Sonography is a diagnostic medical test that uses high-frequency sound waves—also called ultrasound waves—to bounce off of structures in the body and create an image. The test is often referred to simply as an ultrasound or as a sonogram.

Sonography uses a device called a transducer to send out ultrasound waves and listen for the echo. A computer translates the ultrasound waves into an image. A trained technician can see, measure, and identify structures in the image. A specially trained physician then reads the images to help diagnose medical conditions.