Hounsfield Units (HU) are also known as CT numbers.

Hounsfield Units (HU) are also known as CT numbers.

• A. CT Numbers
• B. Attenuation Coefficients
• C. Voxel Values
• D. Pixel Brightness Indexes

Answer: (A)

In CT imaging, the density of each voxel is converted into a standardized density scale you can read off the image. This scale is expressed as Hounsfield units, which are also called CT numbers. The idea is to compare how much X-ray attenuation a tissue causes relative to water (set at 0 HU) and air (set at around -1000 HU). So a voxel with attenuation similar to water is about 0 HU, air is around -1000 HU, and dense bone can be well over +1000 HU. This normalization makes it easy to differentiate tissues across scanners and patients. So the term for Hounsfield units is CT numbers, because they describe the radiodensity on the CT scale. The other phrases refer to underlying physical properties (attenuation coefficients) or are too vague (voxel values, pixel brightness indexes) to capture the standardized radiodensity measurement used in CT.

In CT imaging, the density of each voxel is converted into a standardized density scale you can read off the image. This scale is expressed as Hounsfield units, which are also called CT numbers. The idea is to compare how much X-ray attenuation a tissue causes relative to water (set at 0 HU) and air (set at around -1000 HU). So a voxel with attenuation similar to water is about 0 HU, air is around -1000 HU, and dense bone can be well over +1000 HU. This normalization makes it easy to differentiate tissues across scanners and patients.

So the term for Hounsfield units is CT numbers, because they describe the radiodensity on the CT scale. The other phrases refer to underlying physical properties (attenuation coefficients) or are too vague (voxel values, pixel brightness indexes) to capture the standardized radiodensity measurement used in CT.