Ultrasonography is a diagnostic imaging technique that uses high-frequency sound waves to create images of internal organs and tissues within the body. It's also commonly referred to as ultrasound or sonography, which involves using a transducer (a small handheld device) that emits pulses of sound energy and then detects the echoes produced by the sound waves when they bounce off internal structures in the body. The data collected is then used to create real-time images on a monitor, allowing physicians to visualize and analyze organs such as the heart, liver, kidneys or blood vessels, without invasive procedures. Ultrasonography is widely used during pregnancy to examine the developing fetus, but it can also be employed for various other diagnostic purposes in different medical fields including cardiology, neurology, and gynecology among others.