November 2014 Bjoern.Nolte@siemens.com

Here are the summary notes from the latest DICOM Working Group 6 Meeting (WG-06).

WG-06 meets 5 times a year to do technical review and harmonization of the output from the 30 DICOM Working Groups.

Current progress on new DICOM supplements (new chapters to The Standard) is shown below. Also change proposals (bug fixes in The Standard) are shown grouped into voting packages (CPacks).

UPS by Restful Services

Sup 171
Final Text in November 2014

This Supplement defines a set of Representational State Transfer (REST) Services for interfacing with the Unified Procedure Step Services. This could be implemented as a proxy to an existing UPS service or as a web service interacting directly with a Workflow Manager.

A clarification discussion took place on when and from whom associations are opened. There are different approaches for UPS-RS user agent initiation and the DIMSE approach.

The DICOM Web service provides a RESTful interface to the UPS Sop Class and provides a set of action types. After careful consideration it was decided that the action types shall all be supported.

The supplement is agreed to go into final text and become part of the standard text.

View details »

Parametric Maps

Sup 172
Final Text in November 2014

This supplement defines use cases and storage of information related to quantitative parametric maps. In general, the term "parametric map" is loosely used to referred to any derived image whose pixel values have a quantitative meaning (e.g., CT HU versus arbitrary MR signal intensity).

Examples of parametric maps include parameters of pharmacokinetic models, such as Ktrans of the Tofts model used in DCE-MRI regional cerebral blood volume (RCBV) or flow (RCBF) used in perfusion CT normalized values based on body size, such as SUVbw used in PET diffusion parameters such as Apparent Diffusion Coefficient (ADC) used in MR DWI.

The objects described in this supplement are like secondary captures for numbers.

The remarks from the Letter Ballot request have been incorporated in the document: Consistent use of double and float Condition is necessary to make sure sending only one of pixel data, float pixel data or double float pixel data.

A discussion occurred where to add this non-mixing restriction in the text. Should general prohibition or a more specific constraint in the Parametric Map IOD as it is now. A general prohibition was agreed upon. This is more robust for display work stations.

The supplement was voted approved to be integrated in the standard as final text.

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MPR Presentation State

Sup 156 Revisit planned for Januar 2014 Sent out for Letter Ballot vote

This supplement introduces the Planar MPR Volumetric Presentation State object to the standard.

The goal is to be able to present the same or close to the same volume view on imaging data (XA-3D, MR, CT enhanced objects and others) with a general volumetric presentation state object regardless of computing and displaying system and vendor. The supplement is the first of a series of supplements. The first one focuses on MPR.

A discussion occurred regarding if the creator needs to choose between cross curve animation method and multiple related presentation state method. This is similar to the decision for a creator to send information as a set of single frames or as one multi frame image.

Normally one presentation state covers on display window. This would fit with the multiple related presentation state method. The animation method would be more useful in a sequential scroll through in one window.

The working group will remove one of the methods or add normative text to guide when to use which one after internal discussions.

The working group presented the recommendations for animated presentations. The example used was cross curve. The viewing application moves the planar MPR view along a curve in the volume.

A further example was presented: The use of annotations in volume space. During an intervention trajectory planning lines representing a needle is introduced to help for further treatment. Visibility and clipping was discussed.

The supplement is approved to go out for letter ballot.

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XR 3D Informative Annex

Sup 167 Revisit planned for Januar 2015
Sent out for Letter Ballot

This Supplement delivers explanatory information on the usage of DICOM attributes for X-Ray 3D Angiographic Image IOD:

  • Detailed additional information like scenarios, examples and drawings beyond the definitions in PS 3.3;
  • Identify scenarios where the X-Ray 3D Angiographic Image is applied;
  • Indicate restrictions on the applicable scenarios;
  • Encourage the usage of Type 3 attributes under particular scenarios;
  • Assess the applicability for some conditional attributes under particular scenarios;
The open issues and the corresponding clarifications were presented including the following statements:

Temporal Position Index could be used in the case multiple rotations and multiple 3D reconstructions. Cross-references with Waveform objects is not expected.

Non-regular sampling is described in more detail. Color is not included in this supplement. There are other means to transfer this type of information. A longer discussion on the use case in figure X2.5-1 came up. In this supplement different phases within one heart beat cycle is broken up in separate stacks: One for each phase.

In contrast MR und CT images a stack is kept together for all the phases together.

The supplement is approved for letter ballot.

