Which statement about lateral resolution is NOT true?

Which statement about lateral resolution is NOT true?

• A. It is equal to beam width.
• B. It is improved by focusing.
• C. It is defined as the minimum separation required to resolve two structures perpendicular to the beam axis.
• D. It remains constant throughout scanning depth.

Answer: (D)

Lateral resolution hinges on how wide the ultrasound beam is across its path. The narrower the beam, the closer two structures side by side can be before they blur together. Focus sharpens the beam in the focal zone, reducing its width and thus improving lateral resolution there. By definition, lateral resolution is the minimum lateral separation needed to distinguish two structures perpendicular to the beam axis, which ties directly to that beam width at the depth of interest. It does not stay constant with depth because the beam broadens as it travels away from the focus, so lateral resolution improves at the focus and degrades outside of it. That makes the statement about remaining constant throughout scanning depth not true.

Lateral resolution hinges on how wide the ultrasound beam is across its path. The narrower the beam, the closer two structures side by side can be before they blur together. Focus sharpens the beam in the focal zone, reducing its width and thus improving lateral resolution there. By definition, lateral resolution is the minimum lateral separation needed to distinguish two structures perpendicular to the beam axis, which ties directly to that beam width at the depth of interest. It does not stay constant with depth because the beam broadens as it travels away from the focus, so lateral resolution improves at the focus and degrades outside of it. That makes the statement about remaining constant throughout scanning depth not true.