Spatial resolution is directly related to which factor related to the scan lines?

• A. Number of scan lines
• B. Beam frequency
• C. Transducer temperature
• D. Doppler shift

Answer: (A)

Spatial resolution is about how clearly two nearby structures can be separated in the image. When we talk about the imaging plane, the lateral (side-to-side) detail depends on how finely the image is sampled across that plane. The scan lines determine this sampling density: more scan lines mean the image is built from more sampling points across the width, giving finer lateral sampling and better ability to distinguish adjacent structures. So the number of scan lines directly affects how well we resolve detail across the image width.

Beam frequency, on the other hand, mainly influences axial resolution (depth direction) because higher frequency yields shorter wavelengths and sharper depth detail. Transducer temperature does not set spatial detail in standard imaging, and Doppler shift relates to motion/velocity information rather than static spatial resolution.