Ultrasonography is a unique non-invasive tool available  to ascertain the appearance of the internal organs. This tool is especially useful for visualizing the shape and structure of soft tissues that cannot be easily seen on radiographs. Ultrasound can be used to survey the abdominal organs to help diagnose an issue, or as a guide while performing procedures such as cystocentesis (the withdrawing of urine from the bladder via a needle), or needle tissue biopsy.

Example of a still image of a mass: