7.3. SNOMED Codes

This section lists the SNOMED codes used and describes the criteria followed when selecting SNOMED-CT codes. This criteria should be followed when making any kind of modification to this document which affects the selection of SNOMED-CT codes.

SNOMED codes can be very granular and what appears to be the same concept can be represented by different codes. In reality, each code has a different meaning, and one must pay attention when selecting codes in order to maintain consistency within this standard and within the entire DICOM standard.

7.3.1. Use “structure of”

In SNOMED-CT it is frequent to find “Structure of… “ and “Entire…” concepts. Historical convention and institutional knowledge dictate maintaining the consistency with the rest of DICOM and selecting those codes which start with or contain the word “Structure” wherever possible. (From email conversation with David Clunie 2023-04-25).

For example when describing EV-15 in Anatomic Region Modifier Sequence (0008,2220) one might be faced with having to decide between

• 302549007 |Entire face (body structure)

and

• 89545001 |Face structure (body structure)

In this situation, one would choose the latter, “Face structure”.

7.3.2. Prefer post-coordination

In SNOMED-CT, there might be some pre-coordinated codes, such as 784262003 Structure of body of left half of mandible (body structure). When selecting codes for DICOM, it is preferred not to use these. Instead, use one code to define the anatomic region, and another code that “qualifies” that region. In the example above, we would use Mandible as body structrure in the Anatomic Region Sequence, and then modify it with left half in the Anatomic Region Modifier Sequence.

The rationale behind this comes from an email exchange with David Clunie from 2023-02-24:

Also, we (DICOM) don’t normally pre-coordinate laterality, e.g., we wouldn’t use “right half of face”, but instead use its parent, SCT:422624005 “Structure of half of face lateral to midsagittal plane (body structure)”, and post-coordinate laterality. 422624005 half of face is not a modifier, it is the anatomy, so would go in AnatomicRegionSequence, rather than 774007 head and/or neck. AnatomicRegionModifierSequence would contain 24028007 Right.

https://michaelstearns.net/post-coordination-pre-coordination-codified-concepts/ provides a good explanation for the meaning of the term “post-coordination”:

Post-coordination refers to using two codes to represent a clinical expression such as “severe headache.” For example a code exists for the symptom “headache” (e.g., SNOMED CT code 25064002) and a separate code exists for the modifier “severe” (e.g., SNOMED CT code 24484000). These two are then placed together in combination as 24484000 (severe) + 25064002 (headache), allowing the information system to identify when a patient presents with a severe headache vs. just a headache alone or a mild headache.

7.3.3. List of Codes used for ADA/ANSI-1107

• The codeset column contains the abbreviation for the codeset used, i.e. SCT for SNOMED-CT, DCM for DICOM.

• The codes which are not part of a real codeset and are considered CS (Coded String) in DICOM, have CS in the codeset column.

