Which term refers to tissue that has the same brightness as surrounding tissue?

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

Answer: (A)

Understanding ultrasound brightness, or echogenicity, is key. Isoechoic describes tissues that echo with the same intensity as surrounding tissue, so on the image they appear the same shade of gray. That makes the tissue blend in rather than stand out. The correct term for tissue that matches surrounding brightness is isoechoic. If a structure were darker than its surroundings, it would be hypoechoic, indicating fewer echoes. If it were completely dark with no echoes, it would be anechoic, as seen with fluid-filled structures. If it were brighter than surrounding tissue, it would be hyperechoic, reflecting more echoes, such as calcifications or fibrous tissue. In practice, recognizing isoechoic areas helps us understand when a lesion may be difficult to distinguish from normal tissue because they have similar echogenicity.