1. Articles from aiping liu

    1-10 of 10
    1. Effect of Outflow Tract Banding on Embryonic Cardiac Hemodynamics

      Effect of Outflow Tract Banding on Embryonic Cardiac Hemodynamics

      We analyzed heart wall motion and blood flow dynamics in chicken embryos using in vivo optical coherence tomography (OCT) imaging and computational fluid dynamics (CFD) embryo-specific modeling. We focused on the heart outflow tract (OFT) region of day 3 embryos, and compared normal (control) conditions to conditions after performing an OFT banding intervention, which alters hemodynamics in the embryonic heart and vasculature. We found that hemodynamics and cardiac wall motion in the OFT are affected by banding in ways that might not be intuitive a priori . In addition to the expected increase in ventricular blood pressure, and increase blood flow ...

      Read Full Article
    2. Extracting cardiac shapes and motion of the chick embryo heart outflow tract from four-dimensional optical coherence tomography images

      Extracting cardiac shapes and motion of the chick embryo heart outflow tract from four-dimensional optical coherence tomography images

      Recent advances in optical coherence tomography (OCT), and the development of image reconstruction algorithms, enabled four-dimensional (4-D) (three-dimensional imaging over time) imaging of the embryonic heart. To further analyze and quantify the dynamics of cardiac beating, segmentation procedures that can extract the shape of the heart and its motion are needed. Most previous studies analyzed cardiac image sequences using manually extracted shapes and measurements. However, this is time consuming and subject to inter-operator variability. Automated or semi-automated analyses of 4-D cardiac OCT images, although very desirable, are also extremely challenging. This work proposes a robust algorithm to semi automatically detect ...

      Read Full Article
    3. Biomechanics of the Chick Embryonic Heart Outflow Tract at HH18 Using 4D Optical Coherence Tomography Imaging and Computational Modeling

      Biomechanics of the Chick Embryonic Heart Outflow Tract at HH18 Using 4D Optical Coherence Tomography Imaging and Computational Modeling

      During developmental stages, biomechanical stimuli on cardiac cells modulate genetic programs, and deviations from normal stimuli can lead to cardiac defects. Therefore, it is important to characterize normal cardiac biomechanical stimuli during early developmental stages. Using the chicken embryo model of cardiac development, we focused on characterizing biomechanical stimuli on the Hamburger–Hamilton (HH) 18 chick cardiac outflow tract (OFT), the distal portion of the heart from which a large portion of defects observed in humans originate. To characterize biomechanical stimuli in the OFT, we used a combination of in vivo optical coherence tomography (OCT) imaging, physiological measurements and computational ...

      Read Full Article
    4. Assessment of strain and strain rate in embryonic chick heart in vivo using tissue Doppler optical coherence tomography

      Assessment of strain and strain rate in embryonic chick heart in vivo using tissue Doppler optical coherence tomography

      We present a method to assess the in vivo radial strain and strain rate of the myocardial wall, which is of great importance to understand the biomechanics of cardiac development, using tissue Doppler optical coherence tomography (tissue-DOCT). Combining the structure and velocity information acquired from tissue-DOCT, the velocity distribution in the myocardial wall is plotted, from which the radial strain and strain rate are evaluated. The results demonstrate that tissue-DOCT can be used as a useful tool to describe tissue deformation, especially, the biomechanical characteristics of the embryonic heart.

      Read Full Article
    5. Measurement of strain and strain rate in embryonic chick heart in vivo using spectral domain optical coherence tomography

      Measurement of strain and strain rate in embryonic chick heart in vivo using spectral domain optical coherence tomography

      The ability to measure in vivo strain and strain rate in embryonic chick heart is one of the key requirements for understanding the mechanisms of cardiac development. Due to its high temporal and spatial resolution as well as its fast imaging capability, optical coherence tomography (OCT) has the potential to reveal the complex myocardial activity in the living chick heart. We describe a method to evaluate the in vivo strain and strain rate of the myocardium through analyzing the periodic variation of the myocardial wall thickness calculated from real time serial OCT images. The results demonstrate that OCT can be ...

      Read Full Article
    6. Imaging and modeling of blood flow in the developing heart

      Imaging and modeling of blood flow in the developing heart

      Blood flow during early embryonic development modulates the growth and remodeling (volume and shape) of the heart. Several studies in animals have shown that altered hemodynamic conditions during embryonic development resulted in cardiac defects resembling those in the 1% of human newborns with congenital heart disease. To better understand the relationship between blood flow and cardiac development, as well as the mechanisms by which blood flow affects heart growth, we must quantify intracardiac blood-flow velocities during early embryonic development. There are, however, two main challenges in measuring blood-flow dynamics in the developing heart. The heart is tiny (<1mm) and it ...

