1. Articles from michael w. jenkins

    1-24 of 29 1 2 »
    1. Imaging of Atrioventricular Nodal Conduction Tissue in Porcine Hearts Using Optical Coherence Tomography

      Imaging of Atrioventricular Nodal Conduction Tissue in Porcine Hearts Using Optical Coherence Tomography

      Optical coherence tomography (OCT) employs near-infrared light to image the microstructure of different tissues. Clinically, it has been used to image the walls of coronary arteries. In research settings, one of the applications for OCT is visualizing endocardial and subendocardial structures. The present experiment sought to determine whether OCT can identify native conduction tissues in adult porcine hearts. During the study, the right atrial endocardial surfaces of excised adult porcine hearts were exposed. The triangle of Koch was imaged with the OCT system and the conduction tissue was identified. The area was then prepared for histologic examination with Masson’s ...

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    2. Intracardiac radiofrequency ablation in living swine guided by polarization-sensitive optical coherence tomography

      Intracardiac radiofrequency ablation in living swine guided by polarization-sensitive optical coherence tomography

      Significance: Pulmonary vein isolation with catheter-based radiofrequency ablation (RFA) is carried out frequently to treat atrial fibrillation. However, RFA lesion creation is only guided by indirect information (e.g., temperature, impedance, and contact force), which may result in poor lesion quality (e.g., nontransmural) and can lead to reoccurrence or complications. Aim: The feasibility of guiding intracardiac RFA with an integrated polarization-sensitive optical coherence tomography (PSOCT)-RFA catheter in the right atria (RA) of living swine is demonstrated. Approach : In total, 12 sparse lesions were created in the RA of three living swine using an integrated PSOCT-RFA catheter with standard ...

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    3. SLIME: robust, high-speed 3D microvascular mapping

      SLIME: robust, high-speed 3D microvascular mapping

      Three dimensional (3D) microvascular imaging of cubic millimeter to centimeter size volumes often requires much time and expensive instruments. By combining optical clearing with a novel scatter-based optical coherence tomography (OCT) contrast agent, we have greatly extended OCT imaging depth in excised tissues while maintaining a simple and low cost approach that does not require in-depth OCT knowledge. The new method enables fast 3D microvascular mapping in large tissue volumes, providing a promising tool for investigating organ level microvascular abnormalities in large cohorts.

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    4. Noninvasive Assessment of Corneal Crosslinking With Phase-Decorrelation Optical Coherence Tomography

      Noninvasive Assessment of Corneal Crosslinking With Phase-Decorrelation Optical Coherence Tomography

      Purpose : There is strong evidence that abnormalities in corneal biomechanical play a causal role in corneal ectasias, such as keratoconus. Additionally, corneal crosslinking (CXL) treatment, which halts progression of keratoconus, directly appeals to corneal biomechanics. However, existing methods of corneal biomechanical assessment have various drawbacks: dependence on IOP, long acquisition times, or limited resolution. Here, we present a method that may avoid these limitations by using optical coherence tomography (OCT) to detect the endogenous random motion within the cornea, which can be associated with stromal crosslinking. Methods : Phase-decorrelation OCT (PhD-OCT), based in the theory of dynamic light scattering, is a ...

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    5. Complex regression Doppler optical coherence tomography

      Complex regression Doppler optical coherence tomography

      We introduce a new method to measure Doppler shifts more accurately and extend the dynamic range of Doppler optical coherence tomography (OCT). The two-point estimate of the conventional Doppler method is replaced with a regression that is applied to high-density B-scans in polar coordinates. We built a high-speed OCT system using a 1.68-MHz Fourier domain mode locked laser to acquire high-density B-scans (16,000 A-lines) at high enough frame rates (∼100  fps) to accurately capture the dynamics of the beating embryonic heart. Flow phantom experiments confirm that the complex regression lowers the minimum detectable velocity from 12.25  mm ...

