September 2016 Bjoern.Nolte@siemens.com

Here are the summary notes from the most recent DICOM Base Standard Meeting (WG-06).

WG-06 meets five times a year to do technical review and harmonization of the output from the 31 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).

CT Protocol

Sup 121 100% Final Text

This Supplement defines a pair of storage SOP Classes to distribute defined CT protocols and to record performed CT protocols. It also defines a Query and Retrieve service and the corresponding C-FIND behavior.

The two storage SOP Classes are:

  • CT Defined Procedure Protocol Storage SOP Class that describes desired values 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.
  • CT Performed Procedure Protocol Storage 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 and positioning
  • Equipment characteristics
  • Acquisition technique
  • Reconstruction technique
  • Preliminary image handling such as filtering, enhancement
  • Results data storage (auto-sending)

The primary goal is to set up the scanner, not to script the entire behavior of the department, or the scan suite. The protocol object supports simple textual instructions relevant to the protocol such as premedication, patient instructions, and so on.

The supplement also introduces a Private Data Element dictionary to permit description of scanner model characteristics and the ongoing addition of system-specific features and configurations.

There is no requirement that a scanner should be able to run a protocol from another scanner.

The supplement was voted ready to become part of the standard (final text).

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RT Prescription2.GEN

Sup 147 80% pre trial use

This supplement addresses the need for a new generation of IODs and processes required for use in Radiotherapy. Since the development of the initial Radiotherapy IODs, both Radiotherapy practice and the DICOM Standard itself have evolved considerably, in particular, workflow management.

The key relevant points are:

  • Image IOD development follows the "enhanced multi-frame" paradigm, rather than stacks of 2D SOP Instances.
  • Different representations of data are encoded in different IODs, in contrast to first-generation objects.
  • The worklist mode of operation does place constraints on the architecture. For example, it implies the existence of one or more workflow servers that have knowledge of department-wide scheduling.

A continued detailed walkthrough of the supplement was performed. Almost all of the document was covered.

The clarity regarding "Combining segments" was improved, especially the structure in the defining table.

The supplement is close to ready for clinical trials use. It will be revisited in November.

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Contrast Agent

Sup 164 40% In work

The function of this extension to the standard is to cover the administration of imaging agents.

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

There are three types of Structured Report objects proposed:

Defined - definition of generic administration protocols.

Planned - represents patient specific plans to deliver the imaging agent.

Performed - reporting the actual administration delivered during a medical imaging study. The operator may program a delivery system with an intended delivery. This program is captured in this object. The actuals may deviate from the programmed plan based on a variety of factors. The actual delivery is captured in this object.

There was no discussion or update to the supplement.

In November the plan is to get ready for public comments.

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Adult Echo

Sup 169 100% Final text

This supplement to the DICOM Standard introduces a simplified SR template for Adult Echocardiography Measurements.

It provides similar content to that of TID 5200 "Echocardiography Procedure Report" while addressing details that were the source of interoperability issues.

In particular it provides, with varying degrees and patterns of pre- and post-coordination, multiple codes for the same concept and numerous optional descriptive modifiers.

The new template is driven significantly by ASE Guidelines (http://asecho.org/ase-guidelines-by-publication-date).

The comments from the letter ballot phase were discussed.

The model of fully pre-coordinated terms from the dictionary LOINC was discussed in the context of clearly defining values using structured templates.

The supplement was voted ready to become part of the standard (final text).

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RT C-Arm Treatment2.GEN

Sup 175 50% Public Comment requested

The scope of this Supplement is on treatment delivery and it introduces the concept of RT Radiations along the RT Radiation Set IOD.

  • The new IODs are designed to support both legacy and new equipment.
  • Compatibility with First-Generation IODs:
  • IODs specific to use cases: Explicit separate IODs have been developed for specific treatment modalities for example Tomotherapeutic, C-Arm, and Robotic beams are modeled separately.
  • Support for new techniques in oncology: Robotic therapy and tomotherapy among others.

