Increasing the number of acoustic scan lines in one frame generally leads to which improvement?

• A. Better lateral resolution
• B. Higher frame rate
• C. Higher temporal resolution
• D. Higher axial resolution

Answer: (A)

Increasing the number of scan lines per frame boosts lateral sampling density across the image. With more lines, the spacing between samples in the lateral direction becomes finer, so two reflectors that are close together side-by-side can be distinguished more clearly. This directly enhances lateral resolution, which is the ability to separate objects along the image width.

Axial resolution, determined by the wavelength and pulse length, isn’t changed by adding scan lines. Temporal resolution (frame rate) typically decreases when more lines are used, because more data must be acquired for each frame. So while frame rate and, hence, temporal resolution may worsen, the improvement you gain with more scan lines is in the image’s lateral detail.