A.7.2 Updated Pattern based on A_DicomCompositeObjectReference minimal (COCT_RM830120UV)

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The A_DicomCompositeObjectReference minimal pattern has been updated for harmonization with the HL7 V3 assertion pattern. It is used to reference DICOM composite objects within HL7 Version 3 messages in the context of acts and observations. It provides detailed information on the referenced DICOM composite object such as images, presentation states and DICOM structured documents. Mappings from DICOM object attributes to the various Act attributes are provided. The CMETs for the HL7 V3 message DICOM composite object references and the corresponding CDA Release 2 section entries are structurally identical. For the CDA section entries different clone names are used according to the specified entry names in the CDA Release2.

Note: The A_DicomCompositeObjectReference minimal CMET COCT_RM830120 may be used in combination with COCT_RM830110 which provides a single location for lookup of referenced DICOM composite objects of an HL7 V3 message (identifying information on the DICOM study/series/instance hierarchy can be found there).

The following description of the act classes and act relationships contains the attribute mappings of HL7 V3 attributes to DICOM (Digital Imaging and Communications in Medicine) tags. The group and element number of the mapped DICOM tags are listed in parenthesis. The CDA mappings specify the use of the CMET act classes and act relationships as CDA Release 2 document section entries.

1 SopInstance

The SopInstance act class contains the DICOM Service Object Pair (SOP) Instance information for referenced DICOM composite objects. The SopInstance act class is used to reference both, image and non-image DICOM instances. The text attribute contains the DICOM WADO (Web Access to Persistent DICOM Objects, DICOM Standard PS 3.18) reference.

Table 1

DICOM COMPOSITE OBJECT REFERENCE IN AN HL7 V3 ACT

Attribute Data Type Multiplicity Value
classCode CS 1..1 DGIMG
moodCode CS 1..1 EVN
templateId LIST<II> 1..*
id II 1..1 <SOP Instance UID (0008,0018) as root property with no extension property> Uniquely identifies the SOP Instance.
code CE 1..1 <SOP Class UID (0008,0016) as code property, 1.2.840.10008.2.6.1 as codeSystem property, DCMUID as codeSystemName property, SOP Class UID Name (from PS 3.6) as displayName property>: Unique Identifier for the SOP Class as Code Property
title ST 0..1 SOP Class UID derived name
text ED 0..1 <”application/DICOM” as mediaType property, WADO reference (see Table X.3-6) as reference property>
effectiveTime TS 0..1 <Content Date (0008,0023): The date the content creation (e.g. image pixel data, document) started; and Content Time (0008,0033 ): The time the content creation (e.g. image pixel data, document) started.>

The DGIMG classCode is used to reference all DICOM Composite Instances, not just diagnostic images.

WADO is a service that enables the Web Client System to retrieve DICOM Persistent Objects managed by a Web Enabled DICOM Server, through the HTTP/HTTPs protocol. The WADO reference uses an URI with query parameters (Table 7). Access to the content of a data object is enabled by specifying a "link" pointing to a specific DICOM Persistent Object by means of its URL/URI and specifying its DICOM object Instance UID and the transfer syntax to be employed.

Table 2

WADO REFERENCE IN HL7 DGIMG OBSERVATION.TEXT

WADO Component Source
<scheme>://<authority>/<path> Configuration setting, used by the conversion process, identifying the WADO server
?requestType=WADO Fixed
&studyUID=<uid> Study Instance UID for referenced instance
&seriesUID=<uid> Series Instance UID for referenced instance
&objectUID=<uid> SOP Instance UID for referenced instance
&contentType=application/DICOM Fixed

1.1 CDA Mapping (Class Name and Attributes used for CDA Documents)

— Act clone name of the CDA entry is “Observation” instead of “SopInstance”. The attributes and attribute values of this CDA entry “Observation” are identical to those listed in table 1 and 2, except for the optional title attribute (Value: SOP Class UID derived name) which is not mapped because it is not supported by CDA Act Entries.

— templateId value (Table 1): Set root portion of II to “2.16.840.1.113883.10.20.6.2.8” (identifies the template that defines constraints on “SopInstance Observation” of CDA Diagnostic Imaging Reports as specified by CDA R2 DIR IG).

2 ActRelationship SUBJECT (SopInstance recursive actRelationship)

This optional recursive “SUBJECT” actRelationship is used to link a referenced DICOM Presentation State to one or more associated referenced DICOM images (SopInstance act class is used in both cases) it is applied to.

2.1 CDA Mapping (ActRelationship Name and Attributes used for CDA Documents)

— ActRelationship Clone name: entryRelationship (replaces SUBJECT)

— ActRelationship.typeCode: x_ActRelationshipEntry (Constraint: Fixed value = SUBJ)

— ActRelationship.contextControlCode: “AP” (Additive Propagating)

— ContextConductionInd: “true”

3 ActRelationship REASON (SopInstance to PurposeOfReference)

This optional “REASON” actRelationship is used to relate a referenced DICOM composite object (SopInstance ActClass) with the PurposeOfReference ActClass which includes the coded purpose(s) of reference.

3.1 CDA Mapping (ActRelationship Name and Attributes used for CDA Documents)

— ActRelationship Clone name: entryRelationship (replaces REASON)

— ActRelationship.typeCode: x_ActRelationshipEntry (Constraint: Fixed value = RSON)

— ActRelationship.contextControlCode: “AP” (Additive Propagating)

— ContextConductionInd: “true”

4 PurposeOfReference

Describes the purpose the DICOM composite object reference is made for. Appropriate codes such as externally defined DICOM codes may be used to specify the semantics of the purpose of reference. When absent, implies that the reason for the reference is unknown.

