Noninvasive monitoring of chick development in ovo using a 7T MRI system from day 12 of incubation through to hatching

Abstract

Purpose: To determine whether mild cooling of the egg reduces movement to the point where an ultra-high-field (7T) MRI system can be used to noninvasively monitor chick growth in ovo from 12 days incubation through to hatching. Materials and Methods:Group A eggs were incubated at 37.5°C for 21 days. Group B eggs were removed from the incubator on days 12, 15, 17, 18, 19, and 20 of incubation, cooled for one hour, and then returned to the incubator. Group C eggs were cooled as for group B and then individually imaged for 25 minutes using a 7T MRI system before being returned to the incubator. The average size (volume) of the heart, liver, and brain at each stage of incubation was estimated from the T 2 -weighted images and compared with existing values in the literature. Results:The combination of cooling and MRI significantly reduced chick movement to allow excellent image acquisition at each stage of incubation. Repeated cooling and/or MRI did not significantly slow down or arrest the development of the chicks in either of the experimental groups.Conclusion: MRI provides a powerful noninvasive tool to study chick development and the growth of individual organs, including the brain, liver, and heart, in ovo from 12 days' incubation.

Measurement of T1, T2, and magnetization transfer properties during embryonic development at 7 Tesla using the chicken model

“…Furthermore, the lack of breathing artifacts of the mother animal allows the application of relatively long acquisition times. Several studies reported the investigation of fertilized eggs using MRI (12)(13)(14)(15)(16)(17)(18). The mentioned studies mainly dealt with the follow up of anatomic development of the avian embryos.…”

3D Reconstruction of Chick Embryo Vascular Geometries Using Non-invasive High-Frequency Ultrasound for Computational Fluid Dynamics Studies

“…Bain et al utilized mild cooling to reduce the motion of the chick embryo, and assumed that the embryo was motion-free when scanning in ovo with a high-resolution 7T MRI system. 5 Holmes et al removed the need to gate with the embryo's heart rate by employing a self-gated scanning protocol that incorporated a navigator-based retrospective gating technique. 23 These techniques are less invasive than our technique, as the need to peel the egg shell open was removed.…”

Three-Dimensional (3D) Visualisation of the Cardiovascular System of Mouse Embryos and Fetus

“…They are either optimised for diagnosing pathologies in humans (computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), single photon emission computed tomography (SPECT), positron emission tomography (PET)), for in vivo analysis of -often transparent -model animals [23][24][25][26][27][28][29][30][31][32], or for post-mortem analyses of entire biological specimens and biological tissue samples, on the molecular, subcellular, cellular, tissue, and organ system level (atomic force microscopy, electron microscopy, confocal imaging, optical projection tomography (OPT), episcopic imaging techniques, histological sectioning, micro-MRI, micro-CT, near infrared imaging techniques, polarised light spectroscopy, optical coherence tomography (OCT)). Not all of these techniques permit 3D imaging of the developing cardiovascular system of unborn mice.…”