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2nd Generation RT

Sup 147 Revisit planned for Januar 2015
Sent out for public comments

The set of supplements introduces the 2nd generation of radiotherapy objects to reflect the advances in modern radio therapy. Today's workflows in radiation oncology are increasingly dynamic along the whole course of treatment, requiring electronic workflow management and other objects of smaller scope than in the 1st generation objects.

The representation of an RT Prescription, which is only rudimentary available in the 1st generation objects and embedded as an extension of a RT Plan, needs its own IOD.

Other aspects like the important 3D modeling and patient position management, expandability to future treatment technologies, streamlining representation of beam and dose data also call for new approaches.

The 2nd generation objects addresses those needs by various means, e.g.:

  • By traceable representation of targets and organs across various objects from different treatment phases.
  • A clear separation of technique-specific versus general aspects.
  • A systematic 3D representation including use of modern 3D segmentation, mesh, rigid and deformable registrations objects.
  • A systematic use of building blocks of shared content among other concepts.

The supplement for Second Generation Radiotherapy has been split up in six parts:

  • Sup 147 2nd Gen RT Prescription and Segment Annotation
  • Sup 175 2nd Gen RT C-Arm Radiations
  • Sup 176 2nd Gen RT New RT Radiations
  • Sup 177 2nd Gen RT Dose Objects
  • Sup 178 2nd Gen RT RT Course
  • Sup 179 2nd Gen RT RT Explanatory (Part 17)
There are two IODs in supplement 147: RT Physician Intent IOD and RT Prescription and Segment Annotation IOD.

Subsequent parts are built on top of Sup 147 and Sup 175, but are self-contained amongst each other and can be implemented and used without the others.

Supplement 175, in a draft state, introduces the general concepts for RT Radiation Sets and the C-Arm treatment techniques. Subsequent supplements (prepared of envisioned) will introduce further treatment techniques.

The supplement 147 was apporved for public comments.

View details in supplement 147 »

View details in supplement 175»

MPEG-4 Transfer Syntax

Sup 169 Revisit planned for January 2015
Sent out for public comments

The complete name of the new supplement is MPEG-4 AVC/H.264 Transfer Syntax.

This supplement describes two new Transfer Syntaxes to embed MPEG-4 Advanced Video Coding (AVC) / H.264 High Profile / Level 4.2 (HiP@Level4.2) and H.264 Stereo High Profile /Level 4.2 encoded pixel data in DICOM. It does not introduce any new SOP Classes or IODs.

Transfer Syntax MPEG-4 AVC High Profile will perform consistent with the ITU-T H.264 HiP@Level4.2. This will enable the storage of video files with a resolution of 1920x1080 at 50Hz/60Hz.

Transfer Syntax MPEG-4 AVC Stereo High Profile will perform consistent with the ITU-T H.264 Stereo High Profile at Level 4.2. This will enable the storage of video files where higher compression can be achieved due to inter-view prediction. An example of the use would be in binocular operational microscopy.

This proposed supplement includes Addenda to existing Parts of DICOM:

  • - PS 3.5 Addendum: Data Structures and Encoding
  • - PS 3.6 Addendum: Data Dictionary
In the years since the DICOM Committee WG13 approved the new MPEG-4 AVC/H.264 Transfer Syntax with supplement 149, the capabilities of video recorders and video players have advanced considerably.

Support is required in DICOM for 1080P 50/60 Hz as defined by MPEG-4 AVC / H.264 Level 4.2. Considerable space savings can be achieved when storing stereo recordings in Stereo High Profile format.

Basis was an older supplement 149 with copy and paste. Some adjustments have been done.

A discussion occurred if the supplement covers codex for typical real world use cases like mobile devices. (H.265 which is the new standard after H.264). Currently the working group is not addressing this feature.

Voted ready to go out for public comment.

View details »

Substance Admin SR

Sup 164 Revisit planned for Januar 2015
Stays in draft state

The supplement applies to all modalities in which radiographic, radiopharmaceutical or other imaging agents are introduced into a circulatory system in a controlled fashion (CT, MR, XA, NM, US).

Following are the new SOP Classes introduced to describe administration events, flows, pressure, timings, physio-chemical attributes and pharmacological attributes of the agent administration and also consumables related to the administration.

These SOP classes do not describe radioactivity or dosimetry administered.

- The Defined Substance Administration SR is for defining generic substance administration protocols for known generic study protocols.

- The Planned Substance Administration SR Storage SOP Class is intended for representing the plan or program to deliver imaging agent customized to a specific patient.

