RSNA 2005 – infoRAD Defining Clear and Complementary Roles for HL7 CDA (Clinical Document Architecture) and DICOM SR (Structured Reporting) in Diagnostic Reporting Fred M. Behlen, PhD American College of Radiology Co-Chair, DICOM Working Group 20 & HL7 Imaging Integration SIG Co-Chair, HL7 Structured Document TC President, LAI Technology, Homewood, IL Harry Solomon GE Healthcare Co-Chair, DICOM Working Group 1 Co-Chair, IHE Cardiology Technical Committee

2 Disclosure Fred Behlen –Employee, LAI Technology (Laboratory Automation Inc.) Shareholder, Director, Officer Partner, Migratek Data Migration Services Consultant, XStor Medical Systems Harry Solomon –Employee, GE Healthcare

3 Acknowledgements Bob Dolin, Liora Alschuler, Calvin Beebe – co- chairs of HL7 Structured Documents Technical Committee, and authors of presentations on CDA used in this talk Dave Clunie – former co-chair of DICOM Standards Committee, and author of the definitive book on DICOM Structured Reporting

4 Objectives Understand the HL7 CDA (Clinical Document Architecture) and its use cases Understand DICOM SR (Structured Reporting) and its use cases, including Key Image Notes, Evidence Documents and CAD (Computer Aided Diagnosis) results Understand the workflows for reporting, and the appropriate places for DICOM SR and HL7 CDA in those workflows See example implementation scenarios

5 HL7 Clinical Document Architecture Overview

6 HL7 Clinical Document Architecture The scope of the CDA is the standardization of clinical documents for exchange. A clinical document is a documentation of observations and other services with the following characteristics: –Persistence –Stewardship –Potential for authentication –Wholeness –Human readability A CDA document is a defined and complete information object that can exist outside of a message, and can include text, images, sounds, and other multimedia content.

7 CDA History 1996 – initial discussions 1997 – HL7 SGML SIG –Use of Standard Generalized Markup Language for adding metadata to documents –Later evolved to Extensible Markup Language (XML) subset of SGML –Kona Editorial Group 1998 – Patient Record Architecture draft 2000 – Clinical Document Architecture Release 1 adopted –Limited to “level 1” 2000 – SIG becomes HL7 Structured Documents Technical Committee 2005 – Clinical Document Architecture Release 2 adopted –Expanded to “levels 2 & 3”

8 CDA Use Cases Diagnostic and therapeutic procedure reports Encounter / discharge summaries Patient history & physical Referrals / prescriptions Uniform format for all clinical documents

9 Key Aspects of the CDA CDA documents are encoded in Extensible Markup Language (XML) CDA documents derive their meaning from the HL7 Reference Information Model (RIM ) and use HL7 V3 data types A CDA document consists of a header and a body –Header is consistent across all clinical documents - identifies and classifies the document, provides information on patient, provider, encounter, and authentication –Body contains narrative text / multimedia content (level 1), optionally augmented by coded equivalents (levels 2 & 3)

10 CDA Standard Release 1 (2000) –Standalone standard –Based on draft v3 RIM –Level 1 narrative and multimedia Release 2 (2005) –Incorporated into HL7 v3 Standard (Normative Edition just published on CD) –Level 2 narrative and multimedia, plus coded statements Implementation Guide for Care Record Summaries, US Realm (currently in ballot)

11 CDA Release 2 Information Model HeaderBody Participants Sections/ Headings Clinical Statements/ Coded Entries Extl RefsContext ID/ Type Start Here

12 CDA Structured Body Structured Body Section Text Section Text Section Text Section Text Section Text Section Text Entry Coded statement Entry Coded statement Entry Coded statement Arrows are Act Relationships Has component, Derived from, etc. Entries are coded clinical statements Observation, Procedure, Substance administration, etc.

