The use of sound vibrations above the limits of human hearing to produce images with which to diagnose internal bodily conditions.
His doctor, who loved new technology, used CAT scans, MRI, and ultrasound to view his various organs.
The root son- came to be spelled soun- in medieval English, which led to sound and all the English words that now contain it. Ultrasound, or ultrasonography, works on the principle that sound is reflected at different speeds by tissues of substances of different densities. Sonograms, the pictures produced by ultrasound, can reveal heart defects, tumors, and gallstones, but are most often used to display fetuses during pregnancy in order to make sure they are healthy.