MyHealth@Eu NCPeH API - Local Development build (v0.0.1) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

Imaging Retrieval

This page describes the implementation options of the Images Retrieval task.

Business View

The overall business scenarios associated to this task is described in the Business view page

Application View

The implementation-indipendent sequence diagrams associated to this task is described in the in the Application view page

Implementation pre-requisites

The Myhealth@EU general architecture requires that no assumptions are made on the way the service is implemented at the national level.

Implementation alternatives

Different alternatives have been considered for the retrieval and display of images:

1. the retrieval of images through the NCPeH by using the DICOM Retrieve WADO-RS service in accordance with the IHE Web-based Image Access (WIA) WADO-RS Retrieve RAD-107 transaction.
2. the remote launch of a DICOM viewer on based on speciifed search parameters. See the IHE profile Invoke Image Display IID

This version will rely on the images retrieval through the DICOM Retrieve WADO-RS service.

Implementation

Using the DICOM WADO-RS, three different REST APIs are supported:

Endpoint	Description
/studies/{studyUID}	Retrieve metadata or details for a study
/studies/{studyUID}/series/{seriesUID}	Retrieve metadata or details for a series
/studies/{studyUID}/series/{seriesUID}/instances/{instanceUID}	Retrieve a specific instance (SOP)

While other options foreseen by the IHE RAD-107 are not requested for the time being

Endpoint	Description
/studies/{studyUID}/series/{seriesUID}/instances/{instanceUID}/metadata	Get metadata for a specific instance
/studies/{studyUID}/series/{seriesUID}/instances/{instanceUID}/frames/{frameNumber}	Retrieve a specific frame from an image
/studies/{studyUID}/series/{seriesUID}/instances/{instanceUID}/bulkdata/{bulkDataID}	Access bulk data from an instance

To retrieve a study/series/instance, the dicom file is retrieved as a ByteArray using a streaming API.

Herefter, a DICOM Conformance Statement for the MyHealth@EU DICOM Web Access to DICOM Objects over RESTful services (WADO-RS). It provides an overview of the DICOM capabilities supported by the service, specifically focusing on the retrieval of DICOM instances at the Study, Series, and Instance levels.

Overview of DICOM WADO-RS

The DICOM Web Access to DICOM Persistent Objects by RESTful Services (WADO-RS) is a web service that allows for the retrieval of DICOM objects using standard HTTP protocols. The MyHealth@EU WADO-RS service conforms to the DICOM standard for web-based access to DICOM instances.

Conformance to DICOM Standards

DICOM Standard Compliance

The MyHealth@EU WADO-RS service is compliant with the following DICOM standards:

• DICOM PS 3.18 (Web Services): The service adheres to the RESTful web services specifications outlined in DICOM PS 3.18 for the retrieval of DICOM objects.

Supported DICOM SOP Classes

The service supports retrieval for the following DICOM SOP Classes:

SOP Class	SOP Class UID
CT Image Storage	1.2.840.10008.5.1.4.1.1.2
MR Image Storage	1.2.840.10008.5.1.4.1.1.4
Ultrasound Image Storage	1.2.840.10008.5.1.4.1.1.6.1
Secondary Capture Image Storage	1.2.840.10008.5.1.4.1.1.7
Digital Mammography X-Ray Image Storage - For Presentation	1.2.840.10008.5.1.4.1.1.1.2
Positron Emission Tomography (PET) Image Storage	1.2.840.10008.5.1.4.1.1.128
Enhanced MR Image Storage	1.2.840.10008.5.1.4.1.1.4.1
Other relevant SOP Classes as applicable to your service	[SOP Class UID]

Supported DICOM Operations

The service supports the following DICOM WADO-RS operations:

• Retrieve Study: Allows retrieval of all DICOM instances within a specified study.
• Retrieve Series: Allows retrieval of all DICOM instances within a specified series.
• Retrieve Instance: Allows retrieval of a specific DICOM instance.

Supported Transfer Syntaxes

The service supports the following DICOM Transfer Syntaxes for the retrieval of DICOM objects:

Transfer Syntax	Transfer Syntax UID
Implicit VR Little Endian	1.2.840.10008.1.2
Explicit VR Little Endian	1.2.840.10008.1.2.1
Explicit VR Big Endian	1.2.840.10008.1.2.2
JPEG Baseline (Process 1)	1.2.840.10008.1.2.4.50
JPEG Lossless, Non-Hierarchical (Process 14)	1.2.840.10008.1.2.4.70
JPEG 2000 Image Compression (Lossless Only)	1.2.840.10008.1.2.4.90
JPEG 2000 Image Compression	1.2.840.10008.1.2.4.91
RLE Lossless	1.2.840.10008.1.2.5

WADO-RS Service Details

Service Endpoints

The MyHealth@EU WADO-RS service provides the following endpoints for DICOM object retrieval:

• Study Level Retrieval: GET /studies/{studyInstanceUID}
• Series Level Retrieval: GET /studies/{studyInstanceUID}/series/{seriesInstanceUID}
• Instance Level Retrieval: GET /studies/{studyInstanceUID}/series/{seriesInstanceUID}/instances/{sopInstanceUID}

Supported Media Types

The service supports the following media types for DICOM instance retrieval:

• application/dicom: Returns the DICOM object in its native format.
• image/jpeg: Returns the DICOM object as a JPEG image (where applicable).
• application/octet-stream: Returns the DICOM object as a binary stream.

Authentication and Authorization

The WADO-RS service requires copmpliance with the MyHealth@EU security secificaitons for secure access to DICOM instances. Users must be authenticated and authorized to retrieve DICOM objects.

Compliance Notes

• The service is designed to be compliant with GDPR and other relevant European regulations for the secure handling of medical data.
• The service adheres to the DICOM standard for the encoding and transfer of DICOM objects over web services.

Limitations and Assumptions

• The service currently supports retrieval of images and associated metadata. Advanced retrieval options such as retrieving specific frames or applying presentation states are not supported in this version.
• The service assumes that the client application is capable of interpreting DICOM data and displaying it appropriately.