Emergency Ultrasound > Technique > Terms

Technique - Terms

Anechoic lacking internal echoes.

Acoustic Enhancement occurs when sound passes through an anechoic structure. No echoes are reflected and so they are all available to pass through. More echoes are seen deep to the anechoic structure because more sound is available.


Image of a large renal cyst shows the classic findings of a simple cyst.  The fluid contents are anechoic (red arrow), the walls are thin and sharply defined, and acoustic enhancement (E) is evident deep to the cyst.s


Acoustic Shadowing occurs when the sound wave encounters a very echo dense structure, nearly all of the sound is reflected, resulting in an acoustic shadow.

Gallstone (red arrow) within the the gallbladder produces a bright echo and causes a dark acoustic shadow (S).


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