13 Clinical Document Characteristics Persistence –Documents exist over time and can be used in many contexts Stewardship –Documents must be managed, shared by the steward Potential for authentication –Intended use as medico-legal documentation Wholeness –Document includes its relevant context Human readability –Essential for human authentication

14 Sample CDA

15 Narrative and Coded Info CDA requires human-readable “Narrative Block”, all that is needed to reproduce the legally attested clinical content CDA allows optional machine-readable coded “Entries”, which drive automated processes Narrative may be flagged as derived from Entries –Textual rendering of coded entries’ content, and contains no clinical content not derived from the entries General method for coding clinical statements is a hard, unsolved problem –CDA allows incremental improvement to amount of coded data without breaking the model

16 Narrative and Coded Entry Example

17 DICOM Structured Reporting Overview

18 DICOM Structured Reporting The scope of DICOM SR is the standardization of documents in the imaging environment. SR documents describe or reference images, waveforms, or specific regions of interest.

19 SR History 1994 – initial discussions 1995 – Working Group 8 (Structured Reporting) 1998 – Supplement 23 Structured Reporting draft – Supplement 23 adopted 2001 – Supplement 53 DICOM Content Mapping Resource adopted – 12 Supplements defining specific SR document templates

20 SR Use Cases Radiology reports with robust image / ROI references Measurements/analyses made on images Computer-aided detection results Notes about images (QC, flag for specific use, quick reads) Procedure logs for imaging-based therapeutic procedures Image exchange manifests

21 Use Case Common Features Structured –Lists and hierarchies Numeric measurements, coded values –Automatically extractable for database, data mining Relationships between items –Hierarchical, or arbitrary reference –Power of rich semantic expression References to images, waveforms, other objects –Collected in DICOM environment Explicit contextual information –Unambiguous documentation of meaning

22 Key Aspects of DICOM SR SR documents are encoded using DICOM standard data elements and leverage DICOM network services (storage, query/retrieve) SR uses DICOM Patient/Study/Series information model (header), plus hierarchical tree of “Content Items” Extensive use of coded content –Allows use of vocabulary/codes from non-DICOM sources Templates define content constraints for specific types of documents / reports

23 SR Content Item Tree Root Content Item Document Title Content Item Arrows are parent-child relationships Contains, Has properties, Inferred from, etc. Content Items are units of meaning Text, Numeric, Code, Image, Spatial coordinates, etc. Content Item

24 DICOM SR Objects Basic Text –Narrative text with image references Enhanced and Comprehensive –Text, coded content, and numeric measurements, spatial and temporal ROI references Mammo CAD and Chest CAD –Automated analysis results Key Object Selection (KO) –Flags one or more images or waveforms with purpose (for referring physician, for surgery …) and textual note –Used for key image notes and image manifests (in IHE profiles) Procedure Log –For intravascular / cardiac cath

25 Radiology Reporting

26 Reporting Integration Should be high priority –Economic importance of radiologist productivity –Referring physicians (radiology’s customers) want to see key images But, still mostly served by proprietary and custom integration

27 Reporting integration includes: Workflow –Managing interpretation worklists –Providing orders and relevant clinical information –Automatically displaying appropriate images and relevant priors Annotation and measurements –Key images –Markings, measurement calipers and other graphical annotation –Measurements acquired in the imaging procedure Structured reporting Narrative reporting

28 The all-DICOM solution DICOM SR, along with General Purpose Worklist, was supposed to take care of all this. DICOM SR has found vital uses in key subspecialty areas that produce structured data in the examination or post- processing –Cardiology, both Cath Lab and Echo –Fetal biometry in ultrasound –Computer Aided Detection/Diagnosis results These SR documents are not necessarily part of the patient’s medical record, but are part of the Evidence Data.

29 “Evidence” and “Reports” Evidence Documents –Include ultrasound measurements, cath lab procedure logs, Computer- Aided Diagnosis results, etc., that are created in the imaging context –Together with images, are part of the information that a radiologist uses to produce a report –The reporting physician may quote or copy parts of Evidence Documents into the report, but doing so is part of the interpretation process at the reporting physician’s discretion –Appropriate to be stored with the images as DICOM SR objects Reports –Become part of the patient’s medical record, with potentially wide distribution –Ideal match to HL7 CDA; structured/coded data requires CDA Release 2

30 Reporting is RIS Turf Diagnostic reporting continues in the province of information systems that are based primarily on Health Level Seven (HL7) standards. Even if diagnostic reports were created as DICOM SR objects, the end recipients of diagnostic reports – referring physicians – commonly use systems with HL7 rather than DICOM capabilities.

