What is the effect of decreasing pulse duration on axial resolution?

• A. Decreases axial resolution
• B. Has no effect on axial resolution
• C. Improves axial resolution
• D. Only affects lateral resolution

Answer: (C)

Shorter pulse duration shortens the spatial length of the ultrasound burst, so the distance over which echoes are generated becomes smaller. Axial resolution is approximately half the spatial pulse length, meaning that a shorter spatial pulse length lets you distinguish structures that are closer together along the beam path. Therefore, decreasing pulse duration improves axial resolution.

It doesn’t change lateral resolution, which is determined by the beam width across the image, not by the pulse duration.