Which statement about ultrasound frequency and resolution is true?

• A. Higher frequency provides deeper penetration but poorer resolution
• B. Higher frequency provides better resolution with deeper penetration
• C. Higher frequency provides better resolution but shallower penetration
• D. Frequency does not affect resolution

Answer: (C)

Ultrasound frequency controls a trade-off between image detail and depth of penetration. Higher frequency waves have shorter wavelengths, which improves the system’s ability to distinguish closely spaced structures, yielding better resolution. At the same time, these higher-frequency waves are attenuated more quickly by tissue, so they don’t travel as far. That’s why a higher frequency provides better resolution but shallower penetration. In practice, clinicians choose a high-frequency probe for superficial structures and a lower-frequency probe for deeper ones.