Which tissue type has propagation speed closest to soft tissue?

Which tissue type has propagation speed closest to soft tissue?

• A. muscle
• B. fat
• C. bone
• D. air

Answer: (A)

Propagation speed in tissues reflects how stiff and dense the tissue is; ultrasound relies on these speeds to convert travel time into depth. Soft tissue is typically about 1540 m/s. Among the options, muscle runs around 1580 m/s, which is very close to soft tissue, making it the closest match. Fat is slower (roughly 1450 m/s), bone is much faster (several thousand m/s), and air is far slower (about 343 m/s). Because muscle’s speed is nearest to soft-tissue speed, it aligns best with the reference value used for imaging.

Propagation speed in tissues reflects how stiff and dense the tissue is; ultrasound relies on these speeds to convert travel time into depth. Soft tissue is typically about 1540 m/s. Among the options, muscle runs around 1580 m/s, which is very close to soft tissue, making it the closest match. Fat is slower (roughly 1450 m/s), bone is much faster (several thousand m/s), and air is far slower (about 343 m/s). Because muscle’s speed is nearest to soft-tissue speed, it aligns best with the reference value used for imaging.