Scale of CT radiodensity (water equals 0 HU, air equals minus 1000 HU, bone approximately plus 1000 HU)
Expansion
Hounsfield Unit
Purpose
Quantifies tissue attenuation on CT
Clinical Context
HU scale enables objective tissue characterisation. Ranges: air minus 1000, lung minus 500, fat minus 100, water 0, muscle plus 40, blood plus 40 to 60, bone plus 200 to 400.
Related Terms
- Radiodensity
- Attenuation
- Density measurement
Key Points
- HU values help characterise lesions: fat less than minus 40, cyst 0 to 20, fluid 10 to 20, soft tissue 30 to 40, blood 30 to 60, bone greater than 200