Which is an advantage of coded excitation in ultrasound imaging?

• A. Improved lateral resolution
• B. Improved contrast resolution
• C. Improved temporal resolution
• D. Shorter pulse repetition period

Answer: (B)

Coded excitation sends a longer, energy-rich pulse and then compresses it on receive, so more energy reaches the tissue without increasing the peak transmit intensity. This boosts the signal-to-noise ratio of the echoes, making weak or subtle echoes more detectable. With higher SNR, differences between tissues become more apparent, which enhances the ability to distinguish one tissue from another — that is, better contrast resolution. Lateral resolution relies on beam width and focusing, temporal resolution on frame rate and PRF, and the technique doesn’t inherently shorten the pulse repetition period, so those aspects aren’t the primary advantage.