An ultrasound test, also known as sonography, uses high-frequency sound waves to create real-time images of the inside of the body. It is a non-invasive and safe imaging technique that helps doctors visualize and diagnose various medical conditions. Ultrasound is commonly used for imaging the abdomen, pelvis, heart, blood vessels, and developing fetuses during pregnancy. It can also be used to guide medical procedures such as biopsies or injections.