MAGNETIC-RESONANCE-IMAGING (H-1) AND SPECTROSCOPY (H-1, P-31) OF GROWING CHICKEN EMBRYOS

Nuclear magnetic resonance (NMR) imaging and spectroscopy techniques were used to observe in vivo anatomical and metabolite changes, respectively, in developing chicken embryos. Proton (H-1) NMR images of the eggs revealed major changes in yolk shape from day 2 to day 6. Embryos were visible from day 6 to hatching, and good embryonic anatomical images were obtained. Two peaks were observed from H-1-NMR spectroscopy of fertilized eggs: one for lipid methylene protons, and one for water protons. Water peak to lipid peak ratios did not vary significantly (P > 0.05) from day 2 to dat 21 of incubation. Localized P-31-NMR spectra of developing embryos were obtained with either a P-31 surface coil or a double-tuned P-31/H-1 volume coil. The surface-coil method gave a greater signal to noise ratio by a factor of four. The P-31-NMR spectra indicated two peaks at day 2; these were attributed to phosphomonoesters and phosphodiesters. The three peaks characteristic of ATP appeared on day 11 and increased in size until hatching. From day 19, phosphocreatine was detectable. There appeared to be a good correlation between P-31-metabolite changes detected by in ViVo P-31-NMR spectroscopy and literature values for biochemical analyses of developing chicken embryos. The advantage in using NMR imaging and spectroscopy techniques is that anatomical and metabolic changes can be obtained in vivo, non-invasively and repeatedly as an embryo develops.