Three-dimensional magnetic resonance microscopy of the developing chick embryo.

Magnetic resonance imaging microscopy was performed on live chick embryos. A combination of high gradient strength (0.47 mT/cm), special purpose radiofrequency coils and 3-dimensional Fourier imaging was used to obtain images with effective thickness of 1.25 mm and pixel dimensions as small as 200 mu in the live chick embryo. The signal-to-noise ratio was sufficient to allow unequivocal identification of the individual chambers of the heart, spinal cord, ventricles in the brain, and vascular structures in the liver of a live 11-day embryo. Anatomical assignment was accomplished with the aid of correlated histologic sections. Because there are no external landmarks, the plane of imaging is frequently oblique, making the 3-dimensional acquisition particularly useful.