VISUALIZATION OF ANISOTROPIC PULSATIONS IN EXTRAEMBRYONIC COMPARTMENTS OF INCUBATED QUAIL EGGS BY NMR MICROIMAGING

Multi-plane tagging time-of-flight and bipolar gradient phase-encoding and amplitude-weighting NMR microimaging techniques have been employe d to study transport in extraembryonic compartments of fertilized quai l eggs during the first seven days of incubation, After the fourth day coherent and incoherent motions became visible in certain regions, in particular in the upper part of the albumen. Coherent motions as visu alized by deformations of multiplane tagging grids were specified by l ocal velocities less than 1 mm/s at most. On the other hand, incoheren t motions led to much more pronounced phenomena. The multiplane taggin g grid completely faded in a region comprising the upper third of the albumen after 4.5 incubation days, Images weighted by signal attenuati on owing to incoherent displacements indicate motions in the same regi on, The fact that a reproducible localization of the motions is only p ossible when signals from different transients are averaged indicates that the incoherence at least partly is temporal in nature. The signal intensity of a volume selected in the incoherent-motion region conseq uently fluctuates with time. The Fourier analysis of these fluctuation s revealed a distinct pulsation with a frequency of 0.4 Hz. Copyright (C) 1996 Elsevier Science Inc.