The objective of this study was to evaluate two Doppler frequency-detection methods to measure blood flow velocity in the developing chick embryo. We compared the commonly used directional zero-crossing counter and a customized digital bidirectional spectrum analyzer. At development stages 16 up to 28 (2.5 to 6 days incubation), a reversed flow component in the dorsal aorta was demonstrated using the bidirectional spectrum analyzer. Dorsal aortic velocities obtained with the directional zero-crossing counter were significantly lower than with the bidirectional spectrum analyzer in stages 16, 20 and 28. In addition to the differences in the absolute velocity values, there was also a remarkable discrepancy in the velocity waveform shape using the two Doppler frequency processors. The calculated heart rate using the two Doppler frequency processors was identical. It is concluded that a Doppler velocity detector based on spectral analysis is superior to the hitherto used zero-crossing counter in the chick embryo. With the customized digital bidirectional spectrum analyzer, we can accurately measure the hemodynamics of the developing chick embryo.

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Ultrasound in Medicine & Biology
Department of Gynaecology & Obstetrics

Ursem, N.T.C, Struijk, P.C, Poelmann, R.E, Gittenberger-de Groot, A.C, & Wladimiroff, J.W. (2001). Dorsal aortic flow velocity in chick embryos of stage 16 to 28. Ultrasound in Medicine & Biology, 27(7), 919–924. doi:10.1016/S0301-5629(01)00393-3