Fig. 1: Experimental set-up for contrast-enhanced ultrasound (CEUS) of the brain.

a Illustration depicting the fetal lamb within the EXTrauterine Environment for Neonatal Development (EXTEND) undergoing CEUS of the brain with US contrast administered into the fetal circulation (syringe) distal to the oxygenator with imaging performed of the fetal brain. b Representative transaxial image through the fetal lamb brain at peak enhancement during CEUS examination with regions of interest (ROI) including whole brain (red circle), central/thalamic region (T), and peripheral parenchyma (P).