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

Optical coherence tomography (OCT) is a non-contact, non-invasive and highresolution imaging technique, suited to study early cardiovascular development. Alterations in hemodynamic conditions during early development are known to lead to cardiac defects, presumably as a result of changes in cardiac biomechanics produced by the alterations. In this paper, we demonstrate the use of a spectral domain OCT in visualizing and quantifying changes in cardiac wall motion and blood-flow velocities under normal and altered hemodynamic conditions in chicken embryos at an early stage of development (Hamburger-Hamilton stage HH18, similar to 3 days of incubation), focusing on the heart outflow tract ( OFT). The OCT system employed acquired simultaneously microstructural and blood-flow images at a rate of 92 frames s(-1) with a spatial resolution of similar to 10 mu m. OCT imaging allowed in vivo visualization of the OFT microstructures, e. g. the lumen, cardiac cushions and myocardium. We found that alterations in hemodynamic conditions, through OFT banding and vitellinevein ligation, changed blood-flow velocities through the OFT, as expected. Further, OCT allowed quantification of changes in the dynamics of OFT wall motion. Our results therefore establish the utility of spectral domain OCT to study the influence of hemodynamic conditions on heart development in intact, in vivo chicken embryo models.