1. Articles from Maximilian G. O. Gräfe

    1-6 of 6
    1. In Vivo 3D Determination of Peripapillary Scleral and Retinal Layer Architecture Using Polarization-Sensitive Optical Coherence Tomography

      In Vivo 3D Determination of Peripapillary Scleral and Retinal Layer Architecture Using Polarization-Sensitive Optical Coherence Tomography

      Purpose : The purpose of this paper was to determine the architecture of the collagen fibers of the peripapillary sclera, the retinal nerve fiber layer (RNFL), and Henle's fiber layer in vivo in 3D using polarization-sensitive optical coherence tomography (PS-OCT). Methods : Seven healthy volunteers were imaged with our in-house built PS-OCT system. PS-OCT imaging included intensity, local phase retardation, relative optic axis, and optic axis uniformity (OAxU). Differential Mueller matrix calculus was used for the first time in ocular tissues to visualize local orientations that varied with depth, incorporating a correction method for the fiber orientation in preceding layers. Results ...

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    2. Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography

      Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography

      Purpose : Subretinal fibrosis (SRFib) is an important cause of permanent loss-of-vision diseases with submacular neovascularization, but a reliable diagnostic method is currently missing. This study uses polarization-sensitive optical coherence tomography (PS-OCT) to detect SRFib within retinal lesions by measurement of its birefringent collagen fibers. Methods : Twenty-five patients were enrolled with retinal pathology in one or both eyes containing (1) suspected SRFib, (2) lesions suspected not to be fibrotic, or (3) lesions with doubtful presence of SRFib. All eyes were evaluated for SRFIb using conventional diagnostics by three retinal specialists. PS-OCT images were visually evaluated for SRFib based on cumulative phase ...

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    3. Optical coherence tomography velocimetry based on decorrelation estimation of phasor pair ratios (DEPPAIR)

      Optical coherence tomography velocimetry based on decorrelation estimation of phasor pair ratios (DEPPAIR)

      Quantitative velocity estimations in optical coherence tomography requires the estimation of the axial and lateral flow components. Optical coherence tomography measures the depth resolved complex field reflected from a sample. While the axial velocity component can be determined from the Doppler shift or phase shift between a pair of consecutive measurements at the same location, the estimation of the lateral component for in vivo applications is still challenging. One approach to determine lateral velocity is multiple simultaneous measurements at different angles. In another approach the lateral component can be retrieved through repeated measurements at (nearly) the same location by an ...

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    4. Optic axis uniformity as a metric to improve the contrast of birefringent structures and analyze the retinal nerve fiber layer in polarization-sensitive optical coherence tomography

      Optic axis uniformity as a metric to improve the contrast of birefringent structures and analyze the retinal nerve fiber layer in polarization-sensitive optical coherence tomography

      A new metric is used to improve the contrast of birefringent structures in biological tissue using polarization-sensitive optical coherence tomography. This metric, optic axis uniformity (OAxU), is based on the optic axis of birefringence and quantifies the uniformity of the optic axis direction. OAxU provides surprisingly strong contrast for fibrous structures such as muscle and the retinal nerve fiber layer (RNFL). We used OAxU for automatic segmentation of the RNFL in human eyes. From the segmentation, en face images of RNFL thickness and RNFL birefringence were created. The measured birefringence values are consistent with earlier reports.

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    5. In vivo multifunctional optical coherence tomography at the periphery of the lungs

      In vivo multifunctional optical coherence tomography at the periphery of the lungs

      Remodeling of tissue, such as airway smooth muscle (ASM) and extracellular matrix, is considered a key feature of airways disease. No clinically accepted diagnostic method is currently available to assess airway remodeling or the effect of treatment modalities such as bronchial thermoplasty in asthma, other than invasive airway biopsies. Optical coherence tomography (OCT) generates cross-sectional, near-histological images of airway segments and enables identification and quantification of airway wall layers based on light scattering properties only. In this study, we used a custom motorized OCT probe that combines standard and polarization sensitive OCT (PS-OCT) to visualize birefringent tissue in vivo in ...

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    6. Precision analysis and optimization in phase decorrelation OCT velocimetry

      Precision analysis and optimization in phase decorrelation OCT velocimetry

      Quantitative flow velocimetry in Optical Coherence Tomography is used to determine both the axial and lateral flow component at the level of individual voxels. The lateral flow is determined by analyzing the statistical properties of reflected electro-magnetic fields for repeated measurements at (nearly) the same location. The precision or statistical fluctuation of the quantitative velocity estimation depends on the number of repeated measurements and the method to determine quantitative flow velocity. In this paper, both a method to determine quantitative flow velocity and a model for the prediction of the statistical fluctuations of velocity estimations are developed to analyze and ...

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    1-6 of 6
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  2. Topics in the News

    1. (6 articles) VU University Amsterdam
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    Precision analysis and optimization in phase decorrelation OCT velocimetry In vivo multifunctional optical coherence tomography at the periphery of the lungs Optic axis uniformity as a metric to improve the contrast of birefringent structures and analyze the retinal nerve fiber layer in polarization-sensitive optical coherence tomography Optical coherence tomography velocimetry based on decorrelation estimation of phasor pair ratios (DEPPAIR) Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography In Vivo 3D Determination of Peripapillary Scleral and Retinal Layer Architecture Using Polarization-Sensitive Optical Coherence Tomography Non-invasive diagnosis of acquired lymphangiectases using optical coherence tomography Depth-resolved investigation of multiple optical properties and wrinkle morphology in eye-corner areas with multi-contrast Jones matrix optical coherence tomography Lipemia Retinalis: Hyperreflective Vascular Changes, Detected by Optical Coherence Tomography Enhanced Depth Imaging Optical Coherence Tomography Technology Reveals a Significant Association Between Optic Nerve Drusen Anterior Displacement and Retinal Nerve Fiber Layer Thinning Over Time Comparison of Peripapillary Vessel Density of Acute Nonarteritic Anterior Ischemic Optic Neuropathy and Other Optic Neuropathies With Disc Swelling Using Optical Coherence Tomography Angiography: A Pilot Study Optical Coherence Tomography Angiography Characteristics and Predictors of Visual Outcomes in Patients with Acute and Chronic Nonarteritic Anterior Ischemic Optic Neuropathy