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


METHODS
Group A eggs were incubated at 37.5 degrees 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 T2-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.


CONCLUSIONS
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.
Division of Cell Sciences, Institute of Comparative Medicine (ICM), University of Glasgow Veterinary School, Glasgow, Scotland, United Kingdom. m.bain@vet.gla.ac.uk
Maureen M
MM
Bain
Andrew J
AJ
Fagan
James M
JM
Mullin
Iain
I
McNaught
John
J
McLean
Barrie
B
Condon
D000818:Animals; D002642:Chick Embryo / Q000502:physiology*; D002645:Chickens; D003080:Cold Temperature; D047108:Embryonic Development / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D013696:Temperature