Oxygen saturation in E14 mouse embryo and placenta

In vivo coregisterd high-resolution ultrasound (greyscale) and photoacoustic (red, white and blue) image of an E14 embryo and its associated placenta (on left of each image).  The photoacoustic signal represents a parametric map of oxygen saturation with red values representing higher sO2.  The image was acquired while the mother was breathing medical air (20% O2).  Oxygen saturation can be distinguished within differing placental and embryonic anatomy.