      Read Full Article
    7. Measurement of absolute blood flow velocity in outflow tract of HH18 chicken embryo based on 4D reconstruction using spectral domain optical coherence tomography

      Measurement of absolute blood flow velocity in outflow tract of HH18 chicken embryo based on 4D reconstruction using spectral domain optical coherence tomography

      The measurement of blood-plasma absolute velocity distributions with high spatial and temporal resolution in vivo is important for the investigation of embryonic heart at its early stage of development. We introduce a novel method to measure absolute blood flow velocity based on high speed spectral domain optical coherence tomography (OCT) and apply it to measure velocities across the heart outflow tract (OFT) of a chicken embryo (stage HH18). First, we use the OCT system to acquire 4D 
[(x,y,z) + t] images of the OFT in vivo. Second, we reconstruct the 4D microstructural images and obtain the orientation of the ...

      Read Full Article
    8. Efficient postacquisition synchronization of 4-D nongated cardiac images obtained from optical coherence tomography: application to 4-D reconstruction of the chick embryonic heart

      Four-dimensional (4-D) imaging of the embryonic heart allows study of cardiac morphology and function in vivo during development. However, 4-D imaging of the embryonic heart using current techniques, including optical coherence tomography (OCT), is limited by the rate of image acquisition. Here, we present a nongated 4-D imaging strategy combined with an efficient postacquisition synchronization procedure that circumvents limitations on acquisition rate. The 4-D imaging strategy acquires a time series of images in B mode at several different locations along the heart, rendering out-of-phase image sequences. Then, our synchronization procedure uses similarity of local structures to find the phase shift ...
      Read Full Article
    9. Dynamic variation of hemodynamic shear stress on the walls of developing chick hearts: computational models of the heart outflow tract

      Abstract  Heart morphogenesis and growth are influenced by hemodynamic forces (wall shear stress and blood pressure) acting on the walls of the heart. Mechanisms by which hemodynamic forces affect heart development are not well understood, in part because of difficulties involved in measuring these forces in vivo. In this paper, we show how wall shear stress in the heart outflow tract (OFT) of chick embryos at an early developmental stage (HH18) are affected by changes in the geometry and motion of the OFT wall. In particular, we were interested in the effects of cardiac cushions, which are protrusions of the ...
      Read Full Article
    10. Changes in wall motion and blood flow in the outflow tract of chick embryonic hearts observed with optical coherence tomography after outflow tract banding and vitelline-vein ligation

      Author(s): Sandra Rugonyi, Carley Shaut, Aiping Liu, Kent Thornburg and Ruikang K Wang. Affiliation(s): Division of Biomedical Engineering, Oregon Health & Science University, 3303 SW Bond Ave., CH13B, Portland, OR 97239, USA; Heart Research Center, Oregon Health & Science University, Portland, OR, USA
      Read Full Article
    1-10 of 10
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (10 articles) Oregon Health & Science University
    2. (8 articles) Ruikang K. Wang
    3. (6 articles) Xin Yin
    4. (5 articles) University of Washington
    5. (4 articles) Massachusetts General Hospital
    6. (3 articles) University of Wisconsin
    7. (3 articles) Peng Li
    8. (1 articles) Texas A&M University
    9. (1 articles) Stanford University
    10. (1 articles) Harvard University
    11. (1 articles) Kawasaki Medical School
    12. (1 articles) University of Washington
    13. (1 articles) Brigham and Women’s Hospital
    14. (1 articles) L V Prasad Eye Institute
    15. (1 articles) Ruikang K. Wang
    16. (1 articles) Sirisha Senthil
    17. (1 articles) Canon Medical Systems
  3. Popular Articles

  4. Picture Gallery

    Measurement of absolute blood flow velocity in outflow tract of HH18 chicken embryo based on 4D reconstruction using spectral domain optical coherence tomography Imaging and modeling of blood flow in the developing heart Measurement of strain and strain rate in embryonic chick heart in vivo using spectral domain optical coherence tomography Assessment of strain and strain rate in embryonic chick heart in vivo using tissue Doppler optical coherence tomography Biomechanics of the Chick Embryonic Heart Outflow Tract at HH18 Using 4D Optical Coherence Tomography Imaging and Computational Modeling Extracting cardiac shapes and motion of the chick embryo heart outflow tract from four-dimensional optical coherence tomography images Effect of Outflow Tract Banding on Embryonic Cardiac Hemodynamics Image contrast correction method in full-field optical coherence tomography Evaluation of posterior vitreous detachment using ultrasonography and optical coherence tomography Optical coherence tomography angiography characteristics of acute retinal arterial occlusion Computed Tomography–Mediated Registration of Trapeziometacarpal Articular Cartilage Using Intraarticular Optical Coherence Tomography and Cryomicrotome Imaging: A Cadaver Study Successful Treatment of Genital Warts with Ingenol Mebutate Monitored with Optical Coherence Tomography and Reflectance Confocal Microscopy