A Working Group of Our Own (DICOM WG-26)

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A Working Group of Our Own (DICOM WG-26)

• Bruce Beckwith, MD
• Department of Pathology
• Beth Israel Deaconess Medical Center
• Harvard Medical School
• Boston, Massachusetts

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Current State
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Future State
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Outline

• DICOM overview
• DICOM pathology support
• Use in Pathology
• Issues to address

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DICOM

• Digital Imaging and Communications in Medicine
• Initially drafted as jointly sponsored effort of
  the American College of Radiology and the
  National Electrical Manufacturers Association
  (ACR-NEMA), which became the DICOM committee in
  1998
• Ver. 1 released 1985
• Physical 50 pin hardware abstraction layer
  standard
• Never implemented
• Ver. 2 released 1988
• Initial interest from radiological manufacturing
  community only
• DICOM V3.0 released 1992
• Visible light supplement 1999 (endoscopy/microscop
  y)

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DICOM Governance

• Voluntary standards group
• Housed at NEMA in Virginia
• Currently 26 working groups
• Participants
• Industry
• Professional and trade groups
• Standards developing bodies and government
  agencies
• Anyone who has a material interest

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Pathology in DICOM

• Visible Light working group was initial home
• Created Supp. 15
• Minimal pathology activity since then
• Dec 2005, created a new group for Pathology
  (WG-26)

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Working Group 26

• Open to all interested parties
• 3-4 meetings per year
• 70 subscribers to the mailing list
• 35 organizations
• 9 countries
• Working with IHE (Japan and France) and HL7
  Pathology groups

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DICOM Supplement 15

• Support for
• gross images
• microscopic images
• accession numbers
• case history
• SNOMEDTM nomenclature and others
• some imaging system specifications
• compatible with all DICOM database systems

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How DICOM is Used

• To communicate between image sources
  (radiographic instruments) and PACS
• To communicate between PACS and display
  workstations
• To communicate between RIS and PACS
• To communicate between image sources and
  enterprise image archive

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Image Exchange

• DICOM standard is for communication related to
  digital images
• Uses externally defined file formats to encode
  the image data
• Includes metadata with the image data
• Uses an object oriented data model
• 16-part standard document
• http//medical.nema.org/dicom/2006/

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Typical VL Message Components

• Header Constructs
• Patient demographics
• Study capture parameters
• Equipment parameters
• Pixel/voxel dimensions
• Diagnostic data

Service Class Wrapper
Optional Components

• Structured Reporting Data
• Self-referential XML schemata
• Clinical Data
• Specimen Data
• Tissue Array Data
• Research Access data
• Clinical Trial Data
• Chain of custody data
• .
• Ancillary Schemata/DTD definitions
• Ancillary XML

• Image Data
• Primary image plane data
• Overlay data
• Arbitrary waveform data
• ROI data
• Diagnostic ROI-localized modifier data
• Access/authentication/watermark data

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Picture Archiving Communication Systems

• Store images acquired by multiple instruments
• Serves images to various workstations
• Uses DICOM for messaging
• Typically only utilized for radiology images
• May have workflow limitations

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Enterprise Image Archive

• Centralized storage for medical images
• Share across many departments
• Not limited to radiology or even DICOM
• Not tightly coupled to any workflow
• Can be write once read many (no deletion)

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Imaging Comparison

• Radiology
• digital acquisition
• automatic image capture
• clinician interpretable
• many patient requests
• large storage needs
• digital images save money
• large budgets
• strong standards for storage and transfer

• Pathology
• analog primary data
• manual image capture
• hard to interpret for non-pathologists
• few patient requests
• extreme storage needs
• digital imaging costs more
• modest budgets
• limited pathology specific standards

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Current State in Pathology

• Many PACS vendors are compliant with Visible
  Light images for pathology, endoscopy, etc.
• Growing number of imaging products targeted at
  pathology are DICOM compliant
• Anatomic pathology laboratory information systems
  offer limited image management
• Veterans Administration
• Pathology imaging vendors must be DICOM compliant
  and store images in VISTA PACS
• Small, but growing adoption of DICOM

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Barriers to Adoption of Current Products

• Turf
• PACS systems have traditionally been the domain
  of Radiology
• Movement toward storing all medical images in a
  central location with a single viewing mechanism
  still in infancy
• Workflow
• May need to manually annotate files with image
  description, accession number, etc.
• If sending to PACS, need to order study first
• Cost
• Image acquisition and annotation takes time no
  extra reimbursement currently
• Slide scanners and storage are costly

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Path PACS

• Humin Tec (Korea)
• PACS system for pathology departments
• 21 installations, all in Korea
• Communicates with standard radiology PACS
• Also offers station for specimen photography
• Apollo Telemedicine (USA)
• PACS system allows acquisition and storage of
  images
• Installed at Milwaukee Veterans Administration
  Hospitals
• Images can be stored in VISTA imaging system

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Academic Center Efforts

• Univ. of Pittsburgh
• AP LIS is image aware
• Gross specimen photos and single field
  microscopic images saved
• Transmitted to Enterprise Image Archive
• Clinicians can see only selected images on
  completed cases
• Main clinician interest is specimen photos
• Main pathologist use is conferences

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Issues to Address

• Technical
• Need for additional data elements (block, slide,
  slide status, more detailed imaging system
  description, etc.)
• Support for whole-slide microscopic images
• DICOM is limited to 64k x 64k pixel images
  currently
• Support for multi-resolution (pyramidal) formats
• Support for navigating and selecting a region of
  interest from within entire slide image
• Support for multispectral and hyperspectral
  modality images
• Non-technical
• Suggested workflow and use examples (IHE)
• Support for DICOM from LIS vendors

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Resources

• DICOM web site medical.nema.org
• RSNA DICOM Intro www.rsna.org/Technology/DICOM/int
  ro/index.cfm
• Medical Imaging FAQ www.dclunie.com/medical-imag
  e-faq/html