Ultrasound is a diagnostic imaging tool that allows us to look within tissues.
An x-ray provides information about various parts of the body. An ultrasound is usually used to view a specific organ or set of organs to help doctors examine and diagnose. X-rays show the overall size and appearance of organs and body structures, but ultrasound can show us the internal structures. Often abnormalities found on x-rays will be investigated further using ultrasound. Another favorite use of the ultrasound is to detect pregnancy before it shows up on X-ray !
Any animal where an abnormality such as an enlarged organ or mass is found on examination or x-rays can benefit from ultrasound to better assess the abnormality. Ultrasound can also be used to evaluate viability of pregnancy and aid in the collection of samples such as urine or other body fluid.