What appearance does a cyst typically have on ultrasound?

What appearance does a cyst typically have on ultrasound?

• A. Anechoic
• B. Hyperechoic
• C. Isoechoic
• D. Hypoechoic

Answer: (A)

Fluid-filled cysts appear anechoic on ultrasound, meaning they look completely black on the gray-scale image. This occurs because the fluid content reflects very few echoes back to the transducer. A simple cyst also often has a thin, well-defined wall and shows posterior acoustic enhancement, where the area behind the cyst looks brighter due to transmission of sound through the fluid with little attenuation. If a cyst isn’t simple—such as when it contains debris, blood, or infection—it may develop internal echoes and no longer appear completely anechoic.

Fluid-filled cysts appear anechoic on ultrasound, meaning they look completely black on the gray-scale image. This occurs because the fluid content reflects very few echoes back to the transducer. A simple cyst also often has a thin, well-defined wall and shows posterior acoustic enhancement, where the area behind the cyst looks brighter due to transmission of sound through the fluid with little attenuation. If a cyst isn’t simple—such as when it contains debris, blood, or infection—it may develop internal echoes and no longer appear completely anechoic.