DICOM SR to FHIR Resource Mapping IG, published by HL7 Imaging Integration Working Group. This is not an authorized publication; it is the continuous build for version 0.1.0). This version is based on the current content of https://github.com/HL7/dicom-sr/ and changes regularly. See the Directory of published versions

Architecture

This chapter describes the architecture of this implementation guide.

Profiles & Extensions

Resource Profiles

Observation

The mapping of the core DICOM SR measurement groups, measurements and qualitative analysis content items are covered by the following resource profiles:

• Imaging Measurement Group profiles the Observation resource representing DICOM SR measurement group templates:
  • DTID 1410 “Planar ROI Measurements and Qualitative Evaluations”
  • DTID 1411 “Volumetric ROI Measurements and Qualitative Evaluations”
  • DTID 1501 “Measurement and Qualitative Evaluation Group”
• Imaging Measurement profiles the Observation resource representing imaging measurements extracted from DICOM SR measurement templates:
  • DTID 300 “Measurement”
  • DTID 1419 “ROI Measurements”

• Derived Imaging Measurement profiles the Observation resource representing the DICOM SR derived measurement template DTID 1420 “Measurements Derived From Multiple ROI Measurements”

• ​Imaging Qualitative Evaluation profiles the Observation resource representing qualitative evaluation content items

The above resource profiles depend on the following resource profiles:

ImagingSelection

• Image Region – 2D profiles the ImagingSelection resource representing a referenced 2D image region content item CID 111030 “Image Region”
• Image Region – 3D profiles the ImagingSelection resource representing a referenced 3D image region content item CID 111030 “Image Region”
• Referenced Segment profiles the ImagingSelection resource representing a referenced segment content item CID 121191 “Referenced Segment”
• Referenced Segmentation Frame profiles the ImagingSelection resource representing a referenced segmentation frame content item CID 121214 “Referenced Segmentation Frame”
• Source Image For Segmentation profiles the ImagingSelection resource representing a referenced segmentation source image content item CID 121233 “Source Image For Segmentation”
• Source Series For Segmentation profiles the ImagingSelection resource representing a referenced segmentation source series content item CID 121232 “Source Series For Segmentation”
• Region In Space profiles the ImagingSelection resource representing a referenced RT Structure Set content item CID 130488 “Region in Space”
• Volume Surface profiles the ImagingSelection resource representing a referenced volume surface content item CID 121231 “Volume Surface”
• Real World Value Map profiles the ImagingSelection resource representing a referenced real world value map content item CID 126100 “Real World Value Map used for measurement”
• Illustration of ROI profiles the ImagingSelection resource representing a referenced ROI illustration content item CID 121200 “Illustration of ROI”
• Visual explanation profiles the ImagingSelection resource representing a referenced visual explanation content item CID 130401 “Visual explanation

Device

• ​Algorithm Identification profiles the Device resource representing the DICOM SR template DTID 4019 “Algorithm Identification”
• ​Device Participant profiles the Device resource representing the DICOM Document IE device participant DICOM PS3.3 C.17.2.4 Identified Person or Device Macro
• ​General Equipment profiles the Device resource representing the DICOM General Equipment Module DICOM PS3.3 C.7.5.1 General Equipment Module

BodyStructure

• ​Finding Site profiles the BodyStructure resource representing a finding site content item CID SCT#363698007 “Finding Site”

Supporting DataType Profiles

There is no special supporting DataType profiles defined by this IG.

Supporting Extensions

There is no special supporting extensions defined by this IG.

Profile Relationships

DICOM SR Basics

The content of a DICOM SR is a tree of “content items”. Each content item has:

• a coded “Concept Name” describing the content item
• a “Value Type”
• a value (for most value types)
• zero or more children, each of which is also a content item¹

The content item value types relevant to this implementation guide are:

• CONTAINER: a container with children but no value
• NUM: a numerical value with units
• TEXT: a textual value
• CODE: a coded value
  • Note that a CODE content item has a coded concept name and a coded value

Relationship to DICOM SR TID 1500 Measurement Report

This implementation guide maps content items contained within the DICOM TID 1500 Measurement Report to FHIR resources.