The clear scope of the new set of IODs for second generation radiotherapy is:

  • Generality versus Specificity
  • Extensibility (new Treatment Techniques)
  • Precision, Cleanness, Efficiency
  • Reusable Building Blocks
  • Generalized Geometry

The use of properties and characteristics in conjunction with segments was simplified.

The supplement was voted to go out for public comments.

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Multi Energy CT

Sup 188 40% In work

This Supplement defines new types of images generated by CT scanners using multiple energies from the X-Ray beam spectrum.

The primary focus of this supplement includes:

  • Making Multi-energy information available to rendering, processing applications and clinical display.
  • Allowing better differentiation of materials that look similar on conventional CT images, for example to differentiate Iodine and Calcium in vascular structures.
  • Accurate description of virtual non-contrast acquisition, when the "virtual/artificial non-contrast" image is generated out of the contrast image.

Important objectives for this supplement include:

  • To facilitate fast and easy adoption by adapting conventional CT and enhanced CT image IODs with multi energy attributes.
  • Minimize misinterpretation risk when these images are displayed on equipment only suitable for conventional CT images.

The introductory slide set was presented and discussed. It was suggested to add clinical examples of potential misinterpretation.

The topic of mean photon energy and calculated energy values for photon bins was elaborated upon.

In November the plan is to get toward ready for public comments.

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Parametric Blending

Sup 189 40% In work

This supplement introduces Parametric Maps to store the quantification of a specific measurement.

The Parametric Blending Presentation State is defining the blending of the content of the different Parametric Maps with optionally an anatomical image as underlay.

This way showing the measurements (like BOLD fMRI, Diffusion parameter maps, CT/MRI Perfusion parameter maps, FDG PET map) in relation to the anatomical structure.

Displayed Area and Graphic modules are present to allow the user to add graphical information related to the blending operation. Like marking the Motor Cortex based on the parametric map.

The usage will be described by using an example of an fMRI study in a new chapter in PS 17 as Informative Annex.

A suggestion was raised to consider the concept of enhanced blending and display pipeline from ultrasound (See DICOM Part 3 and Part 17). A graph illustration helps the implementers greatly.

A discussion took place regarding if this supplement leans toward dynamic controlling or more final frozen presentation states. The suggestion from working group 6 was to go for dynamic behavior.

In November the plan is to get toward ready for public comments.

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View overview slides »

Patient Radiation Dose

Sup 191 60% before Letter Ballot

This Supplement describes a structured report, which records the estimated radiation dose to a patient.

The supplement includes radiation dose from CT, projection X-Ray, and radiopharmaceutical administration (diagnostic and therapeutic).

Occupational radiation exposures and dose from external beam therapy, ion beam therapy, or brachytherapy is out of scope.

There are multiple methodologies and models that can be used to estimate patient dose and these methods are rapidly changing.

Yet, once an estimate of the radiation dose absorbed by a patient is performed, the storing and transferring in a standard format is needed for the radiation source data, method used, parameters used within the method and the resulting dose estimate.

The approach taken here for the Patient Radiation Dose Structured Report (P-RDSR) is to define a new Structured Report (SR) object template and SOP Class.

This SR object, independent of the images or the MPPS, could be routed to an appropriate Dose Information Reporter System.

Slides were presented reflecting the current state of the concept discussions. Especially the goals of flexibility for the Patient Dose SR were made clear:

Store the results of Patient Organ Dose calculations:

  • Store a SINGLE procedure or MULTIPLE procedures
  • Including one or more modalities and procedure steps/phases
  • One or more organs
  • One or more calculation methods

A discussion took place on which grouping to use. Possibilities include grouping on organ, grouping on method used and combinations. There was no final conclusion.

A line by line review from the beginning of the document was started.

In November the plan is to get ready for letter ballot voting.

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View overview slides »

Protocol Approval

Sup 192 70% Letter Ballot

This Supplement defines a storage SOP Class to record and convey approval (or disapproval) of DICOM Defined Procedure Protocol instances.

The nature, basis and scope of the approval depends on the semantics of the codes used in the assertion.