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    6. Using optical coherence tomography to detect disturbances in coronary microvascular in a model of fetal alcohol syndrome

      Using optical coherence tomography to detect disturbances in coronary microvascular in a model of fetal alcohol syndrome

      Congenital coronary anomalies can result in severe consequences such as arrhythmias and sudden death. However, the etiology of abnormal embryonic coronary microvasculature development is understudied. Using a novel contrast-agent-based optical coherence tomography (OCT) technique, scatter labeled imaging of microvasculature in excised tissue (SLIME), we compared diseased and normal embryonic quail coronary microvasculature in 3D. Congenital heart defects associated with fetal alcohol syndrome (FAS) were induced in a quail model by injecting 40 uL of 50% ethanol solution into eggs during gastrulation. These and saline-injected quail eggs were incubated until stage 36. SLIME contrast agent was perfused through the aortas of ...

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    7. Postdoctoral Fellow Positions at Case Western Reserve University

      Postdoctoral Fellow Positions at Case Western Reserve University

      Location: Case Western Reserve University, Cleveland, OH, 44106-7080 Application Deadline: Open until filled, available immediately Job description: Post-doctoral research training positions available immediately to join a team of biomedical engineers, neurobiologists, and electrophysiologists to assess the mechanisms by which infrared light (infrared neuromodulation - IRN) can modulate axons and neurons in ganglia as a therapeutic alternative to systemic drug delivery, as well as creating novel tools for visualizing and manipulating neurons and axons using infrared light. Successful applicants will be expected to work in an interdisciplinary team, including coordination with research and clinical collaborators and providing leadership to junior researchers. Outstanding ...

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    8. Complex decorrelation averaging in optical coherence tomography: a way to reduce the effect of multiple scattering and improve image contrast in a dynamic scattering medium

      Complex decorrelation averaging in optical coherence tomography: a way to reduce the effect of multiple scattering and improve image contrast in a dynamic scattering medium

      We demonstrate that complex decorrelation averaging can reduce the effect of multiple scattering and improve optical coherence tomography (OCT) imaging contrast. Complex decorrelation averaging calculates the product of an A-scan and the complex conjugate of a subsequent A-scan. The resultant signal is the product of the amplitudes and the phase difference. All these resulting complex signals at a particular location are then averaged. We take advantage of the fact that complex averaging, in contrast to conventional magnitude averaging, is sensitive to phase decorrelation. Sample motion that increases signal phase variance results in lower signal magnitude after complex averaging. Such motion ...

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    9. CUG-BP, Elav-like family member 1 (CELF1) is required for normal myofibrillogenesis, morphogenesis, and contractile function in the embryonic heart

      CUG-BP, Elav-like family member 1 (CELF1) is required for normal myofibrillogenesis, morphogenesis, and contractile function in the embryonic heart

      Background : CUG-BP, Elav-like family member 1 (CELF1) is a multifunctional RNA binding protein found in a variety of adult and embryonic tissues. In the heart, CELF1 is found exclusively in the myocardium. However, the roles of CELF1 during cardiac development have not been completely elucidated. Results : Myofibrillar organization is disrupted and proliferation is reduced following knockdown of CELF1 in cultured chicken primary embryonic cardiomyocytes. In vivo knockdown of Celf1 in developing Xenopus laevis embryos resulted in myofibrillar disorganization and a trend towards reduced proliferation in heart muscle, indicating conserved roles for CELF1 orthologs in embryonic cardiomyocytes. Loss of Celf1 also ...

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    10. Measurement Of Biomechanical Properties In An OCT Image

      Measurement Of Biomechanical Properties In An OCT Image

      Systems and method are provided for evaluating a biomechanical property of tissue. A shear wave generator is configured to induce a shear wave in the tissue. An optical coherence tomography (OCT) imager is configured to capture a B-scan frame of the tissue. An image processing component is configured to determine a frequency of the shear wave in the tissue from the B-scan frame of the tissue at each of a plurality of locations within the B-scan.

