HL7 and DICOM Standards in Taiwan 李友專, M.D., Ph.D. 中華民國醫療資訊學會 台北醫學大學醫學資訊研究所
Problems with Current Status • 編碼系統缺乏一致性及臨床表達能力 • 缺乏一致的資料交換格式 • 結果 • Bad code portability and reusability • Complicated sub-system integration • Hard to upgrade • We need some standards!!!
The nice thing about standard is… There are so MANY to choose from!!!
Medical Information Standard • Many different purposes • For financial transaction, insurance claims, clinical data, images, …etc. • Many different standard organizations • ANSI, ISO (TC215),CEN (TC251), IEEE, ASTM, HL7, DICOM (ACR-NEMA), various medical associations such as CAP, AMA, ADA…etc.
Medical Information Standard(cont.) • Standards for Data Interchange • Allow data to be exchanged among different systems, intra-hospital or inter-hospital • e.g. HL7, DICOM…etc. • Standards for terms, codes and vocabularies • Sets of codes that represents medical terms • e.g. SNOMED, LOINC…etc.
Layers of Standards ISO OSI (Open Systems Interconnection) 7 Layers • Layer 7 – Application protocol • Layer 5, 6 – Session & Presentation protocols • Layer 2,3,4 – Link, Network and Transport protocols – e.g. TCP/IP • Layer 1 – Physical protocol
Text/Multimedia Interchange • HL7 (Health Level 7) • a messaging standard for clinical and administrative data in healthcare • DICOM (Digital Imaging and Communications in Medicine) • a communication standard for bio-medical images
HL 7 • Established in 1987 as a messaging standard for clinical and administrative data in healthcare • 20 technical committees, 17 special interest groups → Technical Steering Committee • Currently in V 2.4.1, transition to V 3.0 • 15 Chapters
HL 7 (cont.1) • V 3.0 (balloting till the end of 2003) • A leapfrog approach • Message Development Framework (MDF) • Reference Information Model (RIM) • Object-oriented models with 126 class, 861 attributes • Can be exchanged as ASCII or XML form • Use of Object Brokerage (CORBA, DCOM)
HL 7 (cont.2) • New development in conjunction with V 3.0 • Arden Syntax Standard (for clinical decision support) • Clinical Document Architecture (CDA) • XML defined EHR, v1.0 transition to v2.0 • Clinical Context Management Specification (CCOW) • ANSI approved, version 1.3 • Vocabulary TC • SNOMED, LOINC (Logical Observation Identifiers Names and Codes)
What is the CDA The HL7 Clinical Document Architecture (CDA) is a document markup standard that specifies the structure and semantics of "clinical documents" for the purpose of exchange. A clinical document contains observations and services and has the following characteristics: • Persistence – A clinical document continues to exist in an unaltered state, for a time period defined by local and regulatory requirements. • Stewardship – A clinical document is maintained by a person or organization entrusted with its care. • Potential for authentication - A clinical document is an assemblage of information that is intended to be legally authenticated. • Context - Contents of a clinical document share a common context unless all or part of that context is overridden or nullified. • Wholeness - Authentication of a clinical document applies to the whole and does not apply to portions of the document without the full context of the document. • Human readability – A clinical document is human readable. A CDA document is a defined and complete information object that can include text, images, sounds, and other multimedia content.
More on CDA • CDA vs. HL7 Messages • A CDA document is a defined and complete information object that can exist outside of a messaging context and/or can be a MIME-encoded payload within an HL7 message.
HL 7 (cont.3) • HL7 Taiwan is now a member nation of International HL7 Affiliate • HL7 Website: • www.hl7.org.tw (Taiwan) • www.hl7.org (US)
DICOM • Created by ACR(American College of Radiology) and NEMA(National Electrical Manufacturers Association) in 1994 as a communication standard for bio-medical images • Driven by real needs, very fast development • Now with 21 Working Groups, including cardiology, ophthalmology, nuclear medicine, dermatology…etc.
DICOM (cont.) • Start from Radiological images, now also • Visible light and sonogram images • 3D images • Radiotherapy objects • Structured reports • Widely available for CT, MRI, CR, DR, Sonogram machines • Quite popular in Taiwan
DICOM (cont.) • Basic requirement for medical imaging device • Now 16 Chapters • Website: • http://medical.nema.org/
DICOM Part 1: Introduction and Overview • DICOM Part 2: Conformance • DICOM Part 3: Information Object Definitions • DICOM Part 4: Service Class Specifications • DICOM Part 5: Data Structure and Semantics • DICOM Part 6: Data Dictionary • DICOM Part 7: Message Exchange • DICOM Part 8: Network Communication Support for Message Exchange • DICOM Part 10: Media Storage and File Format for Media Interchange • DICOM Part 11: Media Storage Application Profiles • DICOM Part 12: Media Formats and Physical Media for Media Interchange • DICOM Part 14: Grayscale Standard Display Function • DICOM Part 15: Security Profiles • DICOM Part 16: Content Mapping Resource
Integrating the Healthcare Enterprise - IHE • IHE was started by RSNA (Radiological Society of North America) and HIMSS (Healthcare Information and Management Systems Society). Now in Year 5 (RSNA 2003 and HIMSS 2004). • Integration framework for DICOM and HL7
IHE technical framework • IHE Infrastructure Technical Framework • Radiology Technical Framework
Vocabulary • UMLS (Unified Medical Language System) • Metathesaurus, from National Library of Medicine (NLM) • SNOMED 3 • from College of American Pathologist (CAP) • LOINC – from HL7 Inc. • ICD9-CM, ICD-10 – from WHO • READ Classification • From NHS of UK
Reusable knowledge • Developed in the 1990s as MLM (Medical Logic Modules) • Arden Syntax • PASCAL-like, rule-based • Columbia University • Now part of HL7 and ANSI Standard
Why NOT Standards • Lack of recognition • Don’t know, don’t care • Less short-term overhead • Takes a lot of time to understand standards • Easier to implement (at first) • Legacy systems • Need to be retrofitted
Why Standards • Interchangeability • Manageability • Subsystems can be upgraded independently • Integration • Pick the best of breeds • Competitiveness • Med info industry
Integrated Effort • Government • Legislation issues • Funding – NHI? • Hospitals/Clinics • Think Big, start small • Industry • Get involved at the early stage • Schools • Localization • Find out what we can/cannot use
Integrated Effort (cont.) • HL7 Taiwan has been formed through the help of 中華民國醫療資訊學會 in 2000 • 生物醫學工程學會 has joined the DICOM committee, now DICOM Taiwan in 2003 • More effort needed to sustain its future operation
For More Information • http://www.medinfo.org.tw/ • http//www.hl7.org.tw/ • http://www.dicom.org.tw/