Hounsfield units - scale of HU, CT numbers
The Hounsfield scale of tissue density is based on two values: air as -1000HU (minimum HU value) and water as 0HU. Density of other tissues is related to this range, usually from -1000 to +1000HU (-1024 to 1024 or 3072 depending on the coding of particular vendor). However, the scale by its the definition is open-ended.
| Matter | Density (HU) |
|---|---|
| Air | -1000 |
| Lung parenchyma (inspirium) | -850 to -910 |
| Fat | -50 to -100 |
| Water | 0 |
| White matter | 20 to 30HU |
| Kidney | 20 to 40HU |
| Spleen | 35 to 55HU |
| Grey matter | 37 to 45HU |
| Blood | 45 to 65HU |
| Liver | 45 to 65HU |
| Hematoma | 40 to 90HU |
| Bone | 700 to 3000 |
References:
1. Buzug TM. Computed Tomography: From Photon Statistics to Modern Cone-Beam CT. Springer; 2008:475
2. Heymsfield S. Human Body Composition. Human Kinetics; 2005
3. Prokop M. Spiral and Multislice Computed Tomography of the Body. Thieme; 2003.
Updated 15/11/2013 12:55 by Lambert