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The biophysical effects of blood flow are known to influence the structure and function of adult cardiovascular systems. Similar effects on the maturation of the cardiovascular system have been difficult to directly and non-invasively measure due to the small size of the embryo. Optical coherence tomography (OCT) has been shown to provide high spatial and temporal structural imaging of the early embryonic chicken heart. We have developed an extension of Doppler OCT, called spectral Doppler velocimetry (SDV), that will enable direct, non-invasive quantification of blood flow and shear rate from the early embryonic cardiovascular system. Using this technique, we calculated volumetric flow rate and shear rate from chicken embryo vitelline vessels. We present blood flow dynamics and spatial velocity profiles from three different vessels in the embryo as well as measurements from the outflow tract of the embryonic heart tube. This technology can potentially provide spatial mapping of blood flow and shear rate in embryonic cardiovascular structures, producing quantitative measurements that can be correlated with gene expression and normal and abnormal morphology.

We present an analysis of imaging murine embryos at various embryonic developmental stages (embryonic day 9.5, 11.5, and 13.5) by optical coherence tomography (OCT) and optical projection tomography (OPT). We demonstrate that while OCT was capable of rapid high-resolution live 3D imaging, its limited penetration depth prevented visualization of deeper structures, particularly in later stage embryos. In contrast, OPT was able to image the whole embryos, but could not be used in vivo because the embryos must be fixed and cleared. Moreover, the fixation process significantly altered the embryo morphology, which was quantified by the volume of the eye-globes before and after fixation. All of these factors should be weighed when determining which imaging modality one should use to achieve particular goals of a study.

The study of hemodynamic effects on embryonic cardiovascular development has been limited by technology. Here we present an extension to Doppler OCT which may provide insight in the relationship between blood flow and heart development.

The onset of congenital heart disease (CHD) is believed to occur at very early stages of development. Investigations in the initiation and development of CHD has been hampered by the inability to image early stage heart structure and function, in vivo. Imaging small animals using optical coherence tomography (OCT) has filled a niche between the limited penetration depth of confocal microscopy and insufficient resolution from ultrasound. Previous demonstrations of chick heart imaging using OCT have entailed excision of, or arresting the heart to prevent motion artifacts. In this summary, we introduce SDOCT Doppler velocimetry as an enhancement of Doppler OCT for in vivo measurement of localized temporal blood flow dynamics. With this technique, dynamic velocity waveforms were measured in the outflow tract of the heart tube. These flow dynamics correlate to a finite element model of pulsatile flow and may lead to a further understanding of morphological influences on early heart development.

We report on the development of quantitative, reproducible diagnostic observables for age-related macular degeneration (AMD) based on high speed spectral domain optical coherence tomography (SDOCT). 3D SDOCT volumetric data sets (512 x 1000 x 100 voxels) were collected (5.7 seconds acquisition time) in over 50 patients with age-related macular degeneration and geographic atrophy using a state-of-the-art SDOCT scanner. Commercial and custom software utilities were used for manual and semi-automated segmentation of photoreceptor layer thickness, total drusen volume, and geographic atrophy cross-sectional area. In a preliminary test of reproducibility in segmentation of total drusen volume and geographic atrophy surface area, inter-observer error was less than 5%. Extracted volume and surface area of AMD-related drusen and geographic atrophy, respectively, may serve as useful observables for tracking disease state that were not accessible without the rapid 3D volumetric imaging capability unique to retinal SDOCT.

Objective: The purpose of this investigation was to develop techniques to non-invasively measure blood flow velocities in the tubular embryonic chick heart with optical coherence tomography (OCT) t...

1300nm Doppler spectral-domain OCT microscopy provides a high-speed, high-resolution solution for imaging of developmental processes in small animals. We present 3D volume renderings, Doppler images and M-mode Doppler recordings elucidating cardiac development in chick embryos.

Progress toward understanding embryonic heart development has been hampered by the inability to image embryonic heart structure and simultaneously measure blood flow dynamics in vivo. We have developed a spectral domain optical coherence tomography system for in vivo volumetric imaging of the chicken embryo heart. We have also developed a technique called spectral Doppler velocimetry (SDV) for quantitative measurement of blood flow dynamics. We present in vivo volume images of the embryonic heart from initial tube formation to development of endocardial cushions of the same embryo over several stages of development. SDV measurements reveal the influence of heart tube structure on blood flow dynamics.

The present subject matter relates to in vivo volumetric bidirectional blood flow imaging using single-pass flow imaging spectral domain optical coherence tomography. This technique uses a modified Hilbert transform algorithm to separate moving and non-moving scatterers within a depth. The resulting reconstructed image maps the components of moving scatterers flowing into and out of the imaging axis onto opposite image halfplanes, enabling volumetric bidirectional flow mapping without manual segmentation.