Category: 4. Basic Ultrasound Terminology: “Echogenicity”

The term “Isoechoic” on ultrasound means that a specific structure gives off similar echoes relative to another structure on the ultrasound screen. For example, you may say the Renal Cortex is isoechoic to the Spleen Parenchyma like the image below:

The term “Hypoechoic” on ultrasound means that a specific structure gives off fewer echoes relative to it’s surrounding structures resulting in a darker or more grey appearance.

In the image below this patient has hepatitis with a Hypoechoic (darker) appearing liver compared to the right kidney:

The term “Hyperechoic” on ultrasound means that a specific structure gives off MORE echoes relative to it’s surrounding structures resulting in a brighter/whiter appearance. Below is an example of the pleural line which is “Hyperechoic” (bright/white) compared to the surrounding soft tissue.

The term “Anechoic” on ultrasound means no internal echoes are emitted and there is a completely black appearance. This is most commonly seen with fluid-filled structures since ultrasound waves pass through fluid without reflecting any echoes back to the ultrasound machine.

Here is a list of structures that appear “Anechoic” or black on ultrasound: blood (unclotted), bladder, transudative pleural effusions, ascites, simple cysts, gallbladder.

So if you want to speak the “language” of ultrasound, you will need to refer to specific structures on an ultrasound image based on it’s “Echogenicity.”

“Echogenicity” refers to how bright (echogenic) a tissue appears on ultrasound relative to another tissue.