Which factor determines the brightness of a single dot on a B-mode display?

Which factor determines the brightness of a single dot on a B-mode display?

• A. Amplitude Of The Returning Echo
• B. Depth Of Reflector
• C. Doppler Shift
• D. Speed Of Sound

Answer: (A)

Brightness on a B-mode image reflects the strength of the returning echo—that is, the amplitude of the echo. When the ultrasound pulse hits an interface with a large impedance mismatch, more energy is reflected back, producing a brighter dot. If the echo is weaker, the dot appears dimmer. Depth only changes where the dot appears on the screen, not how bright it is, though deeper targets can seem dimmer due to attenuation. Doppler shift pertains to motion and is used in Doppler imaging, not to brightness in B-mode, and the speed of sound mainly affects how depth is mapped rather than the brightness of individual dots.

Brightness on a B-mode image reflects the strength of the returning echo—that is, the amplitude of the echo. When the ultrasound pulse hits an interface with a large impedance mismatch, more energy is reflected back, producing a brighter dot. If the echo is weaker, the dot appears dimmer. Depth only changes where the dot appears on the screen, not how bright it is, though deeper targets can seem dimmer due to attenuation. Doppler shift pertains to motion and is used in Doppler imaging, not to brightness in B-mode, and the speed of sound mainly affects how depth is mapped rather than the brightness of individual dots.