Problem: How do CT scans work? It measures how much blood flows to different regions of the brain to pinpoint brain activity. It uses a series of computer-generated images taken from a single angle to make a composite representation of a slice of the brain's structure. It uses a series of X-ray images taken from different angles and combined by computer into a composite representation of a slice of the brain's structure. It measures the speed at which neurons fire under various circumstances. Looking for Online Tutoring?