The center number of a range of CT numbers displayed in an image is known as what?

The center number of a range of CT numbers displayed in an image is referred to as the window level. In computed tomography, window level controls the midpoint of the gray scale that is displayed, effectively determining the brightness of the image. By adjusting the window level, a radiologist can enhance the visibility of different structures within the body, as it sets the central value around which the range of pixel values (or CT numbers) is adjusted.

For instance, if the window level is set to a higher CT number, the image may appear lighter, allowing less dense structures to be visualized more clearly. This adjustment is crucial for differentiating between various tissues and pathological conditions within the scanned area.

This concept is distinct from window width, which refers to the range of CT numbers displayed and influences the contrast of the image, as well as other terms related to image properties that do not specifically denote the center value of the CT number range.