Ultrasound looks inside the body through a different non-invasive technology than radiology (xrays), and the two imaging techniques often complement one another. When your pet undergoes an ultrasound, an area will be shaved and a probe placed on the skin. Because an ultrasound study usually takes 30 minutes or so, patients are usually given a mild tranquilizer or sedative to help them relax and remain still for the procedure. Depending on the particular area being visualized, and why, the images (both still and video) may be sent electronically to be viewed and interpreted by a radiologist.