What color does fluid density appear as on a CT image?

Fluid density on a CT image appears as light gray. This is due to the way different substances attenuate X-rays during the imaging process. Fluid, such as water or other liquids, has a density that falls between those of air (which appears black) and bone (which appears white). As a result, fluids show up with a lighter shade than surrounding structures that have a higher or lower attenuation.

This understanding is crucial for interpreting CT scans, as it helps identify various structures and conditions in the body. For instance, recognizing the light gray appearance of fluid can aid in diagnosing conditions such as pleural effusion or cysts, where the presence of fluid plays a critical role in medical assessments.