1. Articles from Utku Baran

    1-15 of 15
    1. Optical coherence tomography based microangiography provides an ability to longitudinally image arteriogenesis in vivo

      Optical coherence tomography based microangiography provides an ability to longitudinally image arteriogenesis in vivo

      Purpose : To perform an analysis of optical coherence tomography (OCT) abnormalities in patients with MEWDS, during the acute and recovery stages, using enhanced depth imaging-OCT (EDI-OCT). Methods : A retrospective case series of five patients with MEWDS was included. EDI-OCT imaging was evaluated to detect retinal and choroidal features. Results : In the acute phase, focal impairment of the ellipsoid zone and external limiting membrane, hyperreflective dots in the inner choroid, and full-thickness increase of the choroidal profile were observed in the affected eye; disappearance of these findings and restoration of the choroidal thickness ( p = 0.046) was appreciated in the recovery ...

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    2. Tail artifact removal in OCT angiography images of rodent cortex

      Tail artifact removal in OCT angiography images of rodent cortex

      Optical coherence tomography angiography (OCTA) is a surging non-invasive, label-free, in vivo volumetric imaging method, currently being translated to clinical ophthalmology and becoming popular in neuroscience. Despite its attractiveness, there is an inherent issue of using OCT angiograms for quantitative cerebrovascular studies: The dynamic scattering of moving erythrocytes within pial vasculature creates tail-like artifacts that shadow the capillary vessels in the deeper layers of cortex. This false flow effect is relatively benign for qualitative visualization purposes, but it might have a significant impact on quantitative interpretation of angiographic results. In this work, we propose a simple image processing method to ...

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    3. Automated segmentation and enhancement of optical coherence tomography-acquired images of rodent brain

      Automated segmentation and enhancement of optical coherence tomography-acquired images of rodent brain

      Background Optical coherence tomography (OCT) is a non-invasive optical imaging method that has proven useful in various fields such as ophthalmology, dermatology and neuroscience. In ophthalmology, significant progress has been made in retinal layer segmentation and enhancement of OCT images. There are also segmentation algorithms to separate epidermal and dermal layers in OCT-acquired images of human skin. New Method We describe simple image processing methods that allow automatic segmentation and enhancement of OCT images of rodent brain. Results We demonstrate the effectiveness of the proposed methods for OCT-based microangiography (OMAG) and tissue injury mapping (TIM) of mouse cerebral cortex. The ...

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    4. Intervolume analysis to achieve four-dimensional optical microangiography for observation of dynamic blood flow

      Intervolume analysis to achieve four-dimensional optical microangiography for observation of dynamic blood flow

      We demonstrate in vivo volumetric optical microangiography at ∼ 200    volumes / s ∼200  volumes/s by the use of 1.6 MHz Fourier domain mode-locking swept source optical coherence tomography and an effective 36 kHz microelectromechanical system (MEMS) scanner. We propose an intervolume analysis strategy to contrast the dynamic blood flow signal from the static tissue background. The proposed system is demonstrated by imaging cerebral blood flow in mice in vivo . For the first time, imaging speed, sensitivity, and temporal resolution become possible for a direct four-dimensional observation of microcirculations within live body parts.

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    5. Video-rate volumetric optical coherence tomography-based microangiography

      Video-rate volumetric optical coherence tomography-based microangiography

      Video-rate volumetric optical coherence tomography (vOCT) is relatively young in the field of OCT imaging but has great potential in biomedical applications. Due to the recent development of the MHz range swept laser sources, vOCT has started to gain attention in the community. Here, we report the first in vivo video-rate volumetric OCT-based microangiography (vOMAG) system by integrating an 18-kHz resonant microelectromechanical system (MEMS) mirror with a 1.6-MHz FDML swept source operating at ∼ 1.3    μ m ∼1.3  μm wavelength. Because the MEMS scanner can offer an effective B-frame rate of 36 kHz, we are able to engineer vOMAG ...

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    6. Application of optical coherence tomography based microangiography for cerebral imaging

      Application of optical coherence tomography based microangiography for cerebral imaging

      Requirements of in vivo rodent brain imaging are hard to satisfy using traditional technologies such as magnetic resonance imaging and two-photon microscopy. Optical coherence tomography (OCT) is an emerging tool that can easily reach at high speeds and provide high resolution volumetric images with a relatively large field of view for rodent brain imaging. Here, we provide the overview of recent developments of functional OCT based imaging techniques for neuroscience applications on rodents. Moreover, a summary of OCT-based microangiography (OMAG) studies for stroke and traumatic brain injury cases on rodents are provided.

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    7. OCT-based label-free in vivo lymphangiography within human skin and areola

      OCT-based label-free in vivo lymphangiography within human skin and areola

      Due to the limitations of current imaging techniques, visualization of lymphatic capillaries within tissue in vivo has been challenging. Here, we present a label-free high resolution optical coherence tomography (OCT) based lymphangiography (OLAG) within human skin in vivo . OLAG enables rapid (~seconds) mapping of lymphatic networks, along with blood vessel networks, over 8 mm x 8 mm of human skin and 5 mm x 5 mm of human areola. Moreover, lymphatic system’s response to inflammation within human skin is monitored throughout an acne lesion development over 7 days. The demonstrated results promise OLAG as a revolutionary tool in the ...

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    8. Review of optical coherence tomography based angiography in neuroscience

      Review of optical coherence tomography based angiography in neuroscience

      The brain is a complex ecosystem, consisting of multiple layers and tissue compartments. To facilitate the understanding of its function and its response to neurological insults, a fast in vivo imaging tool with a micron-level resolution, which can provide a field of view at a few millimeters, is desirable. Optical coherence tomography (OCT) is a noninvasive method for imaging three-dimensional biological tissues with high resolution ( ∼ 10    μ m ∼10  μm ) and without a need for contrast agents. Recent development of OCT-based angiography has started to shed some new light on cerebral hemodynamics in neuroscience. We give an overview of the recent ...

