On CT, cortical bone appears which color?

On CT, cortical bone appears which color?

• A. White
• B. Dark gray
• C. It is not visible on CT
• D. Black

Answer: (A)

On CT, brightness reflects how much X-ray energy a tissue attenuates. Cortical bone has a high mineral content, so it attenuates X-rays strongly and appears as the brightest area—white—on the image. This high attenuation corresponds to high Hounsfield units, roughly around a thousand or more. In contrast, fat and softer tissues appear as mid-gray, while air appears black. So cortical bone is white on CT.

On CT, brightness reflects how much X-ray energy a tissue attenuates. Cortical bone has a high mineral content, so it attenuates X-rays strongly and appears as the brightest area—white—on the image. This high attenuation corresponds to high Hounsfield units, roughly around a thousand or more. In contrast, fat and softer tissues appear as mid-gray, while air appears black. So cortical bone is white on CT.