Final answer:
Pixel values below -350 HU will be displayed as black in a CT myelogram with a 2100 window width and a 700 window level.
Step-by-step explanation:
When a CT myelogram specifies a window width of 2100 and a window level of 700, we can calculate which pixel values will be displayed as black on the resulting image. The window width defines the range of Hounsfield units (HU) that can be visualized, from the lowest to the highest values, and the window level sets the center of this range. The range of pixel values that will be displayed can be determined by subtracting and adding half of the window width to the window level. In this case, the range is from -350 HU to 1750 HU (700 - 1050 and 700 + 1050, respectively), and thus any pixel value below -350 HU will be displayed as black.