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    9. Lymphatic response to depilation-induced inflammation in mouse ear assessed with label-free optical lymphangiography

      Lymphatic response to depilation-induced inflammation in mouse ear assessed with label-free optical lymphangiography

      Background and Objectives Optical microangiography (OMAG) is a noninvasive technique capable of imaging 3D microvasculature. OMAG-based optical lymphangiography has been developed for 3D visualization of lymphatic vessels without the need for exogenous contrast agents. In this study, we utilize the optical lymphangiography to investigate dynamic changes in lymphatic response within skin tissue to depilation-induced inflammation by using mouse ear as a simple tissue model. Materials and Methods A spectral-domain optical coherence tomography (OCT) system is used in this study to acquire volumetric images of mouse ear. The system operates under the ultrahigh-sensitive OMAG scanning protocol with five repetitions for each ...

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    10. In vivo tissue injury mapping using optical coherence tomography based methods

      In vivo tissue injury mapping using optical coherence tomography based methods

      An injury causes changes in the optical attenuation coefficient (OAC) of a light beam traveling inside a tissue. We report a method called tissue injury mapping (TIM), which utilizes a noninvasive in vivo optical coherence tomography approach to generate an OAC and microvascular map of the injured tissue. Using TIM, the infarct region development in a mouse cerebral cortex during a stroke is visualized. Moreover, we demonstrate the changes in human facial skin structure and microvasculature during an acne lesion development from initiation to scarring. The results indicate that TIM may be used to aid in the characterization and the ...

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    11. Vasodynamics of pial and penetrating arterioles in relation to arteriolo-arteriolar anastomosis after focal stroke

      Vasodynamics of pial and penetrating arterioles in relation to arteriolo-arteriolar anastomosis after focal stroke

      Changes in blood perfusion in highly interconnected pial arterioles provide important insights about the vascular response to ischemia within brain. The functional role of arteriolo-arteriolar anastomosis (AAA) in regulating blood perfusion through penetrating arterioles is yet to be discovered. We apply a label-free optical microangiography (OMAG) technique to evaluate the changes in vessel lumen diameter and red blood cell velocity among a large number of pial and penetrating arterioles within AAA abundant region overlaying the penumbra in the parietal cortex after a middle cerebral artery occlusion (MCAO). In comparison with two-photon microscopy, the OMAG technique makes it possible to image ...

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    12. In vivo blood flow imaging of inflammatory human skin induced by tape stripping using optical microangiography

      In vivo blood flow imaging of inflammatory human skin induced by tape stripping using optical microangiography

      Vasculature response is a hallmark for most inflammatory skin disorders. Tape stripping on human skin causes a minor inflammation which leads to changes in microvasculature. In this study, optical microangiography (OMAG), noninvasive volumetric microvasculature in vivo imaging method, has been used to track the vascular responses after tape stripping. Vessel density has been quantified and used to correlate with the degree of skin irritation. The proved capability of OMAG technique in visualizing the microvasculature network under inflamed skin condition can play an important role in clinical trials of treatment and diagnosis of inflammatory skin disorders.

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    13. High resolution imaging of acne lesion development and scarring in human facial skin using OCT-based microangiography

      High resolution imaging of acne lesion development and scarring in human facial skin using OCT-based microangiography

      Background and Objective Acne is a common skin disease that often leads to scarring. Collagen and other tissue damage from the inflammation of acne give rise to permanent skin texture and microvascular changes. In this study, we demonstrate the capabilities of optical coherence tomography-based microangiography in detecting high-resolution, three-dimensional structural, and microvascular features of in vivo human facial skin during acne lesion initiation and scar development. Materials and Methods A real time swept source optical coherence tomography system is used in this study to acquire volumetric images of human skin. The system operates on a central wavelength of 1,310 ...

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    14. MEMS scanning micromirror for optical coherence tomography

      MEMS scanning micromirror for optical coherence tomography

      This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique.

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    15. Motion artifact and background noise suppression on optical microangiography frames using a naïve Bayes mask

      Motion artifact and background noise suppression on optical microangiography frames using a naïve Bayes mask

      Optical coherence tomography (OCT) is a technique that allows for the three-dimensional (3D) imaging of small volumes of tissue (a few millimeters) with high resolution ( ∼ 10     μ m ). Optical microangiography (OMAG) is a method of processing OCT data, which allows for the extraction of the tissue vasculature with capillary resolution from the OCT images. Cross-sectional B-frame OMAG images present the location of the patent blood vessels; however, the signal-to-noise-ratio of these images can be affected by several factors such as the quality of the OCT system and the tissue motion artifact. This background noise can appear in the en face projection ...

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    1-15 of 15
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    1. (15 articles) University of Washington
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    Motion artifact and background noise suppression on optical microangiography frames using a naïve Bayes mask MEMS scanning micromirror for optical coherence tomography High resolution imaging of acne lesion development and scarring in human facial skin using OCT-based microangiography In vivo blood flow imaging of inflammatory human skin induced by tape stripping using optical microangiography Vasodynamics of pial and penetrating arterioles in relation to arteriolo-arteriolar anastomosis after focal stroke Lymphatic response to depilation-induced inflammation in mouse ear assessed with label-free optical lymphangiography Review of optical coherence tomography based angiography in neuroscience Automated segmentation and enhancement of optical coherence tomography-acquired images of rodent brain Tail artifact removal in OCT angiography images of rodent cortex Optical coherence tomography based microangiography provides an ability to longitudinally image arteriogenesis in vivo 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