What is ultrasound?

  • (noun): Very high frequency sound; used in ultrasonography.
    See also — Additional definitions below


Ultrasound is a cyclic sound pressure wave with a frequency greater than the upper limit of the human hearing range. Ultrasound is thus not separated from "normal" (audible) sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is approximately 20 kilohertz (20,000 hertz) in healthy, young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.

Read more about Ultrasound.

Some articles on ultrasound:

Acoustic Targeted Drug Delivery - How ATDD Works
... Focused ultrasound similar to High intensity focused ultrasound, but at much lower powers is applied to tissues in conjunction with the local application ... The ultrasound source (or transducer) is pulsed on and off, and moved in a defined pattern to sonicate the tissue of interest ... The pulsing of the ultrasound serves two purposes 1 ...
Ultrasound - Safety
... Occupational exposure to ultrasound in excess of 120 dB may lead to hearing loss ... This report recommended an exposure limit for the general public to airborne ultrasound sound pressure levels (SPL) of 70 dB (at 20 kHz), and 100 dB (at 25 kHz and above) ...
Acoustic Microscopy - Behavior of Ultrasound in Materials
... Ultrasound is broadly defined as any sound having a frequency above 20 kHz, which is approximately the highest frequency that can be detected by the human ear ... However, the acoustic microscopes emit ultrasound ranging from 5 MHz to beyond 400 MHz so that micrometre size resolution can be achieved ... The ultrasound that penetrates a sample may be scattered, absorbed or reflected by the internal features or the material itself ...
Cirrhosis - Diagnosis - Imaging
... Ultrasound is routinely used in the evaluation of cirrhosis, where it may show a small and nodular liver in advanced cirrhosis along with increased echogenicity with irregular appearing areas ... Ultrasound may also screen for hepatocellular carcinoma, portal hypertension and Budd-Chiari syndrome (by assessing flow in the hepatic vein) ... The FibroScan produces an ultrasound image of the liver (from 20–80 mm) along with a pressure reading (in kPa) ...
American Institute Of Ultrasound In Medicine
... The American Institute of Ultrasound in Medicine is a multidisciplinary association dedicated to advancing the use of ultrasound in medicine through ... physicians, scientists, engineers, other health care providers, manufacturers of ultrasound equipment, and students ... and a Council on Sections, representing many ultrasound specialties ...

More definitions of "ultrasound":

  • (noun): Using the reflections of high-frequency sound waves to construct an image of a body organ (a sonogram); commonly used to observe fetal growth or study bodily organs.
    Synonyms: sonography, ultrasonography