Final answer:
A window width of 300 and a window level of 30 on a CT scanner will display dense calcifications in the heart as bright white.
Step-by-step explanation:
The window width and window level settings on a CT scanner determine how the grayscale image is displayed. In this case, a window width of 300 and a window level of 30 means that a range of CT numbers, corresponding to different tissue densities, will be displayed on the grayscale image. Dense calcifications in the heart will likely have high CT numbers and appear bright white on the image.