Which change would most likely decrease spatial resolution?

• A. Increased Matrix Size
• B. Increased Bit Depth
• C. Increased Contrast Resolution
• D. Increased Pixel Size

Answer: (D)

Spatial resolution is about how finely an image can show details—the ability to separate two close structures. In digital radiography, this depends on how small each pixel is and how many samples cover the image field. If you increase the pixel size, you have fewer pixels across the same field of view, so each pixel covers a larger area and fine details get smoothed out. That means the image loses sharpness and you can’t distinguish small features as well, which is a decrease in spatial resolution.

Other changes affect different aspects: increasing matrix size makes pixels smaller (improving spatial resolution when the field of view stays the same), increasing bit depth improves gray-scale information but not spatial detail, and increasing contrast resolution enhances the ability to differentiate shades of gray rather than separate tiny spatial features.