Energy in the form of sound waves is passed into the body. Reflected sound waves returning to the probe are used to create an image of the internal organs. Ultrasound studies are most helpful to evaluate soft tissue and fluid structures. Moving organs may be evaluated during motion, such as the beating heart, flowing blood and contracting intestines. Gastrointestinal foreign material may be identified on an ultrasound exam when it is not apparent on radiographs. While radiographs are useful to assess organ size and overall shape, an ultrasound exam allows for evaluation of the organ architecture and blood supply. Ultrasound examinations are commonly performed on the abdomen, thorax, neck, eyes and soft tissue structures of the head, trunk and legs. In addition to assessment of organ architecture, ultrasound examination is helpful to identify free fluid within a body cavity (i.e., thorax and abdomen).
ULTRASOUND GUIDED ASPIRATE AND CORE BIOPSY, INCLUDING ABDOMINOCENTESIS AND THORACOCENTESIS
Following assessment of an organ and the surrounding structures, ultrasound imaging is used to guide needle placement into a selected tissue or cavity. A sample of tissue or fluid may be drawn through the needle as an aspirate to analyze the cells or other contents of the sample (cytology and microbiology). A larger needle may be used to retrieve a small piece of solid tissue for a core-biopsy to analyze the architecture of the tissue (histopathology). Ultrasound guidance is commonly used to removing fluid from the chest cavity (thoracocentesis) and abdominal cavity (abdominocentesis).