What is the speed of sound in blood tissue?

• A. 1,560 m/s
• B. 1,600 m/s
• C. 1,700 m/s
• D. 3,500 m/s

Answer: (A)

The speed of sound in tissues is determined by how compressible the tissue is and how dense it is. Blood behaves very much like soft tissue in these properties, so its acoustic velocity is close to that of soft tissue. The commonly used value for soft tissue is about 1,540 m/s, and blood is typically cited around 1,560 m/s. Ultrasound systems often use this standard 1,540–1,560 m/s range when converting round‑trip travel time to depth, so 1,560 m/s is the best estimate for blood tissue.

The other numbers correspond to different tissues: 3,500 m/s is characteristic of bone, which is far faster; 1,700 m/s and 1,600 m/s are less representative for blood compared with the standard soft-tissue value.