All mapped content items are children of the following CONTAINER content items:

Container Concept Name	Child FHIR Resource Profile	Notes
DCM#126010 “Imaging Measurements”	Imaging Measurement Group	See Imaging Measurement Group relationship
DCM#126011 “Derived Imaging Measurements”	​Derived Imaging Measurements	See Derived Imaging Measurements relationship
UMLS#C0034375 “Qualitative Evaluations”	​Imaging Qualitative Evaluation	See Imaging Qualitative Evaluations relationship

e.g. the children of the CONTAINER with a Concept Name of DCM#126010 “Imaging Measurements” are mapped to Measurement Group Observations.

Imaging Measurement Group Relationship

An Imaging Measurement Group CONTAINER contains 0-n NUM content items representing numerical measurements. Each of these is mapped to an Imaging Measurement Observation.

​An Imaging Measurement Group CONTAINER contains 0-n TEXT or CODE content items representing qualitative evaluations. Each of these is mapped to an Imaging Qualitative Evaluation Observation.

The Imaging Measurement Group CONTAINER is mapped to a Imaging Measurement Group Observation.

​The Imaging Measurement Group Observation hasMember element references the child Imaging Measurement and Imaging Qualitative Evaluation Observations.

Note: Not all TEXT or CODE content items contained within the Imaging Measurement Group represent qualitative evaluations.

A TEXT or CODE child content item should only be interpreted as a qualitative evaluation if it does not have a Concept Name from the following list:

• DCM#112039 “Tracking Identifier”
• DCM#121071 “Finding”
• DCM#130400 “Geometric purpose of region”
• NCIt#C67447 “Activity Session”
• SCT#276214006 “Finding Category”
• SCT#363698007 “Finding Site”
• SCT#370129005 “Measurement Method”

Derived Imaging Measurements Relationship

​A Derived Imaging Measurement CONTAINER contains 0-n NUM content items representing derived numerical measurements. Each of these is mapped to a Derived Measurement Observation.

A Derived Imaging Measurement CONTAINER contains 0-n Imaging Measurement Group CONTAINER content items. Each of these is mapped to an Imaging Measurement Group Observation (see Imaging Measurement Group relationship).

​The Derived Imaging Measurements Observation derivedFrom element references the child Imaging Measurement Group Observations.

Imaging Qualitative Evaluations Relationship

​An Imaging Qualitative Evaluations CONTAINER contains 0-n TEXT or CODE content items representing qualitative evaluations. Each of these is mapped to an Imaging Qualitative Evaluation Observation.

Device Relationship

A FHIR Observation can only have a single device value. However, a DICOM SR can have a device defined at multiple levels:

• A Manufacturer and Model Name defined in the Equipment IE
• A device participant defined in the Document IE
• An algorithm defined in:
  • The Imaging Measurements Container
  • The Derived Imaging Measurements Container
  • The Qualitative Evaluations Container
  • An Imaging Measurement Group
  • An Imaging Measurement
  • ​An Imaging Qualitative Evaluation

​The DICOM SR General Equipment attributes are mapped to a General Equipment Device.

​If the DICOM SR Participant Sequence (0040,A07A) contains an item where Observer Type (0040,A084) has a value of “DEV”, this item is mapped to a Device Participant Device.

​If an Imaging Measurement Group, Imaging Measurement or Imaging Qualitative Evaluation has a child with Concept Name DCM#111001 “Algorithm Name” then it is mapped to an Algorithm Identification Device.

If a DICOM SR document contains multiple devices each is mapped to a Device resource. All devices below the Equipment IE level will populate the parent element to indicate the Device relationships.

​If an Imaging Measurement Group, Imaging Measurement or Imaging Qualitative Evaluation does not have a defined device then the device element references that of its parent.

e.g.

• If an Imaging Qualitative Evaluation is part of an Imaging Measurement Group:
  • If both have a defined Algorithm Identification Device, the Imaging Measurement Group Device will be the parent of the Imaging Qualitative Evaluation Device.
  • If the Imaging Measurement Group does not have a defined Algorithm Identification Device the Imaging Qualitative Evaluation device parent is either the Device Participant Device or the General Equipment Device.
  • If the Imaging Qualitative Evaluation does not have a defined Algorithm Identification Device it’s device element will reference the device of its parent

Other Resource Relationships

All DICOM SOP Instances include information relating to the patient, service request, procedure, etc.

This implementation guide assumes that these resources already exist in the destination FHIR server and does not include a full mapping between their DICOM representation and their FHIR representation.

Instead, it specifies the identifier mapping to allow newly-created resources to be associated with the appropriate existing FHIR resources.

​See DICOM SR Information Object Definition (IOD) Mapping to FHIR and DICOM SR Document Information Entity (IE) Mapping to FHIR.