June 2015 Bjoern.Nolte@siemens.com

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

WG-06 meets five 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).

The current edition of the DICOM Standard, incorporating all Final Text supplements and change proposals up to June 2015, is available here:

DICOM Current »

Extensible Structured Report Storage

Sup 186 Final Text in June 2015

This Supplement adds a new extensible IOD and SOP Class that allows new Content Item types to be used as they are added to the standard.

There is an increasing need for new Content Item types (such as SCOORD3D) and these are being added as needed to application-specific IODs and SOP Classes (such as the Colon CAD Supplement 126). There is a need for a generic IOD and SOP Class to allow new applications to make use of these in a general way, yet this conflicts with the requirement to be able to render all content.

A specific conformance requirement is specified, that the user be warned if there is content of a type that the rendering software does not recognize or understand.

In the meeting, a few minor changes from the last version of the document were presented and accepted.

The supplement was approved for final text.

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MPEG-4 AVC/H.264 Transfer Syntax

Sup 180 Final Text in June 2015

This supplement describes three 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/H.264 High Profile / Level 4.2 (HiP@Level4.2) for 2D Video will perform consistent with the ITU-T H.264 HiP@Level4.2 specifications except that the use of frame packing formats for 3D video is not allowed.

This will enable the storage of video files with a resolution of 1920x1080 at 50Hz/60Hz.

Transfer Syntax MPEG-4 AVC/H.264 High Profile / Level 4.2 (HiP@Level4.2) for 3D Video will perform consistent with the ITU-T H.264 HiP@Level4.2 specifications.

It should be used for transmitting stereoscopic 3D content with frame packing formats.

This will enable the storage of 3D video files with a resolution of 1920x1080 at 50Hz/60Hz in frame packing format.

Transfer Syntax MPEG-4 AVC/H.264 Stereo High Profile /Level 4.2 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.

The supplement editor K.H. Fleischer walked through the comments of the last version. The changes induced by the comments were discussed, modified according to the discussion in the meeting and accepted.

Consistency improvements in the naming for Blu-ray profiles were incorporated in the supplement.

The supplement was approved for final text.

View details»

RESTful Rendering

Sup 174 Revisit planned for September 2015 Sent out for Letter Ballot

This supplement defines rendering functionality for Restful Services (RS) that is largely equivalent to the functionality in the URI and WS services.

It defines Retrieve Rendered and Retrieve Rendered Presentation State transactions for Restful Services. These transactions allow a user agent to retrieve rendered images and other instances in non-DICOM media types from an origin server.

In response to a user agent's request, the origin server will render DICOM instances (images, video, reports, etc.) and encode them in consumer format media types. Almost all consumer formats require remapping the pixel depth to 8 bits.

Security is beyond the scope of the RESTful services defined in this supplement. However generic Web security mechanisms are fully compatible.

The editor J. Philbin walked through the supplement line by line. Minor changes and language improvements were done according to the discussion with working group 6 members.

Different approaches to rendering of images with presentation states were discussed. The retrieved rendered presentation state service describes query parameters in this area.

The supplement was voted ready to go out for letter ballot.

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MR Diffusion Tractography Storage

Sup 181 Revisit planned for September 2015
Sent out for Letter Ballot

This Supplement to the DICOM Standard specifies a new DICOM Information Object for storing magnetic resonance diffusion tractography (MR DT) results (tracks and measurements), which is referred to as MR Diffusion Tractography IOD. It also includes the corresponding Storage SOP Class so that this IOD can be used for network and media storage exchanges.

A tracking algorithm produces tracks (i.e. fibers), which are collected into track sets. A track contains the set of x, y and z coordinates of each point making up the track.

Depending upon the algorithm and software used, additional quantities like Fractional Anisotropy (FA) values or color etc. may be associated with the data, by track set, track or point, either to facilitate further filtering or for clinical use.

Descriptive statistics of quantities like FA may be associated with the data by track set or track.

Examples of tractography applications include:

  • Visualization of white matter tracks to aid in resection planning or to support image guided (neuro) surgery;
  • Determination of proximity and/or displacement versus infiltration of white matter by tumor processes;
  • Assessment of white matter health in neurodegenerative disorders, both axonal and myelin integrity, through sampling of derived diffusion parameters along the white matter tracks.

The editor S. Flossmann presented the latest changes from the open issues and comments from the last version. A walk through of the document with focus on the changes was done.

It was decided to reduce the complexity of the supplement, by constraining the use of sequences on point level. This change has a large impact on the object.

The supplement was voted approved for the letter ballot process.

View details»

Brachytherapy Delivery Instruction

Sup 184 Revisit planned for September 2015
Sent out for Public Comments

The modifications introduced by this supplement describe worklist support for the brachytherapy treatment management and treatment delivery systems. Intention is to offer similar level of support for brachytherapy treatment workflow as was introduced for the external beam radiotherapy in supplement 74: Utilization of Worklist in Radiotherapy Treatment Delivery.

