Higher frequency yields better axial resolution but higher attenuation with depth.

• A. Improves axial resolution but increases attenuation with depth
• B. Improves lateral resolution but reduces near-field imaging
• C. Increases beam width and decreases image quality
• D. Has no effect on resolution or attenuation

Answer: (A)

Higher frequency improves axial resolution because the spatial pulse length becomes shorter at higher frequencies, so two reflectors that are close together along the beam path can be distinguished more clearly. At the same time, higher frequency experiences greater attenuation in tissue due to more absorption and scattering, which limits how deep the ultrasound can effectively penetrate. So you get crisper detail along the beam axis for superficial structures, but you sacrifice depth penetration. Lateral resolution and near-field imaging depend more on beam width and focusing, not just frequency, so the key trade-off described here is about axial detail versus depth reach.