Hounsfield units
Read Your Scan Editorial Team·Last updated
Written from published radiology references and reviewed for plain language. Not written or signed by a physician, and not a diagnosis. How we write these pages →
In plain language
CT's density scale, where water is zero, air is far below it and bone is far above. It lets a radiologist say what something is made of — a number in the range of fat, fluid or blood is often enough to identify a finding without any further test.
Where you’ll see this
CT findings, as a measurement written "HU" — for example "a 6 HU lesion", meaning simple fluid.
Your report may word it “HU”, “Attenuation” or “Density measurement”. These mean the same thing.
Questions worth asking your doctor
- Did this scan use the right technique to answer my question?
- Would contrast, or a different sequence, show something this one could not?
- Do I need another scan, or is this one enough?
How the scan was taken
Where this word comes up
See this word on your own scan
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