What does window width in CT imaging control?

Window width in CT imaging plays a crucial role in controlling image contrast. It defines the range of Hounsfield units (HU) that are displayed in the final image. A wider window width accommodates a larger range of densities, which tends to decrease the contrast between different tissues, making them appear more similar. Conversely, a narrower window width displays a more limited range of densities, enhancing the differences in tissue attenuation, which increases the perceived contrast in the image. This capability is essential for differentiating between various tissues, particularly in cases involving tumors or other pathological conditions where contrast is key to diagnosis.

Brightness, resolution, and clarity do not directly relate to window width. Brightness is typically adjusted through the window level, resolution pertains to the detail of the image which is influenced by the scanner's specifications and reconstruction algorithms, while clarity is more subjective and involves the overall quality of the image but does not stem from window width settings.