Which factor LEAST influences lateral resolution?

Which factor LEAST influences lateral resolution?

• A. Frequency
• B. Focus depth
• C. Beam width
• D. Damping

Answer: (D)

Lateral resolution depends on how narrow the ultrasound beam is in the plane perpendicular to the direction of travel at the depth of interest. The narrower that beam, the better two side-by-side structures can be distinguished. Higher frequency helps because shorter wavelengths allow the beam to be more tightly focused, reducing beam width in the focal region. Focus depth directly shapes where the beam is narrowest, so adjusting the focal depth improves lateral resolution at that depth. Beam width itself is the immediate determinant of lateral resolution—the tighter the beam, the better the lateral detail. Damping mainly affects the duration and bandwidth of the pulse, which improves axial resolution (along the direction of the beam) and temporal response, but it does not strongly change the width of the beam across the imaging plane. Therefore damping has the least influence on lateral resolution.

Lateral resolution depends on how narrow the ultrasound beam is in the plane perpendicular to the direction of travel at the depth of interest. The narrower that beam, the better two side-by-side structures can be distinguished.

Higher frequency helps because shorter wavelengths allow the beam to be more tightly focused, reducing beam width in the focal region. Focus depth directly shapes where the beam is narrowest, so adjusting the focal depth improves lateral resolution at that depth. Beam width itself is the immediate determinant of lateral resolution—the tighter the beam, the better the lateral detail.

Damping mainly affects the duration and bandwidth of the pulse, which improves axial resolution (along the direction of the beam) and temporal response, but it does not strongly change the width of the beam across the imaging plane. Therefore damping has the least influence on lateral resolution.