The window level (WL), often also referred to as window center, is the midpoint of the range of the CT numbers displayed. When the window level is decreased the CT image will be brighter and vice versa.

What does the window level control?

In medical imaging the brightness/contrast control is called the “window/level” control, and there is a reasonably standard set of mouse motions for changing the window and level. … This diagram shows how the terms “window” and “level” are related to brightness and contrast adjustment.

What is window width in radiography?

The window width (WW) as the name suggests is the measure of the range of CT numbers that an image contains. A wider window width (2000 HU), therefore, will display a wider range of CT numbers.