Which statement correctly describes the effect of beam width on lateral resolution?

Which statement correctly describes the effect of beam width on lateral resolution?

• A. Wider beam width improves lateral resolution
• B. Narrower beam width improves lateral resolution
• C. Beam width has no effect on lateral resolution
• D. Lateral resolution is determined by tissue density

Answer: (B)

Lateral resolution depends on how tightly the ultrasound energy is confined across the width of the beam. A narrower beam confines energy to a smaller lateral area, reducing spreading and blur, which allows two structures that are side by side to be distinguished more clearly. A wider beam, on the other hand, illuminates a broader region and increases lateral blur, making closely spaced structures harder to separate. So, narrowing the beam width directly improves lateral resolution. Tissue density and other tissue properties influence how sound travels and attenuates, but they don’t determine lateral resolution as the beam width does.

Lateral resolution depends on how tightly the ultrasound energy is confined across the width of the beam. A narrower beam confines energy to a smaller lateral area, reducing spreading and blur, which allows two structures that are side by side to be distinguished more clearly. A wider beam, on the other hand, illuminates a broader region and increases lateral blur, making closely spaced structures harder to separate. So, narrowing the beam width directly improves lateral resolution. Tissue density and other tissue properties influence how sound travels and attenuates, but they don’t determine lateral resolution as the beam width does.