Codes specified in DICOM Part 16 "Content Mapping Resource" (DICOM PS 3.16) shall be used to designate the coded purpose of reference by using the value attribute. Candidate codes are contained in the DICOM Context Group 7003. The attribute mapping for the code attributes are listed in table 3.

Table 3

DICOM CODED PURPOSE OF REFERENCE IN AN HL7 V3 ACT

Attribute Data Type Multiplicity Value
classCode CS 1..1 OBS
moodCode CS 1..1 EVN
templateId LIST<II> 1..*
code CD 1..1 <”ASSERTION” as code property, 2.16.840.1.113883.5.4 as codeSystem property> (HL7 observation type code specified for assertions)
value CD 1..1 <Code Value (0008,0100) as code property, 1.2.840.10008.2.16.4 as codeSystem property, Coding Scheme Designator (0008,0102) as codeSystemName property, Code Meaning (0008,0104) as displayName property>

4.1 CDA Mapping (Class Name and Attributes used for CDA Documents)

— Act Clone Name: Observation

— Act clone name of the CDA entry is “Observation” instead of “PurposeOfReference”

— The attributes and attribute values of this “Observation” CDA entry are identical to those listed in table 3

— templateId value (Table 3): Set root portion of II to “2.16.840.1.113883.10.20.6.2.9” (identifies the template that defines constraints on “Purpose of Reference Observation” of CDA Diagnostic Imaging Reports as specified by CDA R2 DIR IG).

5 ActRelationship COMPONENT (SopInstance to ReferencedFrames)

This optional “COMPONENT” actRelationship is used to link a referenced DICOM composite object to one or more frames of a DICOM multi-frame image SOP instance.

5.1 CDA Mapping (ActRelationship Name and Attributes used for CDA Documents)

— ActRelationship Clone name: entryRelationship (replaces COMPONENT)

— ActRelationship.typeCode: x_ActRelationshipEntry (Constraint: Fixed value = COMP)

— ActRelationship.contextControlCode: “AP” (Additive Propagating)

— ContextConductionInd: “true”

6 ReferencedFrames

This act class shall be used if the referenced DICOM SOP instance is a multi-frame image and the reference does not apply to all frames. The list of integer values for the referenced frames of a DICOM multi-frame image SOP instance is contained in the Boundary ActClass.

Table 4

DICOM REFERENCED FRAMES IN AN HL7 V3 ACT

Attribute Data Type Multiplicity Value
classCode CS 1..1 ROIBND
moodCode CS 1..1 EVN
templateId LIST<II> 1..*
code CV 1..1 <Code Value (0008,0100): 121190 as code property, 1.2.840.10008.2.16.4 as codeSystem property, DCM as codeSystemName property, Code Meaning (0008,0104): “Referenced Frames” as displayName property>

6.1 CDA Mapping (Class Name and Attributes used for CDA Documents)

— Act Clone Name: Observation

— Act clone name of the CDA entry is “Observation” instead of “ReferencedFrames"

— templateId value (Table 4): Set root portion of II to “2.16.840.1.113883.10.20.6.2.10” (identifies the template that defines constraints on “Referenced Frames Observation” of CDA Diagnostic Imaging Reports as specified by CDA R2 DIR IG).

7 ActRelationship Component (ReferencedFrames to Boundary)

This “COMPONENT” actRelationship is used to link the ReferencedFrames ActClass to the Boundary ActClass which contains the list of integer values for the referenced frames of a DICOM multi-frame image SOP instance.

7.1 CDA Mapping (ActRelationship Name and Attributes used for CDA Documents)

— ActRelationship Clone name: entryRelationship (replaces COMPONENT)

— ActRelationship.typeCode: x_ActRelationshipEntry (Contstraint: Fixed value = COMP)

8 Boundary

The act class contains a list of integer values for the referenced frames of a DICOM multi-frame image SOP instance. It identifies the frame numbers within the Referenced SOP Instance to which the reference applies. The first frame shall be denoted as frame number 1. This act class shall be used if the referenced DICOM SOP instance is a multi-frame image and the reference does not apply to all frames.

Table 5

BOUNDARY ACTCLASS

Attribute Data Type Multiplicity Value
classCode CS 1..1 OBS
moodCode CS 1..1 EVN
templateId LIST<II> 1..*
code CE 1..1 < Code Value (0008,0100): 113036 as code property, 1.2.840.10008.2.16.4 as codeSystem property, DCM as codeSystemName property, Code Meaning (0008,0104): ”Group of Frames for Display” as displayName property>
value LIST<INT> 1..* <Referenced Frame Number (0008,1160)> Identifies the frame numbers within the Referenced SOP Instance to which the reference applies. The first frame shall be denoted as frame number 1. Values shall be provided if the Referenced SOP Instance is a multi-frame image and the reference does not apply to all frames.

8.1 CDA Mapping (Class Name and Attributes used for CDA Documents)

— Act Clone Name: ObservationAct clone name of the CDA entry is “Observation” instead of "Boundary".

— templateId value (Table 5): Set root portion of II to “2.16.840.1.113883.10.20.6.2.11” (identifies the template that defines constraints on “Boundary Observation” of CDA Diagnostic Imaging Reports as specified by CDA R2 DIR IG).