The most common and lethal birth defects affect the cardiovascular (CV) system. The mouse is a superior model for identifying and understanding mammalian CV birth defects, but there is a great need for tools that can detect early and subtle deficiencies in cardiac function in mouse embryos. We combined swept source optical coherence tomography (SS-OCT) with live mouse embryo culture protocols to generate structural two-dimensional and three-dimensional imaging and hemodynamic measurements in a live 8.5 day embryo just a few hours after the beginning of a heartbeat. Our data show that individual circulating blood cells can be visualized with structural SS-OCT, and using Doppler SS-OCT the velocity of single moving blood cells were measured during different phases of the heartbeat cycle. These results demonstrate that Doppler SS-OCT is an extremely useful tool for structural and hemodynamic analysis at the earliest stages of mammalian blood circulation.There is a great need for tools to characterize dynamic aspects of mammalian embryonic cardiovascular (CV) development in mutant embryos to reveal the genetic basis of functional deficiencies. Recent advances in optical coherence tomography (OCT) have rapidly led to the application of this exciting imaging modality for live imaging of embryonic cardio dynamics and blood flow in Drosophila [1], Xenopus laevis [2,3], quail [4], and chick [5]. Despite the obvious need to address questions regarding mammalian embryonic development, there have been only a few OCT studies. Jenkins et al. [6] performed three-dimesional (3D) OCT imaging of excised and externally paced beating embryonic mouse hearts at 13.5 dpc. Luo et al. [7] reported imaging of beating 10.5 dpc hearts in embryos that were maintained outside the uterus, but the heartbeat was significantly slower than normal. Our group has previously developed protocols for maintenance and the growth of 5.5-10.5 dpc mouse embryos in static culture [8] and has successfully applied these protocols for characterization of blood flow phenotypes using confocal microscopic imaging [9]. Recently, we combined Doppler swept source optical coherence tomography (SS-OCT) analysis with mouse embryo culture protocols for live 3D embryonic imaging and reconstructed spatially and temporally resolved Doppler shift velocity profiles from deep 9.5 dpc embryonic vessels in which flow is well established [10].In this Letter, we applied Doppler SS-OCT to perform hemodynamic measurements at an earlier embryonic stage, 8.5 dpc, just a few hours after the beginning of a heartbeat when blood circulation first begins. At this stage, the majority of blood cells are still found in the blood islands with limited numbers of circulating erythroblasts [9]. Thus, we focused this Letter on OCT signal detection from single circulating blood cells. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptThe experimental SS-OCT setup was similar to the system described in [10]. Briefly, the system utilizes a broadband swept source lase...

Several investigations suggest that the early stages of atherosclerosis are modulated by the selective permeability of the vascular tissue to pro-inflammatory molecules of different molecular weights. Up to date, a few experiments have been performed to study the permeability of arterial tissue to different molecules. This is primarily due to an absence of an experimental technique capable of depth-resolved, accurate and sensitive assessment of arterial permeability. In this paper, we report our pilot results on nondestructive quantification of glucose diffusion in animal arteries in vitro by using optical coherence tomography (OCT) technique. Permeability of glucose in animal's aorta was estimated to be 1.43 ± 0.24 × 10 −5 cm/sec from five independent experiments. Obtained results suggest capability of OCT technique for highly sensitive, accurate, and nondestructive monitoring and quantification of agents' diffusion in vascular tissues.OCT signal slope, arb. units 1.00

A new approach to in vivo biosensor design is introduced, based on the use of an implantable micron-sized retroreflector-based platform and non-invasive imaging of its surface reflectivity by Optical Coherence Tomography (OCT). The possibility of using OCT for the depth-resolved imaging and detection of micro-retroreflectors in highly turbid media, including tissue, is demonstrated. The maximum imaging depth for the detection of the micro-retroreflector-based platform within the surrounding media was found to be 0.91 mm for porcine tissue and 1.65 mm for whole milk. With further development, it may be possible to utilize OCT and micro-retroreflectors as a tool for continuous monitoring of analytes in the subcutaneous tissue.

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