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    11. 3-D Stent Detection in Intravascular OCT Using a Bayesian Network and Graph Search

      3-D Stent Detection in Intravascular OCT Using a Bayesian Network and Graph Search

      Worldwide, many hundreds of thousands of stents are implanted each year to revascularize occlusions in coronary arteries. Intravascular optical coherence tomography (OCT) is an important emerging imaging technique, which has the resolution and contrast necessary to quantitatively analyze stent deployment and tissue coverage following stent implantation. Automation is needed, as current, it takes up to 16 hours to manually analyze hundreds of images and thousands of stent struts from a single pullback. For automated strut detection, we used image formation physics and machine learning via a Bayesian network, and 3-D knowledge of stent structure via graph search. Graph search was ...

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    12. Feature Of The Week 02/22/15: Case Western Reserve University Demostrates Using OCT to Rapidly Phenotype and Quantify Congenital Heart Defects Associated with Prenatal Alcohol Exposure

      Feature Of The Week 02/22/15:  Case Western Reserve University Demostrates Using OCT to Rapidly Phenotype and Quantify Congenital Heart Defects Associated with Prenatal Alcohol Exposure

      The most commonly used method to analyze congenital heart defects involves serial sectioning and histology. However, this is often a time-consuming process where the quantification of cardiac defects can be difficult due to problems with accurate section registration. Here we demonstrate the advantages of using optical coherence tomography, a comparatively new and rising technology, to phenotype avian embryo hearts in a model of Fetal Alcohol Syndrome where a binge-like quantity of alcohol/ethanol was introduced at gastrulation. The rapid, consistent imaging protocols allowed for the immediate identification of cardiac anomalies, including ventricular septal defects and misaligned/missing vessels. Interventricular septum ...

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    13. Using optical coherence tomography to rapidly phenotype and quantify congenital heart defects associated with prenatal alcohol exposure

      Using optical coherence tomography to rapidly phenotype and quantify congenital heart defects associated with prenatal alcohol exposure

      Background : The most commonly used method to analyze congenital heart defects involves serial sectioning and histology. However, this is often a time-consuming process where the quantification of cardiac defects can be difficult due to problems with accurate section registration. Here we demonstrate the advantages of using optical coherence tomography, a comparatively new and rising technology, to phenotype avian embryo hearts in a model of Fetal Alcohol Syndrome where a binge-like quantity of alcohol/ethanol was introduced at gastrulation. Results : The rapid, consistent imaging protocols allowed for the immediate identification of cardiac anomalies, including ventricular septal defects and misaligned/missing vessels ...

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    14. Capturing structure and function in an embryonic heart with biophotonic tools

      Capturing structure and function in an embryonic heart with biophotonic tools

      Disturbed cardiac function at an early stage of development has been shown to correlate with cellular/molecular, structural as well as functional cardiac anomalies at later stages culminating in the congenital heart defects (CHDs) that present at birth. While our knowledge of cellular and molecular steps in cardiac development is growing rapidly, our understanding of the role of cardiovascular function in the embryo is still in an early phase. One reason for the scanty information in this area is that the tools to study early cardiac function are limited. Recently developed and adapted biophotonic tools may overcome some of the ...

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    15. Fiber-optic catheter-based polarization-sensitive OCT for radio-frequency ablation monitoring

      Fiber-optic catheter-based polarization-sensitive OCT for radio-frequency ablation monitoring

      An all-fiber optic catheter-based polarization-sensitive optical coherence tomography system is demonstrated. A novel multiplexing method was used to illuminate the sample, splitting the light from a 58.5 kHz Fourier-domain mode-locked laser such that two different polarization states, alternated in time, are generated by two semiconductor optical amplifiers. A 2.3 mm forward-view cone-scanning catheter probe was designed, fabricated, and used to acquire sample scattering intensity and phase retardation images. The system was first verified with a quarter-wave plate and then by obtaining intensity and phase retardation images of high-birefringence plastic, human skin in vivo , and untreated and thermally ablated ...

