DICOM Ontology

(DO) UpdateBuilding a cathedral, one

grain of sand at a time

March, 2009

Daniel Rubin M.D., M.S.Assistant Professor of Radiology

Stanford University

David S. Channin, MDAssociate Professor of Radiology

Northwestern University

Curtis P. Langlotz, MD, PhDAssociate Professor of Radiology

University of Pennsylvania

Charles E. Kahn, Jr., MD, MSProfessor of Radiology

Medical College of Wisconsin

Presenters

DICOM

• DICOM is the global standard for medical imaging• Comprises 20+ years of combined knowledge

from engineers and radiologists from academia and industry

• 16 Parts; Over 125 Supplements; 3583 PAGES!• Subsets of DICOM used extensively in many

caBIG Imaging Workspace projects• Current DICOM standard not computationally-

accessible to reuse; limits interoperability

Needed by many,understood by few

• DICOM lacks a computable reference information model• Hinders interoperability in applications• Inconsistent use of controlled terminology or relations

• Specified in PDF documents; not computable• Duplication of effort in workspace projects• Potential conflicts among different models that represent

same imaging information

• DICOM is HUGE• time consuming to review and understand

DOverview: Death by Bureaucracy

• DO Phase I FY08• Planning contract

• DO Phase II FY09• Pilot Ontology development of 1 IOD (CT)

• DO Phase III FY10 ??• IODs 2,3,4,5,6

• DO Phase IV FY11 ??• IODs 7,8,9,10,11

• DO Phase V FY12 ??• IODs 11,12,13,14,15

• • • DO Phase XIV FY20 ??

• IODs 50,51,52,53,54• DO Phase XV-XX FY21-FY26 ?? (DSC,DLR,CPL,CK retire at age 65)

• New IODs since FY10

Overview of Phase II (FY09)

• Purpose: Develop a unified knowledge model based on the scope of radiology domain in DICOM

• Scope: DICOM is BIG; project is scoped initially to reviewing/modeling one IOD (CT)

• Goals: Develop prototype ontology and begin developing synergies with existing projects

Phase II Goals

• Produce initial skeletal structure of the DICOM ontology based on reviewing a single Information Object Definition (IOD)

• Create DICOM ontology containing the entities and relations needed to describe the IOD content.

• Define approach to generalize our approach to extend DICOM ontology to rest of the DICOM standard

Project Tasks

• Identify and review pertinent portions of DICOM: Focus on a single IOD

• Review E-R diagrams in DICOM: Identify elements incorporate into the oncology

• Reconcile DO for modeling inconsistencies in DICOM• Compile ontology components: Enumerate the key

terms comprising the ontology, and identify the content that should be modeled as classes and relations

• Build initial DICOM Ontology: Translate relevant portions of DICOM standard into a structured format that can be imported into an ontology authoring tool such as Protégé

DO Progress

• Reviewed CT IOD and DICOM standard• CT IOD• Relevant parts of DICOM extracted from part 6,

part 3 and some of part 16• Produced initial DICOM ontology

• Patient (Study, Series, and Image remain) • DICOM Modules and Macros• DICOM Data Dictionary

• Data Elements and Data Element Types

Raw CT IOD in DICOM

DICOM Ontology in Protege

Patient Module in DICOM

Patient Name in DICOM Ontology

Questions?