Which statement about A-mode displays is true?

Which statement about A-mode displays is true?

• A. It Shows a Two-Dimensional Gray-Scale Image
• B. It Shows Depth Along a Single Line as Spikes
• C. It Displays Moving Structures Over Time
• D. It Measures Frequency Shifts

Answer: (B)

A-mode displays present a one-dimensional profile where echoes along a single scan line appear as vertical spikes. The horizontal position of each spike corresponds to depth (time-of-flight from emission to echo), and the spike height reflects the echo strength. This creates a line of spikes rather than a 2D gray-scale image or a motion sequence. In contrast, a 2D gray-scale image comes from B-mode, moving structures over time are shown in M-mode, and frequency shifts are the domain of Doppler ultrasound. So the true statement is that depth along a single line is shown as spikes.

A-mode displays present a one-dimensional profile where echoes along a single scan line appear as vertical spikes. The horizontal position of each spike corresponds to depth (time-of-flight from emission to echo), and the spike height reflects the echo strength. This creates a line of spikes rather than a 2D gray-scale image or a motion sequence. In contrast, a 2D gray-scale image comes from B-mode, moving structures over time are shown in M-mode, and frequency shifts are the domain of Doppler ultrasound. So the true statement is that depth along a single line is shown as spikes.