Calcified plaque on ultrasound typically shows which feature?

• A. Posterior acoustic shadowing
• B. Posterior enhancement
• C. Hypoechoic mass
• D. Acoustic streaming

Answer: (A)

Calcified plaque has high acoustic impedance and attenuates the ultrasound beam strongly. Because most of the energy is reflected at the calcium and little passes through, you see a dark shadow behind the plaque—posterior acoustic shadowing. This shadowing is a hallmark of calcification in vessels. Posterior enhancement would occur with fluid or cystic structures that have low attenuation, not with calcified tissue. A hypoechoic mass describes a dark, solid-appearing lesion, which isn’t typical for calcified plaque that usually appears bright (echogenic) with shadow. Acoustic streaming is a Doppler-related phenomenon, not a grayscale feature of calcified plaque.