Which type of artifact can result from improper patient positioning during an X-ray?

Improper patient positioning during an X-ray can lead to the distortion of the image. This occurs because the anatomical structures may not be aligned correctly with the X-ray beam. When the patient's body is not positioned as required, the expected geometry of the structures being imaged can become altered, leading to an inaccurate representation of their size, shape, and relationship to one another. This can ultimately affect diagnostic accuracy, as it may mislead the interpretation of the X-ray results.

In contrast, the other choices involve different types of imaging artifacts. Motion blur arises when the patient moves during the exposure, affecting the sharpness of the image rather than its geometric accuracy. Increased image contrast relates to the difference between dark and light areas in an image, which is generally influenced by technical factors such as X-ray technique and film processing rather than positioning. A reduction in resolution refers to the level of detail that can be seen in an image, which could occur due to various factors including technical settings or film quality, but is not directly a result of positioning.