CAMRT Radiography Practice Exam

What effect does window level have on CT image appearance?

1. Controls image density

2. Enhances contrast detail

3. Affects image resolution

4. Alters gray scale representation

The correct answer is: Alters gray scale representation

The correct answer is that window level alters gray scale representation. In computed tomography (CT), the window level is essentially the central value of the window width that determines how the various shades of gray are displayed on the image. Adjusting the window level shifts the mid-range of the grayscale, allowing for the enhancement of particular tissues based on their densities, which helps radiologists interpret the images more effectively. While window level does influence aspects such as image density, its primary function is to modify the gray scale to emphasize different anatomical structures. Adjusting the window width would control the range of gray levels displayed, but the window level specifically relates to which part of that range is centered on the gray scale. It's important to note that the other effects mentioned, like contrast detail and image resolution, do not directly relate to the function of window level. Window level primarily alters how shades of gray are represented, aiding in the clear visualization of varying tissue densities.