Ultrasound is like ordinary sound except it has a frequency higher than humans can hear. The sound is reflected off of internal structures. The returning echoes are then received by the transducer and converted by an electronic instrument into an image on a monitor. The images can be printed or recorded. Ultrasound imaging allows doctors to look inside your pet’s body, and thus help observe the structure and function of the heart, locate abdominal tumors, visualize the liver and spleen, or even look inside the bladder.