An ultrasound test uses reflected sound waves to produce a picture of organs and other structures inside the body. It does not use X-rays or other types of radiation.

During an ultrasound test, a small handheld instrument called a transducer (that emits and detects high-pitched sounds beyond the range of human hearing) is passed back and forth over the area of the pet’s body being examined. A computer analyzes the sound waves that are reflected back from structures inside the pet’s body. These reflected sound waves are converted into a picture and displayed on a video monitor. The images produced by ultrasound are called a sonogram, echogram, or scan. Pictures or videos of the ultrasound images may be saved for a permanent record.

Ultrasound is most useful for looking at organs and structures that are either uniform and solid (like the liver) or fluid-filled (like the bladder). Mineralized structures (like bones) or air-filled organs (like the lungs) do not show up well on a sonogram.