CAMRT Radiography Practice Exam

In an abdominal scan with a typical window level of +50 and a window width of 350, how would a nodule with a Hounsfield number of +320 appear?

1. All black

2. Grey

3. All white

4. Translucent

The correct answer is: All white

In a typical abdominal scan with a window level of +50 and a window width of 350, the window settings determine how different Hounsfield units (HU) are visualized on the image. The window level sets the midpoint of the grayscale mapping, while the window width determines the range of Hounsfield units that will be displayed in various shades of grey. The window level of +50 means that the Hounsfield unit of +50 is represented as a middle gray. The window width of 350 indicates that the range spans from –100 (Hounsfield numbers considerably lower than the window level) to +250 (Hounsfield numbers considerably higher), giving a wide range of contrast in the image. A nodule with a Hounsfield number of +320 falls above the maximum range of the window width (+250). In this case, anything above the maximum range of the window width will be displayed as white on the imaging output. Therefore, the nodule will appear very bright or white, indicating a high density material such as a calcified or high-contrast structure. This understanding of Hounsfield units, window levels, and widths is essential in radiographic interpretation, as it allows technologists and radiologists to assess and