- The Performed Substance Administration SR is for reporting the actual plan or program that was used to deliver the diagnostic imaging agent during a medical imaging study.

- In addition, the Basic Performed Substance Administration provides a summarized version of the performed substance administration. This is an attribute based class instead of a SR document. The primary use of this class is for communicating administration data to a modality system during an imaging study.

A walk through with corrections and improvements of attributes, conditions and codes was performed.

The supplement stays in a draft state.

View details »

RESTfull Rendering

Sup 174 Revisit planned for Januar 2015

The decision was made that there will be three separate services for restful rendering.

The services are divided into three groups: DICOM Services, Rendered Services, Rendered Presentation State Service.

The services retrieve one of the following: Retrieve DICOM Study, Series and Instances, Retrieve Rendered Study, Series and Instances, Retrieve Presentation State Series or Instance.

Basic Image Review Functionality contains Layout, Tiling, Selection, Rotation by 90 degree, increments, Flip horizontal, Windowing, Zoom, Pan and Laterality Overlay

The closed issues were discussed. The point of adding vendor specific parameters was scrutinized. Both server and client should be allowed too ignore additional parameters introduced by a product implementer.

The supplement stays in a draft state.

View details »

Web Services Re-Doc

Sup 183 Revisit planned for January 2015

Web Services Re-documentation is the name of the supplement which is restructuring part 18 of the DICOM standard.

A first draft of part 18 in DICOM was presented. The main idea is to harmonize with other standards through a restructuring. The use of common vocabulary is an essential goal of this effort.

The structure of the document is:

  • Conformance
  • Normative References
  • Terms and Definitions
  • Symbols and Abbreviations
  • Web Services Overview
  • WADO URI Protocols
The first sections of the document was walked through and the text was discussed and improved.

View details »

CPack 78

WG-06 approved Final Text in November 2014

1350 Add WADO-RS as a retrieval mechanism for referenced Instances 1366 Correction of Relationships in Planar and Volumetric ROI Templates 1367 Correct errors in Colon CAD SR IOD Template Figures 1368 Space should be listed in DS and IS VR character repertoire 1369 Relax device identifier constraint in x-ray irradiation event per CP 1065 undone by CP 1077 1370 Conformance Statement Example is Missing Private Creator Value 1371 Length of TM permitted is too long 1372 Add NCI Thesaurus as Coding Scheme 1373 Add Alzheimers Disease PET Radiotracers 1374 Add Zr 89 Monocolonal Antibody PET Radiotracers 1375 Add Various PET Radionuclides and Radiotracers 1376 Add Individual Long Bone Concepts to Anatomic Region and Body Part Examined 1377 Use SNOMED Code for Radiopharmaceutical 1378 Add Anatomic Codes for Fetal Biometry and Pelvic Ultrasound 1379 Add Definitions for all DCM Controlled Terms or Replace with Terms from External Lexicon 1380 Various NM Radionuclides are not list in CID 18. Add them, using DCM codes if necessary for those not in SNOMED or UMLS. 1381 Add term "Flat Filter" for Filter Types used in Proj. X-Ray 1383 Add external resource URI to MWL 1384 Update values in CID 3722 1385 Add Measurement Laterality to General Ophthalmic Refractive Measurements Module 1386 Addition of Measurement Report Root Template for Planar and Volumetric ROIs 1387 Addition of Quantity Descriptors to Real World Value Maps 1388 Add Real World Value Map Reference to Measurements 1389 Factor Common Descriptions Out of Image Library Entries 1390 Generalize Concepts in Abstract Multi-dimensional Image Model Component Semantics 1391 Addition of Quantity Descriptors for Perfusion and Tracer Kinetic Modelling 1392 Addition of Quantity Descriptors and Measurements for PET 1393 Correct Tag Numbers For BLD Adjusted Positions 1394 Add Radioactive Source Model ID to RT Brachy Application Setups Module 1395 Extend RT Structure Set ROI Color 1396 Clarify Dose Value units for DVH in RT Dose 1397 Multiplicity Structure Classification Code 1398 Add FOR Module to RTSS IOD 1399 Add Effective Wedge Angle 1400 Assign WADO-WS namespace and schema 1401 Clarify meaning of PARTIAL in X-Ray RDSR

CPack 79

WG-06 approved for Letter Ballot (CPack-79) Candidates to go into final text in January 2015

CPack 80 candidates

In the Voting Packet for the April 2015 WG-06 meeting Considered for approval in the next Letter Ballot (CPack-80)
Clicking on one specific Change Proposal above will take to that actual content.

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