Final answer:
A Computed Tomography (CT) scan is a medical imaging technique that produces detailed three-dimensional cross-sectional images of the brain, which can be enhanced with a contrast medium.
Step-by-step explanation:
The diagnostic test that produces a three-dimensional cross-sectional view of the brain, with or without a contrast medium, is known as a Computed Tomography (CT) scan. This noninvasive imaging technique uses a combination of X-rays and computer technology to generate detailed images. During a CT scan, a patient lies on a motorized platform while an X-ray source rotates around them, capturing multiple images from different angles. These images are then processed by a computer to create a detailed cross-sectional view, or 'slice,' which can reveal minute details about the brain's structure, such as the presence of tumors or atrophy.