# Clarification needed

**URL:** <https://forum.loinc.org/t/clarification-needed/3001>\
**Category:** General\
**Created:** [March 11, 2026, 5:26pm UTC](https://forum.loinc.org/t/clarification-needed/3001 "2026-03-11T17:26:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![JC32\_pace\_spms](https://forum.loinc.org/letter_avatar_proxy/v4/letter/j/b38774/32.png) [@JC32\_pace\_spms](https://forum.loinc.org/u/JC32_pace_spms)\
**Post date:** [March 11, 2026, 5:26pm UTC](https://forum.loinc.org/t/clarification-needed/3001/1 "2026-03-11T17:26:29Z")

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Hello everyone,

I would like to ask for some clarification regarding the difference between **CT Upper Extremity** and **XR Tomography Upper Extremity**. Could someone explain how these two imaging techniques differ and in what situations each one is typically used?

Thank you for the clarification.

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**Author:** ![jwsnyder](https://forum.loinc.org/letter_avatar_proxy/v4/letter/j/e36b37/32.png) [@jwsnyder](https://forum.loinc.org/u/jwsnyder)\
**Post date:** [March 11, 2026, 7:43pm UTC](https://forum.loinc.org/t/clarification-needed/3001/2 "2026-03-11T19:43:49Z")

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HI Joana,

Thank you for the interesting question. I leared something new that I did not know, but will request that anyone with a radiology background correct me where I mess up.

XR (X-ray) tomography Upper Extremity is a broader term that would encompass any type of tomography performed using an X-ray. In times past, It appears that this may have been done manually with multiple 2-D images.

CT Upper Extremity would be considered a subtype of the broader XR Tomorgraphy concept because it is performed using computerized computation of the series of the 2-D images to create a 3-D representation.

Some other subtypes might be Cone Beam CT, Dual-Energy Ct, Digital mammography (tomosynthesis), and other hybrid systems like PET/CT or SPECT/CT.

I hope that helps.

John

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**Author:** ![pitk0006](https://forum.loinc.org/letter_avatar_proxy/v4/letter/p/c89c15/32.png) [@pitk0006](https://forum.loinc.org/u/pitk0006)\
**Post date:** [March 11, 2026, 7:45pm UTC](https://forum.loinc.org/t/clarification-needed/3001/3 "2026-03-11T19:45:46Z")

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> [@JC32\_pace\_spms](#):
>
> Welcome!

In addition to what John provided, a cursory search revealed some links that might help too.

[https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/ct-vs-mri-vs-xray#:~:text=What%20injuries%20require%20a%20CT,CT%20scans%20can%20spot:](https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/ct-vs-mri-vs-xray#:~:text=What%20injuries%20require%20a%20CT,CT%20scans%20can%20spot:)

[Comparison of the diagnostic accuracy of X-ray and computed tomography in patients with wrist injury - ScienceDirect](https://www.sciencedirect.com/science/article/abs/pii/S0020138320300620#:%5C~:text=XR%20is%20the%20first%20imaging,with%20these%20types%20of%20fractures) .