31 DICOM-HL7 Synergy SR and CDA developed simultaneously DICOM and HL7 working groups recognized the need to work together  DICOM SR and HL7 CDA are congruent in key areas –Document persistence –Document identification, versioning and type code –Document’s relation to the patient and to the authoring physicians In 2000 DICOM groups were already looking to CDA as a format for exporting DICOM SR content –Proposal to translate SR documents into CDA, but would have to wait (a long time) for Release 2 Level 3 of CDA

32 DICOM Interest in CDA Use cases for varying types and purposes of diagnostic reporting elaborated at the DICOM 2002 Symposium. March 2003: DICOM Working Group 10 (Strategic Advisory) suggested composing the reports directly in CDA format. Standards solutions were considered against the use cases, and gaps were identified and subsequently closed through extensions to the standards. The efforts have included: –discussions in many working groups of DICOM –continued cooperation with the HL7 Structured Document Technical Committee, which edits the CDA –the issuance of DICOM Supplement 101 (HL7 Structured Document Object References) –CDA Implementation Guide for Diagnostic Reports [2006]

33 Standards Now Ready CDA Release 2 is now published [2005], and all needed standards are now in place. Additions to DICOM in Supplement 101 –Enable reference to CDA documents from within DICOM objects –Include CDA documents on DICOM removable disks Indexed in DICOMDIR for integration with DICOM storage systems –Communicate simple image references and annotation from PACS to reporting systems without requiring close integration of the two systems

34 User control Diagnostic reporting Image Viewing Application Reporting Application PACS Archive Information System Diagnostic report Report Image Sources Orders, Prior Reports Diagnostic Images Viewing settings

35 Report with image references & annotation User control Reporting with annotation (use case) Image Viewing Application Reporting Application PACS Archive Information System Diagnostic report Image Sources Diagnostic Images Image references & annotation Viewing settings Orders, Prior Reports

36 User control Reporting with annotation (available) Image Viewing Application Reporting Application PACS Archive Information System Diagnostic report Report Image Sources Diagnostic Images Viewing settings, image references & annotation Image references & annotation Orders, Prior Reports

37 Diagnostic report Integrated solution Image Viewing & Reporting Application Integrated PACS & Information System Image Sources Orders, Diagnostic images & Prior reports Viewing settings, Reports, image references & annotation Image references & annotation User control

38 User control Loosely integrated reporting Image Viewing Application Reporting Application PACS Archive Information System Diagnostic report Report Image Sources Diagnostic Images Viewing settings, image references & annotation Image references & annotation Orders, Prior Reports

39 User control Loosely integrated reporting Image Viewing Application Reporting Application PACS Archive Information System Diagnostic report Report Image Sources Diagnostic Images Viewing settings, image references & annotation Image references & annotation Image retrieval Orders, Prior Reports

Transcribed narrative Verification Image selection Annotation Image Viewing ApplicationReporting Application Image Archive (DICOM SCP) Reporting System Validation Functions Dictated report DICOM KO object “For Report” DICOM Query/Retrieve for all KO objects matching Accession Number WADO Server Reporting Integration Functions CDA Report SR Report DICOM references to Images & GSPSs WADO URI references to Images with GSPSs DICOM GSPS object

41 CDA Implementation Guides Balloted as HL7 Informative Documents Describe what amount to “templates” for CDA Documents. –Specify constraints on CDA content –Provide Schematron validation of instances –Each Implementation Guide has a Template ID attribute that is included in the root element of the conforming document Care Record Summary IG being balloted WG20/IISIG is preparing an IG for Diagnostic Imaging Reports

42 Conclusions CDA now being seen as primary format for diagnostic reports –Supp 101’s definition of SR report and its equivalent CDA is most practical at this time, though the CDA structure is not normative text in DICOM –Direct definition of CDA report to be done in 2006 by a balloted HL7 Implementation Guide –Does not require tight integration of imaging and reporting workstations –Method is extensible to reports with more structure DICOM SR will see continued and expanding use for Evidence Documents created in the imaging setting –IHE Evidence Documents Integration Profile –Work under way for formalizing Evidence Documents as a separate object class in DICOM