of microplastics on lentil seedling growth