What is the term for multiple echoes received at the same time causing a grainy appearance on the display?

• A. Reflection angle
• B. Refraction
• C. Speckle
• D. Specular reflections

Answer: (C)

Speckle is the grainy look on ultrasound images caused by the coherent interference of many backscattered echoes from numerous tiny structures within the tissue. Each microstructure reflects sound with varying phase and amplitude, and when those echoes arrive together at the same image location, they sum in a way that produces a random, granular pattern. This speckle is inherent to B‑mode ultrasound and can both obscure subtle features and provide textural information. It’s not due to a single smooth-surface reflection, abrupt bending of the beam (refraction), or a particular reflection angle—the graininess comes from the collective interference of many echoes. Techniques like spatial compounding or other processing can reduce speckle, but it can’t be completely eliminated.