This is achieved by the addition of the following:

RT Brachy Application Setup Delivery Instruction Storage Composite IOD, which contains the data necessary to instruct a treatment delivery device on what is to be delivered.

The key element of the IOD is the RT Brachy Delivery Instruction Module, which contains information on the RT Plan to be used, the channels within the plan that will actually be delivered or omitted.

This supplement is being driven by the desire to address the lack of support for brachytherapy treatment delivery workflow in the current standard.

The supplement was voted to go out for public comments.

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Content Evaluation Results IOD

Sup 185 Revisit planned for September 2015
Sent out for Public Comments

This Supplement specifies the IOD representing content assessment against reference information. It stems from the development of the Quality Assurance with Plan Veto profile in IHE-RO. While the profile 10 originated from use cases to assess RT Plan, the IOD is generalized to allow for reporting of assessment results of any DICOM SOP Instance.

There was an initial discussion of the motivation for the supplement and the proper naming of it.

The level of concern was discussed and modelled. The levels decided upon are major, moderate, minor.

The supplement was voted ready for public comment.

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Preclinical Small Animal Imaging Acquisition

Sup 187 Revisit planned for September 2015
Sent out for Public Comments

This Supplement defines use-cases and templates for storage of information related to acquisition of small animal images during preclinical research.

In some cases, information about the acquisition that is relevant to the interpretation of the imaging may not be known to the modality. This is particularly the case in small animal preclinical research, where a myriad of factors that affect quantitative analysis need to be recorded, which would be overwhelming if required to be captured at the modality console user interface.

The type of information to be recorded needs to be in a structured form, and many of the concepts are expected to be available in external lexicons. This is particularly the case for descriptions of experimental conditions, animal physiology and animal handling. Accordingly, the DICOM Structured Report (SR) mechanism is a natural choice of encoding.

This supplement defines a new DICOM SR root template and supporting templates, as well as an IOD and SOP Class specific to that template to facilitate interoperability.

The editor D. Clunie walked through the supplement text explaining the ideas used and choice of language.

The supplement was voted to be ready to go out for public comments.

View details »

Protocol Storage (CT)

Sup 121 Revisit planned for September 2015

This Supplement defines a pair of storage SOP Classes to distribute planned CT protocols and to record performed CT protocols:

  • a Defined Protocol SOP Class that describes desired values (and/or value ranges) for various parameters of an acquisition and reconstruction procedure. Defined Protocols are independent of a specific patient. Defined Protocols are typically specific to a certain scanner model and/or version (identified by device attributes in the protocol), but model-non-specific protocols are not prohibited. (See USAGE section below)
  • a Performed Protocol SOP Class that describes the values actually used in a performed acquisition. Performed protocols are patient-specific.

The SOP Classes address details including:

  • patient preparation & positioning
  • equipment characteristics
  • acquisition technique
  • reconstruction technique
  • preliminary image handling such as filtering, enhancement, auto-sending, etc.

The changes from the last review was presented by the editor K. O'Donnell. A line by line review was performed.

A discussion took place regarding assertion of validity for a protocol. Especially the modelling and recording of approval information was discussed in detail.

Different classes of protocols were discussed; for production, for research, actively in flux protocols. The last category contains in work protocols which are not yet approved for use in a production workflow.

It was decided to move the approval part into a separate IOD.

An elaborate discussion took place in the context of codes regarding research and production cases.

A discussion took place regarding if changing a protocol is ok. There were three levels discussed, where more and more supervisory rights are needed according to the level:

  • Advisory
  • Strict
  • Enforced

The review of the supplement will continue in September. The plan is to reach the quality for letter ballot voting after the September meeting.

View details »

Imaging Agent Administration

Sup 164 Revisit planned for November 2015

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.

This supplement defines SOP Classes and IODs for persisting and communication of information relevant to the administration of imaging agents used in medical imaging examinations. Furthermore, the supplement is constructed so as to convey planned and delivered Imaging Agent administration using manual methods or automated power-injector devices.

The name of the supplement was challenged as there are many substances not covered. It was proposed to narrow the name to imaging agents.

A line by line walk through was performed with many minor improvements.

The review of the supplement will continue in September.

View details »

Multi-Energy CT

Sup 188 Revisit planned for September 2015
Initial presentation

A slides overview was presented laying out the corner stones for what the working group wants to achieve with this supplement.

Multi Energy Imaging was defined in the presentation:

Imaging techniques, including scanning, reconstruction, processing, when the scanner utilizes multiple energies from the X-Ray beam spectrum, as opposed to the conventional CT imaging, when a single (accumulated) X-Ray spectrum is used. The existing CT and Enhanced CT (eCT) IODs do not adequately describe the new CT multi-energy imaging. Although different vendors apply different scanning and detection techniques to achieve multi-energy images, there is large commonality in the generated diagnostic images.

