In B-mode, the z-axis represents what?

In B-mode, the z-axis represents what?

• A. Depth
• B. Amplitude
• C. Time
• D. Nothing

Answer: (B)

In B-mode ultrasound, what you see on the screen is a map where the brightness of each point encodes how strong the echo was from that location. That echo strength is the amplitude. So if you think of a z-axis representing a third dimension, it corresponds to the amplitude information—the brighter the pixel, the larger the echo amplitude. The actual depth of structures is shown along the vertical (and horizontal) positions on the image, not as the z-axis. Time isn’t an axis on the displayed image either.

In B-mode ultrasound, what you see on the screen is a map where the brightness of each point encodes how strong the echo was from that location. That echo strength is the amplitude. So if you think of a z-axis representing a third dimension, it corresponds to the amplitude information—the brighter the pixel, the larger the echo amplitude. The actual depth of structures is shown along the vertical (and horizontal) positions on the image, not as the z-axis. Time isn’t an axis on the displayed image either.