Among B-mode, gray-scale imaging, continuous-wave Doppler, and pulsed Doppler, which has the greatest output intensity?

Among B-mode, gray-scale imaging, continuous-wave Doppler, and pulsed Doppler, which has the greatest output intensity?

• A. Pulsed Doppler
• B. B-mode
• C. Gray scale imaging
• D. CW Doppler

Answer: (A)

The key idea is how energy is delivered over time. Output intensity refers to the power emitted by the transducer during transmission, and a mode that channels energy into short, high-energy bursts will have higher instantaneous intensity than modes that emit more continuously or with lower per-pulse energy. Pulsed Doppler sends brief, high-energy bursts to sample Doppler shifts, so the peak acoustic intensity during each pulse is quite high. B-mode and gray-scale imaging rely on shorter bursts designed to form a grayscale image with lower per-pulse energy, giving lower peak intensity. Continuous-wave Doppler, while it transmits constantly, distributes energy over time rather than concentrating it into a short high-energy pulse, so its instantaneous intensity at any moment isn’t higher than the pulsed burst’s peak. Thus, the pulsed Doppler mode yields the greatest output intensity during its pulses.

The key idea is how energy is delivered over time. Output intensity refers to the power emitted by the transducer during transmission, and a mode that channels energy into short, high-energy bursts will have higher instantaneous intensity than modes that emit more continuously or with lower per-pulse energy.

Pulsed Doppler sends brief, high-energy bursts to sample Doppler shifts, so the peak acoustic intensity during each pulse is quite high. B-mode and gray-scale imaging rely on shorter bursts designed to form a grayscale image with lower per-pulse energy, giving lower peak intensity. Continuous-wave Doppler, while it transmits constantly, distributes energy over time rather than concentrating it into a short high-energy pulse, so its instantaneous intensity at any moment isn’t higher than the pulsed burst’s peak. Thus, the pulsed Doppler mode yields the greatest output intensity during its pulses.