DICOMweb Modality Services

Content

This repository contains a description on how to do the equivalence of DIMSE MWL & MPPS in a RESTful manner, based on the DICOMWeb Worklist Service (UPS-RS). This equivalence is called DICOMweb Modality Services. In addition there are different examples integrated.

Prerequisites

Tools

In order to extend this repository the following software needs to be installed:

• Studio Code
• Extension PlantUML

Every plantuml diagram can be exported to folder 'diagrams' by using the right mouse click on a plantuml file and selecting Export Workspace Diagrams. However, to do so proper settings on the PlantUML Extension are required (press the cogwheel of the PlanUML extension to edit these):

• select Export Format the entry png
• unselect Export Include Folder Hierarchy (misspelled in the settings as 'Heirarchy' and 'heiracrchy')
• type in Export Out Dir the folder diagrams as main folder containg the diagrams
• unselect Export Sub Folder

Use Cases

The main use case of DICOMweb Modality Services shows the interaction of a Modality with a Worklist Provider, Printer and Image Manager. The scope of this repository is the interaction between several actors with the Worklist Provider.

Another use case in scope is about acquisition modalities in the context of encounter-based imaging, namely when there is no Workitem for the imaging performed. These modalities would need to create a Workitem themselves, in line with the IHE EBIW integration profile.

Furthermore, there are also dashboard-like applications that want to show the progress of the Workitems, or applications that base there behavior on work being done by some other device or application. Both of these require notifications on the status of Workitems.

Mapping the DIMSE MWL & MPPS commands to DICOMWeb Worklist Service Transactions and Requests

MWL & MPPS	Worklist Service Transaction	Worklist Service Request
C-FINDMWL	Search [ & Retrieve Workitem ]	GET {s}/workitems{?query*} [ & GET {s}/workitems/{instance} ]
N-CREATEMPPS	Change Workitem State & Update Workitem	PUT {s}/workitems/{instance}/state & POST {s}/workitems/{instance}{?transaction}
N-SETMPPS	Change Workitem State & Update Workitem & Cancel Workitem	PUT {s}/workitems/{instance}/state & POST {s}/workitems/{instance}{?transaction} & POST {s}/workitems/{instance}/cancelrequest
N-GETMPPS	Retrieve Workitem	GET {s}/workitems/{instance}
N-EVENT-REPORTMPPS	Subscribe Transaction & Delete subscription & Suspend subscription	POST {s}/workitems/{instance}/subscribers/{aetitle} & DELETE {s}/workitems/{instance}/subscribers/{AETitle} & POST {s}/workitems/1.2.840.10008.5.1.4.34.5/

Happy Flow

An overview of the happy flow is given below, where the User Agent is typically an Acquisition Modality, while the Origin Server would be a RIS or the like:

Examples for the single steps using DICOMWeb

• Query Worklist: modality retrieves the worklist items (correlates to DIMSE MWL C-FIND)

Example: Query Worklist

• Retrieve Single Workitem (optional, if not all information was delivered by query transaction)

Retrieve Workitem (optional)

• Start Acquisition the modality claimes the workitem and starts the acquisition

Start Acquisition

• Update Workitem the modality updates the workitem with information for each produced series

Update Workitem

• Complete Acquisition the modality completes the acquisition and completes the study

Complete Acquisition

Definitions

The UPS Push SOP Class allows SCU systems to:

• create (push) a new worklist item (i.e., instance) onto a worklist
• submit a cancellation request for a worklist item

The UPS Pull SOP Class allows SCU systems to:

• query a worklist for matching items
• take responsibility for performing a worklist item
• add/modify progress/status/result details for the worklist item
• finalize a controlled worklist item as Completed or Canceled.

The UPS Watch SOP Class allows SCU systems to:

• query for worklist items of interest
• subscribe/unsubscribe for event notifications of changes to a given worklist item
• subscribe/unsubscribe for event notifications of all worklist items
• get details for a given worklist item
• submit a cancellation request for a given worklist item

The UPS Event SOP Class allows SCU systems to:

• receive event notifications of changes to a worklist item

The UPS Query SOP Class allows SCU systems to:

• query a worklist for matching items.

Useful links

Workflows in hospital

https://hackmd.io/@victoriatjia/fhir-radiology#11-Current-Radiology-Workflow-in-Hospital

DIMSE Modality Worklist

https://dicom.nema.org/medical/dicom/current/output/chtml/part04/sect_k.6.html Matching keys https://dicom.nema.org/medical/dicom/current/output/chtml/part04/sect_K.6.html#table_K.6-1

DIMSE MPPS

https://dicom.nema.org/medical/dicom/current/output/chtml/part04/sect_F.7.2.html#sect_F.7.2.1

DIMSE UPS

https://dicom.nema.org/medical/dicom/current/output/chtml/part04/sect_cc.3.html UPS attributes https://dicom.nema.org/medical/dicom/current/output/html/part04.html#table_CC.2.5-3

DICOMweb UPS

https://dicom.nema.org/medical/dicom/current/output/html/part18.html#chapter_11 https://www.dicomstandard.org/using/dicomweb/workflow-ups-rs

Mapping DICOM MWL to UPS

IHE_RAD_Suppl_EBIW.pdf Table 4.130.4.1.2-1: Return and Matching Keys for Encounter Metadata

DICOM MWL & MPPS examples

https://pydicom.github.io/pynetdicom/dev/examples/qr_find.html

UPS content

https://dicom.nema.org/dicom/current/output/chtml/part03/sect_B.26.html