Which statement best describes attenuation in soft tissue?

Which statement best describes attenuation in soft tissue?

• A. Intermediate
• B. Low
• C. High
• D. Extremely high

Answer: (A)

Attenuation is the loss of ultrasound energy as the beam travels through tissue, caused by absorption, scattering, and sometimes reflection. In soft tissue this loss is moderate, not minimal and not extreme—that's why it’s described as intermediate attenuation. The soft-tissue attenuation coefficient is about 0.5 dB per centimeter per megahertz, so higher-frequency beams lose more energy per centimeter, but the overall attenuation remains manageable for imaging many depths. This balance contrasts with bone, where attenuation is high due to the dense, absorptive nature of mineralized tissue, and with air, where attenuation is extremely high because of large impedance differences causing almost all energy to reflect. This intermediate level of attenuation helps explain why ultrasound works well for many soft-tissue exams while still requiring adjustments in frequency to optimize depth and resolution.

Attenuation is the loss of ultrasound energy as the beam travels through tissue, caused by absorption, scattering, and sometimes reflection. In soft tissue this loss is moderate, not minimal and not extreme—that's why it’s described as intermediate attenuation. The soft-tissue attenuation coefficient is about 0.5 dB per centimeter per megahertz, so higher-frequency beams lose more energy per centimeter, but the overall attenuation remains manageable for imaging many depths. This balance contrasts with bone, where attenuation is high due to the dense, absorptive nature of mineralized tissue, and with air, where attenuation is extremely high because of large impedance differences causing almost all energy to reflect. This intermediate level of attenuation helps explain why ultrasound works well for many soft-tissue exams while still requiring adjustments in frequency to optimize depth and resolution.