Which artifact is commonly associated with gas bubbles and appears as a chain of echoes behind a reflector?

Which artifact is commonly associated with gas bubbles and appears as a chain of echoes behind a reflector?

• A. Ring Down
• B. Comet Tail
• C. Side Lobes
• D. Focal Banding

Answer: (A)

Gas bubbles in tissue can resonate with the transmitted ultrasound pulse, and that resonance creates a distinctive ringing signal that continues after the initial pulse. This ring-down effect appears as a chain of echoes that run directly behind a reflector along the path of the beam. The echoes are discrete and evenly spaced, giving the impression of a train of reflections that persist, which is characteristic of gas-bubble resonance. This is different from other artifacts: comet-tail shows a short, bright tail behind a strong reflector and is tied to closely spaced reverberations from that single object; side lobes arise from off-axis beams producing spurious echoes; and focal banding results from variations in sound speed that cause brightness changes at the focus. The chain of evenly spaced echoes trailing behind a reflector is the hallmark sign of ring-down due to gas bubbles.

Gas bubbles in tissue can resonate with the transmitted ultrasound pulse, and that resonance creates a distinctive ringing signal that continues after the initial pulse. This ring-down effect appears as a chain of echoes that run directly behind a reflector along the path of the beam. The echoes are discrete and evenly spaced, giving the impression of a train of reflections that persist, which is characteristic of gas-bubble resonance.

This is different from other artifacts: comet-tail shows a short, bright tail behind a strong reflector and is tied to closely spaced reverberations from that single object; side lobes arise from off-axis beams producing spurious echoes; and focal banding results from variations in sound speed that cause brightness changes at the focus. The chain of evenly spaced echoes trailing behind a reflector is the hallmark sign of ring-down due to gas bubbles.