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type: resourceresource: ImagingSelection

ImagingSelection

Introduction

Scope and Usage

This resource is an event resource from a FHIR workflow perspective - see Workflow.

A selection of data from an ImagingStudy. The selection might be:

Can also represent regions within the ImagingStudy, including:

Uses for ImagingSelection resources include:

All DICOM SOP Instances referenced in a single ImagingSelection resource are part of the same DICOM Series (and therefore also the same DICOM Study). In order to reference SOP Instances in multiple Studies or Series it is necessary to create multiple ImagingSelection resources.

Boundaries and Relationships

The ImagingStudy resource is used to store details of an entire DICOM Study and its relationship to other resources, such as Patient. ServiceRequest and Encounter.

The ImagingSelection resource is used to reference a subset of a study. Instances of this resource are created for specific clinical purposes and are unlikely to change once created.

An Observation typically relates to a set of images in the following ways.

The DocumentReference resource is used to store non-DICOM images, video, or audio with relevant metadata. The DocumentReference resource might be appropriate for including a rendered DICOM image in cases where only the image is needed and not the full image context.

Notes

Notes

Imaging Selection Subsets

Some DICOM SOP Instances contain sub-resources, such as frames, segments, etc.

An Imaging Selection resource can specify the subset of these that are included in the selection using the following elements.

The value of the instance.sopClass element determines which type of subset can be present.

For example:

Note: Because an imaging selection instance is limited to a single DICOM Series and each DICOM Series can contain only one type of instance - image, SR document, radiotherapy object, etc. - each imaging selection instance can only contain one type of subset.

Use of ImagingSelection.code and ImagingSelection.category

The code and category element can be used to provide information relevant for applications that want to identify specific types of ImagingSelection resources.

For example, if an ImagingSelection is used to identify a set of images that make up a volume rendered view, the code could contain a code indicating Volume Rendering - such as RadLex RID35862 - and the category could contain values of the DICOM Image Type (0008,0008) attribute - such as DERVIED and SECONDARY.

{ "resource": { "resourceType": "ImagingSelection", "id": "fa8e0948175f3117a3b8c4be2ff972ec", "subject": { "reference": "Patient/acb045960122378999c97cd7ca532f8b" }, "code": { "coding": [ { "system": "http://radlex.org/", "code": "RID12769", "display": "volume rendering" } ] }, "category": [ { "text": "DERIVED" }, { "text": "SECONDARY" } ] } }

Element Requirements by Selection Type

This section outlines several imaging selection types, each listing a set of resource elements that are required and/or typically present in the selection. Some types require only a minimal set of elements, while others require a comprehensive list to ensure clarity.

Single-Frame Image Selection

An imaging selection that points to one single-frame image requires:

While not required, this type of selection typically includes:

See Single-Frame Image Selection example.

Multiframe Image Selection

An imaging selection that points to frames in a multiframe image requires:

While not required, this type of selection typically includes:

See Multiframe Image Selection example.

2D Image Selection

An imaging selection that points to a 2D region on an image requires:

While not required, this type of selection typically includes:

See 2D Image Region Selection example.

3D Image Selection

An imaging selection that points to a 3D region requires:

This type of selection can also specify a set of images but this is not required. The 3D region selection can be applied to any images that share the same Frame of Reference UID.

See 3D Image Region Selection example.

ImagingSelection Endpoints

The ImagingSelection.endpoint elements indicate network services that can be used to access the imaging data referenced by the imaging selection; for example, a DICOM WADO-RS server. Systems can determine if the relevant imaging data is available or offline by interacting with the endpoint.

Different Endpoint connection types can have different capabilities, protocols or requirements. Furthermore, the specified Endpoint.address identifies the DICOM Web Service Base URI (see DICOM PS 3.18 Section 8.2 ). The URL needed to retrieve image data might need to be constructed from this base URL. See below for the details on use of imaging-related Endpoint connection types.

WADO-RS

An Endpoint.connectionType of code dicom-wado-rs, system http://terminology.hl7.org/CodeSystem/endpoint-connection-type, identifies a DICOM WADO-RS service.

The DICOM WADO-RS (Web Access to DICOM Objects, RESTful mode) service uses a RESTful approach to instance retrieval. This service allows for retrieval of native DICOM SOP instances, or instances “rendered” into other formats, including JPEG and MPEG. The media type of a response is specified by the request Accept header (preferred); or, by the accept query parameters. Supported media types depend on the capabilities of the WADO-RS server and the classification of the instance as "single frame", "multi-frame", "video", "text", or "other". The WADO-RS service also allows retrieval of study or series level information.

The path to retrieve a DICOM instance is constructed by appending the appropriate sub-resource paths to the Endpoint.address value.

For example, using the following information in a fictional ImagingSelection resource:

we can construct the WADO-RS URL to issue an HTTP GET for a native DICOM PS3.10 instance file (if consistent with the Accept header):

https://pacs.hospital.org/wado-rs/studies/1.2.250.1.59.40211.12345678.678910/series/1.2.250.1.59.40211.789001276.14556172.67789/instances/1.2.250.1.59.40211.2678810.87991027.899772.2

WADO-URI

An Endpoint.connectionType of code dicom-wado-uri, system http://terminology.hl7.org/CodeSystem/endpoint-connection-type, identifies a DICOM WADO-URI service.

The DICOM WADO-URI (Web Access to DICOM Objects, URI mode) service uses HTTP query parameter syntax. This service allows for retrieval of native DICOM instances, or instances “rendered” into other formats, including JPEG and MPEG. The media type of a response is specified by the request Accept header (preferred); or, by the contentType query parameter. Supported media types depend on the classification of the instance as "single frame", "multi-frame", "video", "text", or "other."

The query to retrieve a DICOM instance is constructed by appending the appropriate query parameters to the Endpoint.address value.

For example, using the following information in a fictional ImagingSelection resource:

we can construct the WADO-URI URL to issue an HTTP GET for a native DICOM PS3.10 instance file (if consistent with the Accept header):

https://pacs.hospital.org/wado-uri?requestType=WADO&studyUID=1.2.250.1.59.40211.12345678.678910&seriesUID=1.2.250.1.59.40211.789001276.14556172.67789&objectUID=1.2.250.1.59.40211.2678810.87991027.899772.2

Body Site and Laterality

The bodySite element can include the laterality of the (possibly paired) anatomic structures examined – e.g. left knee, bilateral lungs, etc. This can be conveyed in several ways:

StructureDefinition

Elements (Simplified)

Mappings

Resource Packs

list-ImagingSelection-packs.xml

<?xml version="1.0" encoding="UTF-8"?>

<List xmlns="http://hl7.org/fhir">
  <id value="ImagingSelection-packs"/>
  <status value="current"/>
  <mode value="working"/>
</List>

Search Parameters

Full Search Parameters

Examples

Full Examples

Mapping Exceptions

imagingselection-event-mapping-exceptions.xml

Divergent Elements

Unknown does not represent "other" - one of the defined statuses must apply. Unknown is used when the authoring system is not sure what the current status is. | resource=Unknown does not represent "other" - one of the defined statuses must apply. Unknown is used when the authoring system is not sure what the current status is.

Unmapped Elements

imagingselection-fivews-mapping-exceptions.xml

Unmapped Elements