Which scanning mode does NOT rely on the principle of echo ranging to determine interface location?

Which scanning mode does NOT rely on the principle of echo ranging to determine interface location?

• A. M-Mode
• B. Pulsed-Wave Doppler
• C. Static B-Mode
• D. Transmission

Answer: (D)

Understanding how interfaces are located in ultrasound hinges on echo-ranging—the time it takes for a pulse to travel to a boundary and back, using that time with the speed of sound to map depth. M-mode follows echoes along a single line over time to track the depth of interfaces, while static B-mode builds a two-dimensional map from echoes at different depths. Pulsed-wave Doppler uses echoes to sample a specific depth and measure velocity, again relying on knowing where along the beam you’re measuring from. Transmission mode, by contrast, analyzes the energy that passes through tissue rather than reflections to create a spatial map, so it does not determine interface location via echo ranging.

Understanding how interfaces are located in ultrasound hinges on echo-ranging—the time it takes for a pulse to travel to a boundary and back, using that time with the speed of sound to map depth. M-mode follows echoes along a single line over time to track the depth of interfaces, while static B-mode builds a two-dimensional map from echoes at different depths. Pulsed-wave Doppler uses echoes to sample a specific depth and measure velocity, again relying on knowing where along the beam you’re measuring from. Transmission mode, by contrast, analyzes the energy that passes through tissue rather than reflections to create a spatial map, so it does not determine interface location via echo ranging.