In A-mode, the strength of the echo signal is represented by which feature?

In A-mode, the strength of the echo signal is represented by which feature?

• A. The brightness of the dot
• B. The brightness of the spike
• C. The distance between two spikes
• D. The height of the spike

Answer: (D)

In A-mode ultrasound, echoes appear as spikes, and the height of each spike encodes how strong that echo is—the amplitude of the returning signal. A stronger reflection from a tissue interface produces a taller spike, while a weaker reflection yields a shorter one. The horizontal position of the spike marks depth (time-of-flight), but the height specifically conveys echo strength. The idea of brightness isn’t used in A-mode (that pertains to other modes like B-mode), and the distance between spikes reflects spacing of reflectors in depth, not their strength. So the height of the spike best represents the echo strength.

In A-mode ultrasound, echoes appear as spikes, and the height of each spike encodes how strong that echo is—the amplitude of the returning signal. A stronger reflection from a tissue interface produces a taller spike, while a weaker reflection yields a shorter one. The horizontal position of the spike marks depth (time-of-flight), but the height specifically conveys echo strength. The idea of brightness isn’t used in A-mode (that pertains to other modes like B-mode), and the distance between spikes reflects spacing of reflectors in depth, not their strength. So the height of the spike best represents the echo strength.