Ultrasound works by transmitting ultrasound waves and detecting the waves that bounce back from structures live images of soft tissue, vasculature, and organs are reconstructed. By using the doppler effect it is possible to measure to direction and speed of blood flow in blood vessels and the heart. Ultrasound is preferred for many applications due to its quick, real-time imaging with no required contrast agents or radiation. The pre-clinical ultrasound systems utilize high frequency to resolve small structures in rodents, including 6.5 days-old embryos.
