MINUTES

Joint Meeting of:DICOM Working Group 20 (Integration

of Imaging and Information Systems)

and

HL7 Imaging Integration SIG

Place:Atlanta, GA

Dates:April 29 – May 1, 2002

Members Present (WG 20):

American College of RadiologyFred Behlen – M, T, W

GE Medical SystemsHarry Solomon – M, T, W

IDX SystemsAndrei Leontiev – M, T, W

Merge TechnologiesJohn Fehrenbach – M, T, W

Philips Research LaboratoriesK.P. Lee – M, T

Siemens Medical SystemsHelmut Koenig – M, T, W

Members Present (HL7):

Calvin Beebe – T Mayo Clinic

Ivan Cvekic – M A.L.I. Technologies

Robert Dolin – T Kaiser Permanente

Shashikala Duraiswami – T, WSegami

Martin Kernberg – M, TUCSF

Ed Larsen – T E.R. Larsen, Inc.

Jim Mc Cain -- TVeterans Health Administration

Takashi Nakashima – M, WToshiba

Herman Oosterwijk – T, WOTech

Geoffrey Pascoe – M Philips Medical Systems

Chris Voigt -- TAMS

Members Absent (WG 20):

American College of RadiologyAlan Rowberg

IFA Systems GroupRainer Waedlich

Toshiba CorporationHidenori Shinoda

Others Present:

NEMA StaffHoward Clark – M, T, W

Presiding Officer:Fred Behlen, Co-Chair

Martin Kernberg, Co-Chair

Herman Oosterwijk, Co-Chair

1.Introductions and Agenda Review

Meeting participants identified themselves and their employers.

Referring to the Agenda Status Document (<2002 04 Agenda Grid.00.doc>) that had been circulated in advance of the meeting, Dr. Behlen summarized the status of open items.

2.Review of Previous Minutes

After modifying the attendance list to show Harry Solomon as the voting representative for G. E. Medical Systems with Charles Parisot as the alternate, the minutes were approved as amended.

3.Announcements

Fred Behlen reviewed the history of changes in the structure of the RIM and introduced a revised model (Version 1.15 dated 3/07/2002) that had been introduced earlier in the day at the meeting of the Structured Documents TC. This new form appears to be significantly simpler than previous versions. In the course of the discussion, members identified a need for detailed examples and case studies.

4.Meeting with the SIG on Conformance

Ms. Iona Singureanu, co-chair of the Special Interest Group on Conformance reviewed the current status of the group’s work and mentioned that their most recent accomplishment has been the addition of conformance mechanisms in the Version 2.5 ballot. She noted that V2.5 constraints are to be submitted as XML documents. Members of the Conformance SIG presented an example of a sample message and demonstrated how that message could be converted to a “pdf” format, a Word document or an HTML document. Peter Rontey and other members of the Conformance SIG also demonstrated a special “messaging workbench” that was programmed in the Delphi language and will carry out each of these functions, and can validate message instances against the constraints. The tool also provides support for queries. Together, members of both groups prepared an example HL7 message using the MWB Conformance Parameters tool. Members representing IHE will explore the suitability of these tools for possible use in the 2002 IHE Connectathon, and if successful, the IHE profiles may be submitted to the HL7 conformance repository.

5.SR Content Mapping to RIM Mapping

John Fehrenbach and K.P. Lee presented a chart <SR-RIM Attribute Mapping_Rev2.xls> summarizing the mapping from DICOM attributes to HL7 attributes. Members conducted a detailed review of this chart and modified it as appropriate. The updated version is called <SR-RIM Attribute Mapping_04_30.xls>. Members requested that Mr. Lee work with other members of the Philips staff to continue development of this approach. Also, in the course of this discussion, Martin Kernberg offered to prepare a list of tools that can be used to facilitate SR content mapping.

At one point, Harry Simon offered to create a DICOM Change Proposal that would assign DCM codes to the SR relationships (Part 3 Table C.17.3-2) for use in transcoding to HL7 V.3. Later, however, members determined that such an action would not be necessary because the V.3 relationship types reference HL7 vocabulary domains rather than external code sets. Additional codes that are found necessary will be added through the HL7 RIM Harmonization process.

Considerable time was spent discussing differences in the way that date and time are represented in DICOM and HL7. HL7 V.3 does not define a time of day without a date, except for such time generalizations as business hours represented in the GTS datatype. Some confusion existed between reporting intervals of elapsed time (duration) vs. time of day. Andrei Leontiev offered to attempt a mapping of ambiguous time into the HL7 GTS datatype.

6.R-MIM for CDA Representation of DICOM SR

Dr. Robert Dolin reported on recent progress in developing the procedures for getting SR content into CDA Level 3 with assurance that SR and CDA are fully interchangeable.

As an example of the desire to provide annotation of images, Calvin Beebe reported that some clinicians were seeking a way to show a “scar line.”