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    16. Three-dimensional correction of conduction velocity in the embryonic heart using integrated optical mapping and optical coherence tomography

      Three-dimensional correction of conduction velocity in the embryonic heart using integrated optical mapping and optical coherence tomography

      Optical mapping (OM) of cardiac electrical activity conventionally collects information from a three-dimensional (3-D) surface as a two-dimensional (2-D) projection map. When applied to measurements of the embryonic heart, this method ignores the substantial and complex curvature of the heart surface, resulting in significant errors when calculating conduction velocity, an important electrophysiological parameter. Optical coherence tomography (OCT) is capable of imaging the 3-D structure of the embryonic heart and accurately characterizing the surface topology. We demonstrate an integrated OCT/OM imaging system capable of simultaneous conduction mapping and 3-D structural imaging. From these multimodal data, we obtained 3-D activation maps ...

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    17. Ethanol exposure alters early cardiac function in the looping heart: a mechanism for congenital heart defects?

      Ethanol exposure alters early cardiac function in the looping heart: a mechanism for congenital heart defects?

      Alcohol-induced congenital heart defects (CHDs) are frequently among the most life-threatening and require surgical correction in newborns. The etiology of these defects, collectively known as Fetal Alcohol Syndrome (FAS), has been the focus of much study, particularly involving cellular and molecular mechanisms. Few studies have addressed the influential role of altered cardiac function in early embryogenesis, due to a lack of tools with the capability to assay tiny beating hearts. To overcome this gap in our understanding, we used optical coherence tomography (OCT), a non-destructive imaging modality capable of micrometer-scale resolution imaging, to rapidly and accurately map cardiovascular structure and ...

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    18. 4D shear stress maps of the developing heart using Doppler optical coherence tomography

      4D shear stress maps of the developing heart using Doppler optical coherence tomography

      Accurate imaging and measurement of hemodynamic forces is vital for investigating how physical forces acting on the embryonic heart are transduced and influence developmental pathways. Of particular importance is blood flow-induced shear stress, which influences gene expression by endothelial cells and potentially leads to congenital heart defects through abnormal heart looping, septation, and valvulogenesis. However no imaging tool has been available to measure shear stress on the endocardium volumetrically and dynamically. Using 4D structural and Doppler OCT imaging, we are able to accurately measure the blood flow in the heart tube in vivo and to map endocardial shear stress throughout ...

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    19. Longitudinal Imaging of Heart Development With Optical Coherence Tomography

      Longitudinal Imaging of Heart Development With Optical Coherence Tomography

      Optical coherence tomography (OCT) has great potential for deciphering the role of mechanics in normal and abnormal heart development. OCT images tissue microstructure and blood flow deep into the tissue (1-2 mm) at high spatiotemporal resolutions allowing unprecedented images of the developing heart. Here, we review the advancement of OCT technology to image heart development and report some of our recent findings utilizing OCT imaging under environmental control for longitudinal imaging. Precise control of the environment is absolutely required in longitudinal studies that follow the growth of the embryo or studies comparing normal versus perturbed heart development to obtain meaningful ...

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    20. Optical coherence tomography captures rapid hemodynamic responses to acute hypoxia of the embryonic cardiovascular system of Early Embryos

      Optical coherence tomography captures rapid hemodynamic responses to acute hypoxia of the embryonic cardiovascular system of Early Embryos

      Background.The trajectory to heart defects may start in tubular and looping heart stages when detailed analysis of form and function is difficult by currently available methods. We used a novel method, Doppler optical coherence tomography (OCT), to follow changes in cardiovascular function in quail embryos during acute hypoxic stress. Chronic fetal hypoxia is a known risk factor for congenital heart diseases (CHDs). Decreased fetal heart rates during maternal obstructive sleep apnea suggest that studying fetal heart responses under acute hypoxia is warranted.Results.We captured responses to hypoxia at the critical looping heart stages. Doppler OCT revealed detailed vitelline ...

