Hounsfield unit (for attenuation values)
E387405
The Hounsfield unit is a quantitative scale used in CT imaging to express tissue radiodensity relative to water and air, enabling standardized comparison of attenuation values across scans.
All labels observed (3)
| Label | Occurrences |
|---|---|
| Hounsfield scale | 2 |
| Hounsfield unit | 1 |
| Hounsfield unit (for attenuation values) canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T3777672 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Hounsfield unit (for attenuation values) Context triple: [CT scanner, hasMeasurementUnit, Hounsfield unit (for attenuation values)]
-
A.
DICOM Unique Identifier (UID)
DICOM Unique Identifier (UID) is a globally unique numeric string used in medical imaging to unambiguously identify objects such as studies, series, images, and other DICOM entities.
-
B.
IHE Laboratory
IHE Laboratory is a domain within the Integrating the Healthcare Enterprise initiative that defines standards-based profiles to improve interoperability and information exchange in clinical laboratory workflows.
-
C.
Gundersen method
The Gundersen method is a timing-based system in Nordic combined that converts ski jumping results into staggered start times for the cross-country race so that the first athlete to finish wins overall.
-
D.
provide imaging-based diagnosis for patients of University Medical Center Göttingen
The Department of Radiology at University Medical Center Göttingen is a clinical and academic unit specializing in advanced medical imaging to support diagnosis, treatment planning, and patient care across the hospital.
-
E.
IHE
IHE is a global healthcare initiative that promotes the coordinated use of established standards to improve the interoperability of health information systems.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Hounsfield unit (for attenuation values) Target entity description: The Hounsfield unit is a quantitative scale used in CT imaging to express tissue radiodensity relative to water and air, enabling standardized comparison of attenuation values across scans.
-
A.
DICOM Unique Identifier (UID)
DICOM Unique Identifier (UID) is a globally unique numeric string used in medical imaging to unambiguously identify objects such as studies, series, images, and other DICOM entities.
-
B.
IHE Laboratory
IHE Laboratory is a domain within the Integrating the Healthcare Enterprise initiative that defines standards-based profiles to improve interoperability and information exchange in clinical laboratory workflows.
-
C.
Gundersen method
The Gundersen method is a timing-based system in Nordic combined that converts ski jumping results into staggered start times for the cross-country race so that the first athlete to finish wins overall.
-
D.
provide imaging-based diagnosis for patients of University Medical Center Göttingen
The Department of Radiology at University Medical Center Göttingen is a clinical and academic unit specializing in advanced medical imaging to support diagnosis, treatment planning, and patient care across the hospital.
-
E.
IHE
IHE is a global healthcare initiative that promotes the coordinated use of established standards to improve the interoperability of health information systems.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
computed tomography concept
ⓘ
measurement unit ⓘ radiodensity scale ⓘ |
| abbreviation | HU ⓘ |
| affectedBy |
beam hardening
ⓘ
contrast agent concentration ⓘ kVp (tube potential) ⓘ reconstruction kernel ⓘ |
| appliesTo |
CT voxel values
ⓘ
X-ray attenuation ⓘ |
| definedRelativeTo |
air
ⓘ
water ⓘ |
| enables |
comparison of CT scans across scanners
ⓘ
quantitative CT analysis ⓘ tissue characterization in CT ⓘ |
| hasAlternativeName |
Hounsfield unit (for attenuation values)
ⓘ
surface form:
Hounsfield scale
|
| hasDimension | dimensionless quantity ⓘ |
| introducedInField | medical imaging ⓘ |
| mathematicalDefinition | HU = 1000 × (μ_tissue − μ_water) / μ_water ⓘ |
| namedAfter | Godfrey Hounsfield ⓘ |
| parameter | linear attenuation coefficient μ ⓘ |
| referenceValue |
air = -1000 HU
ⓘ
water = 0 HU ⓘ |
| relatedTo |
CT number
ⓘ
attenuation coefficient ⓘ quantitative CT ⓘ radiodensity ⓘ |
| scaleType | linear scale ⓘ |
| standardizedBy | scanner calibration to water and air ⓘ |
| typicalValue |
blood ≈ +30 to +70 HU
ⓘ
compact bone ≈ +1000 HU ⓘ cortical bone up to +2000 HU ⓘ fat ≈ -100 to -150 HU ⓘ lung parenchyma ≈ -700 to -900 HU ⓘ soft tissue ≈ +20 to +80 HU ⓘ |
| usedBy |
medical physicists
ⓘ
radiologic technologists ⓘ radiologists ⓘ |
| usedFor |
expressing attenuation values
ⓘ
quantifying tissue radiodensity ⓘ standardized comparison of CT attenuation ⓘ |
| usedIn |
CT imaging
ⓘ
CT perfusion ⓘ bone mineral density assessment by CT ⓘ computed tomography ⓘ liver fat quantification ⓘ lung densitometry ⓘ |
| zeroPoint | water radiodensity ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Hounsfield unit (for attenuation values) Description of subject: The Hounsfield unit is a quantitative scale used in CT imaging to express tissue radiodensity relative to water and air, enabling standardized comparison of attenuation values across scans.
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
CT scanner
this entity surface form:
Hounsfield scale
this entity surface form:
Hounsfield unit
Hounsfield unit (for attenuation values)
→
hasAlternativeName
→
Hounsfield unit (for attenuation values)
ⓘ
subject surface form:
Hounsfield unit
this entity surface form:
Hounsfield scale