Specific codes and examples are provided for assertions about CT Protocols.

Constraints (how strict shall a protocol be?) regarding families of scanners and reusing protocols triggered a discussion.

This lead to the problem space of matching scanner models/families with the scope of protocols within an institution.

Further the use of the clinical trial module for experimental procedures outside clinical trials was suggested to be described.

The question arose which level of detail and structure to document regarding approval: Clinic, institution, department and hierarchy of responsibility.

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

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View overview slides »

RESTful Non-patient

Sup 194 70% Letter Ballot

This supplement defines Restful Services (RS) for retrieving, storing, and searching for non-patient related IODs such as hanging protocols, color palettes, procedure protocols.

The transactions defined for this service are very similar to those defined for the RS Studies Service. They allow a user agent to retrieve, store, and search for non-patient related IODs from an origin server in DICOM Media Types.

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

The most appropriate root model was discussed. Is it more efficient to have patient and non-patient on the top level or is it patient and other objects?

The comments and resolutions from the public comment phase were presented and walked through.

It was suggested to add a query retrieve example to part 17.

A discussion took place on what return information conveys on what was stored for example additions, modifications and deletions.

The goal is to reach letter ballot quality after an upcoming telephone conference before the November meeting.

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View overview slides »


Sup 195 70% Letter Ballot

To answer the demand for higher 4:2:0 compression efficiency, this supplement adds the following profiles:

  • Transfer Syntax HEVC/H.265 Main Profile /Level 5.1 will perform consistent with the ISO/IEC 23008-2:2016 HEVC Main Profile at Level 5.1. This will enable the storage of video files with a resolution of 4096x2160 at 50Hz/60Hz.
  • Transfer Syntax HEVC/H.265 Main 10 Profile / Level 5.1 will perform consistent with the ISO/IEC 23008-2:2016 HEVC Main 10 Profile at Level 5.1. This will notably enable the storage of video files with a higher dynamic range and a wider gamut space and a resolution of 4096x2160 at 50Hz/60Hz.

HEVC stands for High Efficiency Video Encoding and is a common standard of MPEG and ITU. Please see the following link for details: http://mpeg.chiariglione.org/standards/mpeg-h/high-efficiency-video-coding

HEVC/H.265 has now two associated pools of patents which define royalties to pay for when buying or using HEVC/H.265 codecs.

This supplement is being circulated for letter ballot voting.

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Ophthalmic Angiography

Sup 197 50% Public Comment requested

This Supplement defines "en face" angiography images based upon ophthalmic computed tomography (OCT) technology.

En Face angiography images are derived from images obtained using the spectral domain OCT technology (for example structural OCT images plus angiographic flow volume information).

En Face angiography detects the motion of the blood cells in the vessels to produce images of blood flow in the retina and choroid with capillary-level resolution.

This technology enables a high resolution visualization of the retinal and choroidal vascular network to detect the growth of abnormal blood vessels, and to provide additional insights in diagnosing and managing a variety of retinal diseases including diabetic retinopathy, neovascular age-related macular degeneration, and retinal vein occlusion.

The main features of this supplement are:

  • Updates to the OPT IOD to capture surface segmentation information
  • A new SOP Class to capture the angiographic flow volume images
  • A new SOP Class to encode derived en face images (for example derived from the above two IODs)

An introduction to the different stages, see linked slides for detail, were presented. The detailed description on the data types in the different stages and how they are stored and referenced was explained.

The use of PRIMARY and SECONDARY was questioned as the concept is old. A suggestion to investigate reuse of the parametric map concept was made. The result was to stay with an own IOD as this supplement is very eye-specific.

The quality rating sequence and especially the threshold was discussed. It was suggested to improve the clarity regarding the direction, which values are better and which are worse.

The supplement was voted to go out for public comments.

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View overview slides »

CPack 87

WG-06 approved Final Text in September 2016

CPack 88

Current set for November 2016 Final Text.

CPack 89 candidates

Current candidates for final text in January 2017
Clicking on one specific Change Proposal above will take to that actual content.