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    21. Motion artifacts associated with in vivo endoscopic OCT images of the esophagus

      Motion artifacts associated with in vivo endoscopic OCT images of the esophagus
      3-D optical coherence tomography (OCT) has been extensively investigated as a potential screening and/or surveillance tool for Barrett’s esophagus (BE). Understanding and correcting motion artifact may improve image interpretation. In this work, the motion trace was analyzed to show the physiological origin (respiration and heart beat) of the artifacts. Results showed that increasing balloon pressure did not sufficiently suppress the physiological motion artifact. An automated registration algorithm was designed to correct such artifacts. The performance of the algorithm was evaluated in images of normal porcine esophagus and demonstrated in images of BE in human patients.
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    22. Optical Coherence Tomography Imaging of Early Quail Embryos

      Optical Coherence Tomography Imaging of Early Quail Embryos
      Congenital heart defects (CHDs) affect thousands of newborns each year in the United States. Recent research using animal model systems indicates that the abnormal function of the early tubular heart precedes structural defects such as septal defects. Optical coherence tomography (OCT) is an imaging modality that can provide high spatial and temporal resolution to study both the structure and the function of the tubular heart. With technical advances in OCT imaging speed, especially with frequency domain OCT and image-based retrospective gating, it is now possible to image a beating avian embryonic heart in three dimensions under physiological conditions and follow ...
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    23. High-Speed Optical Coherence Tomography Imaging of the Beating Avian Embryonic Heart

      High-Speed Optical Coherence Tomography Imaging of the Beating Avian Embryonic Heart
      Congenital heart defects (CHDs) affect thousands of newborns each year in the United States. Recent research using animal model systems indicates that the abnormal function of the early tubular heart precedes structural defects such as septal defects. Optical coherence tomography (OCT) is an imaging modality that can provide high spatial and temporal resolution to study both the structure and the function of the tubular heart. With technical advances in OCT imaging speed, especially with frequency domain OCT and image-based retrospective gating, it is now possible to image a beating avian embryonic heart in three dimensions under physiological conditions and follow ...
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    24. Blood Flow Dynamics of One Cardiac Cycle and Relationship to Mechanotransduction and Trabeculation during Heart Looping

      Blood Flow Dynamics of One Cardiac Cycle and Relationship to Mechanotransduction and Trabeculation during Heart Looping
      Analyses of form-function relationships during heart looping are directly related to technological advances. Recent advances in 4-D optical coherence tomography (OCT) permit observations of cardiac dynamics at high speed acquisition rates and high resolution. Real-time observation of the avian stage 13 looping heart reveals that interactions between the endocardial and myocardial compartments are more complex than previously depicted. Here we applied 4-D OCT to elucidate the relationships of the endocardium, myocardium, and cardiac jelly compartments in a single cardiac cycle during looping. Six cardiac levels along the longitudinal heart tube were each analyzed at 15 time points from diastole to ...
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    1-24 of 29 1 2 »
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    1. (29 articles) Case Western Reserve University
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    Imaging the Embryonic Heart with Optical Coherence Tomography (Thesis) Endoscopically guided spectral-domain OCT with double-balloon catheters Measuring hemodynamics in the developing heart tube with four-dimensional gated Doppler optical coherence tomography Blood Flow Dynamics of One Cardiac Cycle and Relationship to Mechanotransduction and Trabeculation during Heart Looping High-Speed Optical Coherence Tomography Imaging of the Beating Avian Embryonic Heart Optical coherence tomography captures rapid hemodynamic responses to acute hypoxia of the embryonic cardiovascular system of Early Embryos Longitudinal Imaging of Heart Development With Optical Coherence Tomography 4D shear stress maps of the developing heart using Doppler optical coherence tomography Postdoctoral Fellow Positions at Case Western Reserve University Optical Coherence Tomography: Critical Tool to Manage Expectations after Cataract Extraction Improving the characterization of ex vivo human brain optical properties using high numerical aperture optical coherence tomography by spatially constraining the confocal parameters Choroidal, macular and ganglion cell layer thickness assessment in Caucasian children measured with spectral domain optical coherence tomography