7.4.1.6 Acquisition Context

This normative section contains extensions to DICOM tags defined in the Acquisition Context module.

For orthodontic photography, we make use of the Acquisition Context module to encode the conditions of the patient during the photographic acquisition session (lips and mouth open, closed, smiling, relaxed, etc), the occlusal relationship (centric occlusion, centric relation, see Appendix D: Definitions (Informative)), the Image View (projection) and the Image View Modifier (direct or indirect) during the photographic acquisition session.

<QUESTION FOR TONI: Though it is mentioned above, I don’t see the Image View or Image View Modifier specified in the context details below>

Each of these is encoded as a sequence item in the Acquisition Context Sequence. Table 7.4.1.6-1 and Section 7.4.1.6.1 specifiy how each acquisition context is encoded.

References:

• DICOM PS3.3: C.7.6.14

• Extensions in Table 7.4.1.6-1 are from ADA Standard No. 1114 Rev. ??. Section 6.1

Table 7.4.1.6-1 Acquisition Context Module Attribute Requirements

Attribute	Tag	Type	Attribute Description
Acquisition Context Sequence	(0040,0555)	O+	Zero or more Items shall be included in this Sequence. Each sequence item is encoded using the Content Item Macro that describes one discreet, coded acquisition context value of the photographic acquisition session.
> Value Type	(0040,A040)	R+	Shall be “CODE”, unless the Concept Name Code is (128740, DCM, “Longitudinal Temporal Offset from Event”), in wich case the value shall be “NUMERIC”.
> Concept Name Code Sequence	(0040,A043)	R+	Coded concept name of this name-value Item. Only a single Item shall be included in this Sequence. The coded value is taken from DICOM TID 3465 VL Orthodontic Acquisition Context. Each sequence item is encoded using the DICOM Content Item With Modifiers Macro .
> Concept Code Sequence	(0040,A168)	R+	Coded concept value of this name-value Item. Only a single Item shall be included in this Sequence. See 7.4.1.6.1 Acquisition Context Sequence Items for coded values under each Concept Name Code

7.4.1.6.1 Acquisition Context Sequence Items

Each sequence item describes one or more of the following, using the specifications and codes in the subsections below.

• Orthognathic Functional Conditions - e.g., lips and mouth open, closed, smiling, relaxed, etc)

• Orthodontic Finding by Inspection - artifact on the patient which is identified as part of the inspection during a visit or encounter

• Orthodontic Observable Entity

• Dental Occlusion - centric occlusion, centric relation

• Longitudinal Temporal Event Type

• Longitudinal Temporal Offset from Event

7.4.1.6.1.1 Orthognathic Functional Conditions

Optionality: Recommended. Zero or more functional conditions present during acquisition, such as position of lips, mandible position, mouth position. These include functional conditions that might influence the clinical treatment of jaws and/or alignment of teeth and SHOULD be present, if known.

This section specifies coded values in DICOM CID 4066 that can be used when Concept Name Code in (0040,A043) is (130325, DCM, “Orthognathic Functional Condition”).

Attribute Name	Tag	Value	Meaning
> Acquisition Context Sequence	(0040,0555)
>> Concept Name Code Sequence	(0040,A043)	(130325, DCM, “Orthognathic Functional Condition”)
>> Concept Code Sequence	(0040,A168)	One of CID 4066 Orthognathic Functional Conditions	See 7.2.6 Orthognathic Functional Conditions.

7.4.1.6.1.2 Orthodontic Finding by Inspection

Optionality: Optional Zero or more findings MAY be specified. A finding by inspection is an artifact on the patient which is identified as part of the inspection during a visit or encounter.

This section specifies coded values in DICOM CID 4067 that can be used when Concept Name Code in (0040,A043) is (118243007, SCT, “Finding by inspection”).

Attribute Name	Tag	Value	Meaning
> Acquisition Context Sequence	(0040,0555)
>> Concept Name Code Sequence	(0040,A043)	(118243007, SCT, “Finding by inspection”)
>> Concept Code Sequence	(0040,A168)	One of CID 4067 Finding by inspection	See 7.2.7 Orthodontic Finding by Inspection.

7.4.1.6.1.3 Orthodontic Observable Entity

Optionality: Optional

This section specifies coded values in DICOM CID 4068 that can be used when Concept Name Code in (0040,A043) is (363787002, SCT, “Observable entity”).

Attribute Name	Tag	Value	Meaning
> Acquisition Context Sequence	(0040,0555)
>> Concept Name Code Sequence	(0040,A043)	(363787002, SCT, “Observable entity”)
>> Concept Code Sequence	(0040,A168)	One of CID 4068 Orthodontic Observable Entity	See 7.2.8 Orthodontic Observable Entity.

7.4.1.6.1.4 Dental Occlusion

Optionality: Recommended. SHOULD be present, if known. Defines the dental occlusion. Only one value is allowed.

This section specifies coded values in DICOM CID 4069 that can be used when Concept Name Code in (0040,A043) is (25272006, SCT, “Dental occlusion”).

Attribute Name	Tag	Value	Meaning
> Acquisition Context Sequence	(0040,0555)
>> Concept Name Code Sequence	(0040,A043)	(25272006, SCT, “Dental occlusion”)
>> Concept Code Sequence	One of CID 4069 Orthodontic Observable Entity	See 7.2.9 Dental Occlusion.

7.4.1.6.1.5 Longitudinal Temporal Event Type

Optionality: ???

This section specifies coded values in DICOM CID 208 that can be used when Concept Name Code in (0040,A043) is (128741, DCM, “Longitudinal Temporal Event Type”). Note: This Concept Name for CID 280 entries is defined in TID 1502 Time Point Context

Attribute Name	Tag	Value	Meaning
> Acquisition Context Sequence	(0040,0555)
>> Concept Name Code Sequence	(0040,A043)	(128741, DCM, “Longitudinal Temporal Event Type”)	Longitudinal Temporal Event Type
>> Concept Code Sequence	(0040,A168)	One of CID-280

7.4.1.6.1.6 Longitudinal Temporal Offset from Event

Optionality:

• Recommended. SHOULD be present if 7.4.1.6.1.5 Longitudinal Temporal Event Type is present.

• If present, 7.4.1.6.1.5 Longitudinal Temporal Event Type SHALL be present.

Attribute Name	Tag	Value	Meaning
> Acquisition Context Sequence	(0040,0555)		This sequence is omitted for “Initial” and “Final”, as there are no progresses. Note: This Acquisition Context Sequence (0040,0555) without a Numeric Value Attribute (0040,A30A) SHALL be considered invalid, malformed and disregarded. Interpreting it as a zero is a violation of the DICOM standard.
>> Value Type	(0040,A040)	“NUMERIC”
>> Concept Name Code Sequence	(0040,A043)	(128740, DCM, “Longitudinal Temporal Offset from Event”	This Concept Name comes from DICOM TID 1502 Time Point Context
>> Numeric Value	(0040,A30A)	0,1,2,3,…	Required. Number of days past the Event Type. Zero or a positive integer, in units of days. If value is unknown, the entire sequence should be omitted. If value is zero (0), the integer zero SHALL be used.