The main clinical use cases were presented:

  • Allowing better differentiation of materials that look similar on conventional CT images, e.g., to differentiate Iodine and Calcium in vascular structures.
  • Eliminating acquisitions such as non-contrast acquisition, when the virtual/artificial non-contrast image is generated from the contrast image

The main question discussed was to extend the current CT images or to create new additional IODs. The advantage with extending is the easy adaption in the industry, the risk is that images are poorly understood by older multi energy un-aware applications.

The advice was to go the only pragmatic way and to add attributes to the ordinary CT image IOD.

The highest risk of misinterpretation is when one study contains only one virtual multi energy image.

A discussion took place of how to add attributes of type 1 inside a conditional makro or conditional module, which is conditionally mandatory for the multi energy case.

The advice from working group 6 regarding original and derived is to tag everything as original as far as possible.

The document is planned to be prepared for a first read in the September meeting for working group 6.

View details »

Multi Spectrum WSI

Sup MultiSpectralWSI Revisit planned for September 2015
Initial presentation

A slide set was presented explaining the concept and background for this supplement.

Reasons for creating this supplement is to improve true color rendering with 4 or more channels standardize exchange (reproduce pseudo color images, channel un-mixing while preserving raw data, color reproduction under different illuminant) e.g.

  • Multi channel color images, up to 5 channels seen
  • Multi spectral fluorescence images

The following use cases were presented:

  1. Display multi spectral images as true color visible light images
  2. Ability to define how to un-mixed multi spectral input channels for deriving quantative representation of biomarkers intensities
  3. Define how to display unmixed multi spectral fluorescent output from 2 as input for this mode.

The use cases 1 and 3 can be done with ICCv4 input profile, but not number 2.

The goal is to find a way to effectively store multi channel image data.

A discussion on intellectual property rights in the area of this supplement took place. There are two patents in this area, one basic and one specific. Danaher is the holder. Supplement 145 is affected.

It was suggested to the working group for this supplement to investigate the usage of mechanisms from the MPR Presentation State supplement.

The review of the supplement will continue in September.

View details »

Patient Radiation Dose SR

sup PatientRDSR Revisit planned for September 2015
Initial presentation

The goal of the supplement was presented:

  • To store the results of the patient organ dose calculations of a single procedure including one or more modalities and procedure steps/phases.

The variation points are:

  • Covering one or more organs.
  • By one or more calculation methods.

The final goal is to store the final results in the patient record and to exchange intermediate results with peers.

There are different Types of procedures:

  • Single modality, single procedure (studies with only one phase) CT, XA, XRF, Mammo, CR, DX, NM, PET
  • Multi modality, single procedure (multi phase concept) SPECT, PET/CT internal organ dose (stochastic)
  • Single modality, multi procedure (multi phase concept)

The review of the supplement will continue in September.

View details »

CPack 81

WG-06 approved Final Text in June 2015

CPack 82

Current candidates for final text in September 2015

CPack 83 candidates

Current candidates for final text in November 2015
1364 Minor corrections to WADO-RS and STOW-RS 1431 Add Beam Effective Dose in RT Fraction Scheme Module 1432 Add Support for Ion Therapy Scanning Modes 1451 Remove retired Point Index List attributes in PS3.5 Annex A 1452 Correct Recommended Presentation Opacity explanation 1457 Identification of groups of pre-clinical research small animal subjects 1463 Clarify Enhanced US Volume Image and Frame Type Values 3 and 4 1464 Add reference region segmentation property type 1465 Add type of finding to measurement SR templates 1466 Add session to measurements group 1467 Correct time point context relationship 1468 Add defined CID for modality in image library 1469 Remove duplicate rows referencing source image or series for segmentation in volumetric ROI 1470 Small animal anatomy for pre-clinical research 1471 Generalize clinical trials attributes to refer to any type of research 1472 Additional responsible persons 1473 Transverse positioning of pre-clinical research small animal subjects 1475 Add patient defined term for Ultrasound Acquisition Geometry 1476 Add settling phases information and Synch pulse for Functional MRI 1477 Angles for Positioner with Digital Detector 1478 Identification of species and strain of pre-clinical research small animal subjects 1480 Allow multiple items in the MR Receive Coil Sequence 1486 Add RT Ion References 1487 Add Display Origin Coordinates To RT Plan 1488 Clarify RT Image Exposure Attributes in case of MPEG Encoding 1489 Correct description of Surface Scan IOD 1490 Update top level DICOM diagram for Web Services 1491 Incorrect terms in Part 18 Sections 8.2.5 and 8.2.6

Clicking on one specific Change Proposal above will take to that actual content.

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