Dr. Dolin identified three different ways to express referenced coordinates. As the discussion progressed, however, participants came to agree that such references should be modeled as discrete observations that refer to the referenced coordinate. (In this case, there is a need to add an Act relationship in the R-MIM). Looking to the future, participants see a need to have different types of constraints on a large choice structure.

7.Joint Meeting on Templates with Modeling & Methodology and Structured Reporting

Bob Dolin presented the HL7 Template Proposal that he prepared in conjunction with Peter Elkin, Liora Alschuler, Martin Kernberg, Lloyd McKenzie, Gunther Schadow, CalvinBeebe, Sandy Boyer and Angelo Rossi-Mori. A copy of the document may be found in the file <HL7_Template_Propposal.April24.2002.doc>. The key point of his presentation was summarized in the sentence, “Templates can only constrain the range of allowable expressions made possible by some balloted HL7 specification.” That is, templates are not an extensibility mechanism. They are constraints. According to this proposal, HL7 would provide a registry for templates developed by other professional groups. However, it would not ballot templates produced by external organizations. Control mechanisms were proposed to help assure that the templates are of adequate quality. However, these will require tools and some degree of advisory services to assist newcomers who are not familiar with all of the technical details.

A sample scenario on lab batteries that were to be constrained by using a tabular template representation was presented to demonstrate the detailed methodology. Additionally, the proposal included a scenario on document contents that were constrained, first, by cloning, second by using the constraint box and, finally, by using a tabular template representation.

The proposal also includes a substantial list of Open Issues that need to be addressed as the work proceeds.

Most everyone in the room recognized this effort as an extremely important initiative. Care must be taken to define the appropriate role of HL7 in developing and implementing this approach and the availability of resources to carry out these responsibilities. A question for the future is whether HL7 will ultimately choose to certify specific templates. While some felt that the National Library of Medicine might be a suitable repository for the templates, others thought that the responsibility should not lie with an agency of any one national government.

To help obtain more feedback, a discussion session is planned for Wednesday evening at this meeting. In a straw vote, members of the Modeling & Methodology TC encouraged the group to move forward with the development of this approach with the goal of preparing it for a committee ballot as a normative ballot in October.

8.IHE Procedure Model to RIM Mapping

Helmut Koenig introduced and led a detailed discussion of a Visio document named <hl7V3_imagingIntegrationRMIMsV01visio5.vsd>. Members considered this to be an exceptionally good start at developing this approach. Mr. Koenig will proceed with these efforts and integrate the comments received from members of the group. The group now has a good set of documents from which to begin defining V3 messages for imaging integration. Fred Behlen noted that such message definitions support not only the messaging interfaces in V.3, but are also needed to provide the means to reference images and procedure context in CDA Level 3 documents. Mr. Koenig observed that further progress increasingly requires a RIM Harmonization Facilitator for the group.

9.Mapping of DICOM and HL7 Reporting Schemes

Considerable attention was given to the question of how one can map the seven SR relationships to HL7 RIM concepts. The mapping of SR relationships to Act_relationship was found not to be one-to-one. For example, the SR CODE Content Item maps to an HL7 Concept Descriptor (CD) datatype, whereas the HAS CONCEPT MOD relationship would be represented as a CR datatype post-coordinated modifier in the CD datatype for the Act code.

The group concluded that the mapping process must be driven by good use cases from a variety of domains. In the use cases, the identification of exact RIM class clones and relationships can be more reliably defined.

10.New Business

Fred Behlen introduced a draft DICOM Change Proposal called “Expand Definition of Coding Scheme Designator.” After some discussion, members asked Harry Solomon to introduce this CP at the WG-06 meeting in Nice.

Members devoted a few minutes to reviewing <V2.5 Ballot Feedback Chapter 4.doc>. All issues related to imaging were subsequently resolved at the Orders and Observations meetings on May 3, which Fred Behlen attended.

11.Next Meeting

The next face-to-face meeting of WG-20/HL7-IISIG will be held from September 30 – October 2, 2002 in Baltimore, MD. That meeting will begin at 1:45 PM on Monday and end at 5:00 PM on Wednesday. Subsequent meetings will be held on:

  • January 13 – 15, 2003 in San Antonio, TX,
  • April 28 – 30, 2003 in Cleveland, OH and
  • September 8 – 10, 2003 in Memphis, TN.

In preparation for the next meeting, members reviewed and updated the Agenda-Status report <2002 01 Agenda-Status.02.xls>, which has, now, been labeled <2002 04 Agenda-Status.00.xls>. Fred Behlen will refine and post the revised document to the group’s private ftp site in the folder for this meeting as well as the folder for the September meeting.

12.ADJOURNMENT

The meeting adjourned at 4:45 P.M. on Wednesday May 1, 2002.

Reported by:

Howard E. Clark, Secretary

(05/15/02)

Reviewed by Counsel:

1

DICOM WG-20/HL7 II SIG

April 29 – May 1, 2002