Which of the following adjustments can enhance image contrast?

Decreasing kVp (kilovolt peak) enhances image contrast because it reduces the energy of the x-rays produced. Lowering the kVp means that fewer high-energy x-rays will penetrate the thicker structures within the body while allowing the lower-energy x-rays to be absorbed by less dense tissues. This differential absorption creates a greater contrast between the different tissues being imaged, which helps to delineate structures that may otherwise appear similar with higher kVp settings.

A higher kVp, on the other hand, increases the penetration of x-rays, leading to a more uniform exposure of the film or detector and potentially resulting in lower contrast. Increasing mAs (milliamperes-seconds) affects the overall density of the image but does not have a direct impact on the contrast itself, as it influences the amount of radiation rather than the energy level. Decreasing exposure time relates more to motion blur than to contrast, as it primarily affects the duration of exposure rather than the quality of the image concerning tissue differentiation.