code	codeset	meaning
130324	DCM	Functional condition present during acquisition
ZZZZZZ	DCM	Orthognathic Functional Conditions
262016004	SCT	Open mouth (finding)
1332210001	SCT	Mouth in partially open position
1336028006	SCT	Upper and lower lips in relaxed position
1336029003	SCT	Upper and lower lips in closed position
1336026005	SCT	Mandible postured forward (record artifact)
225583004	SCT	Smiles (finding)
118243007	SCT	Finding By Inspection
276470008	SCT	Skin mark (disorder)
281689009	SCT	Slap mark (disorder)
51089004	SCT	Birthmark (disorder)
341000119102	SCT	Tattoo of skin (finding)
4356008	SCT	Gingival recession (disorder)
710793000	SCT	Cant of occlusal plane (observable entity)
1264188003	SCT	Local exogenous pigmentation of left buccal mucosa
1264193000	SCT	Local exogenous pigmentation of right buccal mucosa
1260043007	SCT	Local exogenous pigmentation of mucosa of soft palate
1260047008	SCT	Local exogenous pigmentation of mucous membrane of lower lip
1260049006	SCT	Local exogenous pigmentation of mucous membrane of upper lip
363787002	SCT	Observable entity
193093009	SCT	Bell’s palsy (disorder)
110343009	SCT	Tongue thrust (observable entity)
25272006	SCT	Dental occlusion, function
110320000	SCT	Centric occlusion (observable entity)
736783005	SCT	Centric relation (observable entity)
255589003	SCT	Direct (qualifier value)
128741	DCM	Longitudinal Temporal Event Type
121079	DCM	Baseline
184047000	SCT	Patient registration (procedure)
C37948	NCIt	Enrollment
122452007	SCT	Comprehensive orthodontic treatment (procedure)
126074	DCM	Posttreatment
128740	DCM	Longitudinal Temporal Offset from Event
d	UCUM	day
24028007	SCT	Right (qualifier value)
7771000	SCT	Left (qualifier value)
123851003	SCT	Mouth region structure (body structure)
774007	SCT	Structure of head and/or neck (body structure)
462735007	SCT	Periodontal probe (physical object)
47162009	SCT	Mirror, device (physical object)
39802000	SCT	Tongue blade, device (physical object)
102304005	SCT	Measuring ruler, device (physical object)
B	CS	Both
L	CS	Left
R	CS	Right
U	CS	Unpaired
P^F	CS	Posterior, Foot
A^F	CS	Anterior, Foot
R^P	CS	Right, Posterior
R^A	CS	Right, Anterior
L^F	CS	Left, Foot
R^F	CS	Right, Foot
L^P	CS	Left, Posterior
L^A	CS	Left, Anterior
88176008	SCT	Lower dental arch structure (body structure)
39481002	SCT	Upper dental arch structure (body structure)
261063000	SCT	Structure of buccal space (body structure)
7652006	SCT	Structure of frenulum labii (body structure)
89545001	SCT	Face structure (body structure)
74262004	SCT	Oral cavity structure (body structure)
399033003	SCT	Frontal projection (qualifier value)
399173006	SCT	Left lateral projection (qualifier value)
260421001	SCT	Left lateral oblique (qualifier value)
399198007	SCT	Right lateral projection (qualifier value)
260424009	SCT	Right lateral oblique (qualifier value)
399182000	SCT	Oblique projection (qualifier value)
260454004	SCT	45 degree projection (qualifier value)
260499007	SCT	Occlusal projection (qualifier value)
399255003	SCT	Submentovertical projection (qualifier value)
260461000	SCT	Vertex projection (qualifier value)
789135000	SCT	Mirrored visible image uncorrected (record artifact)
789134001	SCT	Mirrored visible image uncorrected flipped horizontally
789132002	SCT	Mirrored visible image uncorrected flipped horizontally and vertically
789133007	SCT	Mirrored visible image uncorrected flipped vertically
789131009	SCT	Close up photographic view of teeth with no set magnification or distance
787610003	SCT	Photographic image corrected intraoral mirrored visible record (record artifact)
789310004	SCT	Mirrored photographic image of teeth corrected flipped horizontally
789311000	SCT	Mirrored photographic image of teeth corrected flipped vertically
789312007	SCT	Mirrored photographic image of teeth corrected flipped vertically and horizontally
787612006	SCT	Photographic image extraoral with 45 degree view
787611004	SCT	Photographic image extraoral with mandible postured forward
789313002	SCT	Photographic image of anterior teeth
789314008	SCT	Photographic image of face with lips in relaxed position
787607005	SCT	Photographic image with lips closed
789130005	SCT	Photographic image with mouth partially opened position and teeth apart
51440002	SCT	Right And Left
774007	SCT	Structure of head and/or neck (body structure)
422624005	SCT	Structure of half of face lateral to midsagittal plane (body structure)
70925003	SCT	Bone structure of maxilla (body structure)
91609006	SCT	Bone structure of mandible (body structure)
661005	SCT	Jaw region structure (body structure)
30730003	SCT	Sagittal (qualifier value)
255541007	SCT	Indirect (qualifier value)
261089000	SCT	Inferior (qualifier value)
264217000	SCT	Superior (qualifier value)
278650002	SCT	Edentulous (finding)
		Not Applicable