Which statement correctly describes the relationship between pixel size and spatial resolution?

• A. Larger pixel size yields higher spatial resolution
• B. Smaller pixel size yields higher spatial resolution
• C. Pixel size does not affect spatial resolution
• D. Spatial resolution depends only on exposure

Answer: (B)

Smaller pixel size means the image is sampled more finely. Spatial resolution reflects how well nearby details can be distinguished, and finer sampling with smaller pixels captures more detail, allowing two close structures to appear as separate features rather than being blurred together. If pixels are large, each one averages over a bigger area, which smooths out small details and reduces the ability to separate closely spaced structures.

In mammography, this is why detectors with small pixel pitch can show tiny features like microcalcifications more clearly. But keep in mind that smaller pixels also collect fewer photons per pixel, which can increase noise unless the exposure is increased or dose is managed. The other statements don’t fit because enlarging the pixel size does not improve detail, and spatial resolution isn’t determined solely by exposure—the sampling grid and detector design play crucial roles.