Metabolic and Anatomic Development of the Chick Embryo As Studied by Phosphorus-31 Magnetic Resonance Spectroscopy and Proton MRI

Thirty fertilized chick eggs were studied sequentially over the 22-day maturation period of the egg by phosphorous-31 (P-31) magnetic resonance spectroscopy (MRS) and proton (H-1) magnetic resonance imaging (MRI) at 2.0 Tesla. The total MR observable P-31 volume in the egg decreased by nearly 80% from day 4 through day 22, suggesting P-31 uptake into tissues in which the P-31 signal is not visible by MR, such as phospholipid bilayers, membranes, cellular structures, and bone mineral phosphates. Of the remaining visible phosphates, the relative phospholipid peak area decreased and the relative peak areas of the phosphocreatine and nucleoside di- and triphosphate metabolites increased. Inorganic phosphate also showed an increase in peak area during maturation. The metabolic development correlated with the anatomic development of visible structures such as brain, eyes, spine and organs in the chick as seen by MRI. In-vivo MR techniques offers the potential to follow changes in prenatal development and maturation.