What is the purpose of creating a mask image during the digital subtraction process?

Creating a mask image during the digital subtraction process serves the primary purpose of subtracting unwanted background information from the final image. The mask image is a reference image that captures the patient’s anatomy and any stationary structures or background noise. When the mask is subtracted from subsequent images taken during a dynamic process, such as a fluoroscopy study, it allows the visualization of only the moving structures, like blood vessels or organs in motion. This enhances the clarity of the image by eliminating static distractions, enabling radiologists to focus on the pertinent details relevant to the diagnosis.

The other options do not accurately reflect the intent of the mask image in this context. Improving color accuracy, enhancing imaging speed, or increasing overall exposure are not goals related to the subtraction process. Instead, they concern other aspects of imaging that are not central to the digital subtraction technique.