Ultrahigh-speed optical coherence tomography imaging and visualization of the embryonic avian heart using a buffered Fourier Domain Mode Locked laser

Abstract

The embryonic avian heart is an important model for studying cardiac developmental biology. The mechanisms that govern the development of a four-chambered heart from a peristaltic heart tube are largely unknown due in part to a lack of adequate imaging technology. Due to the small size and rapid motion of the living embryonic avian heart, an imaging system with high spatial and temporal resolution is required to study these models. Here, an optical coherence tomography (OCT) system using a buffered Fourier Domain Mode Locked (FDML) laser is applied for ultrahigh-speed non-invasive imaging of embryonic quail hearts at 100,000 axial scans per second. The high scan rate enables the acquisition of high temporal resolution 2D datasets (195 frames per second or 5.12 ms between frames) and 3D datasets (10 volumes per second). Spatio-temporal details of cardiac motion not resolvable using previous OCT technology are analyzed. Visualization and measurement techniques are developed to non-invasively observe and quantify cardiac motion throughout the brief period of systole (less than 50 msec) and diastole. This marks the first time that the preseptated embryonic avian heart has been imaged in 4D without the aid of gating and the first time it has been viewed in cross section during looping with extremely high temporal resolution, enabling the observation of morphological dynamics of the beating heart during systole.

In vivo imaging of the cyclic changes in cross‐sectional shape of the ventricular segment of pulsating embryonic chick hearts at stages 14 to 17: A contribution to the understanding of the ontogenesis of cardiac pumping function

“…Movie S1, which is available online). Similar endocardial spikes have previously been noted on histological and optical sections from the outflow tract of the tubular embryonic chick heart (Fitzharris, 1981;Jenkins et al, 2007a;Rugonyi et al, 2008). We, therefore, wanted to disclose the exact time point of first appearance of these structures in the ventricular segment of the embryonic chick heart.…”

“…resolutions (8 frames/sec, 25 mm lateral resolution) compared with OCTsystems currently used by a few groups (Jenkins et al, 2007a;Gargesha et al, 2009). Moreover, as in our previous study, the acquisition of the present data was still made outside of an incubator under nonphysiological environmental conditions, which were expected to distort quantitative data (see the Experimental Procedures section).…”

Optical coherence tomography—current technology and applications in clinical and biomedical research

“…Various groups demonstrated anatomical and functional imaging of the developing cardiovascular system for different species, such as frog tadpoles [242,243], avian embryos (Fig. 12) [241,244], and mouse embryos [245].…”

“…Progress in OCT technology, for instance functional imaging [248,249], high-speed data acquisition [244] or advanced signal processing [250], has swiftly been adopted in developmental biology. These enabled further studies in early heart development and blood flow in various models establishing OCT as an important imaging tool for basic research.…”

In vivo imaging of murine endocrine islets of Langerhans with extended-focus optical coherence microscopy

“…Processing of this pattern extracts the sample structure along the axial direction in parallel without axial scanning and with a high resolution of 2-3 μm [16]. Together with its high sensitivity [17] that allows imaging several hundred micrometres into the tissue, Fourier domain OCT provides an exceptional speed advantage over other optical imaging methods, making it a confirmed tool for comprehensive volumetric imaging [18,19].…”