Lessons Learned from the DICOM Standardization Effort David Clunie, Chairman DICOM Standards Committee Harry Solomon, Chairman DICOM Working Group 1 (Cardiovascular Information)

What is DICOM? The pre-eminent international standard for communication of medical digital images and related information The product of 18 years of industry / clinical collaboration, beginning as ACR-NEMA 16 Parts, over 1500 pages A standard that works! Hundreds of products, thousands of devices

The pre-eminent international standard for communication of medical digital images and related information

The product of 18 years of industry / clinical collaboration, beginning as ACR-NEMA

16 Parts, over 1500 pages

A standard that works!

Hundreds of products, thousands of devices

About Standards Development It’s not easy or cheap Intellectual capital, especially in information modelling Consensus building among all stakeholders DICOM - $10’s of millions, thousands of committee hours

It’s not easy or cheap

Intellectual capital, especially in information modelling

Consensus building among all stakeholders

DICOM - $10’s of millions, thousands of committee hours

Organizational Aspects Initial standard development is only a fraction of the total effort On-going demand for interpretation, maintenance, evolution, education Needs a solid organizational infrastructure, focused on the standard itself, for the long term DICOM Standards Committee utilizes the National Electrical Manufacturers Association as Secretariat Major support from RSNA and HIMSS “Integrating the Healthcare Enterprise” initiative

Initial standard development is only a fraction of the total effort

On-going demand for interpretation, maintenance, evolution, education

Needs a solid organizational infrastructure, focused on the standard itself, for the long term

DICOM Standards Committee utilizes the National Electrical Manufacturers Association as Secretariat

Major support from RSNA and HIMSS “Integrating the Healthcare Enterprise” initiative

DICOM Standards Committee 25 manufacturers, plus 2 manufacturers’ organizations (NEMA - US, JIRA - Japan) 15 clinical user organizations (worldwide) radiology, cardiology, pathology, dentistry, opthamology, dermatology, gastro-enterology FDA Center for Devices and Radiological Health National Cancer Institute Canadian Institute for Health

25 manufacturers, plus 2 manufacturers’ organizations (NEMA - US, JIRA - Japan)

15 clinical user organizations (worldwide)

radiology, cardiology, pathology, dentistry, opthamology, dermatology, gastro-enterology

FDA Center for Devices and Radiological Health

National Cancer Institute

Canadian Institute for Health

Features of DICOM as a Medical Data Interchange Standard

Encoding Tagged, variable length data elements Tagging conceptually similar to XML (but tags are 32-bit binary, not variable length ASCII) Similar to TIFF Supports binary data values Encapsulated JPEG encoded pixel data Supports hierarchical data organization Extensible with private data elements

Tagged, variable length data elements

Tagging conceptually similar to XML (but tags are 32-bit binary, not variable length ASCII)

Similar to TIFF

Supports binary data values

Encapsulated JPEG encoded pixel data

Supports hierarchical data organization

Extensible with private data elements

Object Orientation Fundamental unit of interchange is an information object Instance Each Instance has a globally Unique ID Registered under the rules of ISO 9834-3 Information object classes defined for each clinical data acquisition modality (CT, MR, etc.)

Fundamental unit of interchange is an information object Instance

Each Instance has a globally Unique ID

Registered under the rules of ISO 9834-3

Information object classes defined for each clinical data acquisition modality (CT, MR, etc.)

Data Sets Sets of object Instances are organized by patient, study, and series virtual hierarchical folders Object Instances carry their full contextual identification (patient, order, study, procedure step, series) pargmatically more effective than separate objects managing each context level

Sets of object Instances are organized by patient, study, and series

virtual hierarchical folders

Object Instances carry their full contextual identification (patient, order, study, procedure step, series)

pargmatically more effective than separate objects managing each context level

Network Services Network Object Instance transfer Departmental workflow management (orders, status) Robust object management Object storage Query and Retrieve Media-based Object Instance file transfer CD-R, DVD, MOD DICOM MIME type for email attachment

Network Object Instance transfer

Departmental workflow management (orders, status)

Robust object management

Object storage Query and Retrieve

Media-based Object Instance file transfer

CD-R, DVD, MOD

DICOM MIME type for email attachment

Privacy and Security DICOM network communications may use SSL/TLS for node identification and/or transport encryption DICOM files (on media-based interchange) may use CMS (RFC-2630) crypto wrapper Object de-identification profile now in ballot allows scrubbed identifiers to be encrypted within the object

DICOM network communications may use SSL/TLS for node identification and/or transport encryption

DICOM files (on media-based interchange) may use CMS (RFC-2630) crypto wrapper

Object de-identification profile now in ballot

allows scrubbed identifiers to be encrypted within the object

Clinical Trials DICOM WG18 (Clinical Trials) currently developing header and profile for DICOM objects submitted for clinical trials WG18 Secretariat is National Cancer Institute

DICOM WG18 (Clinical Trials) currently developing header and profile for DICOM objects submitted for clinical trials

WG18 Secretariat is National Cancer Institute

Structured Reporting Much of recent DICOM effort directed to structured documentation of analyses and measurements SR uses a hierarchical tree of structured content items, using DICOM object syntax Unambiguous documentation of meaning through text, categorical codes, numeric measurements, inter-item relationships Careful attention to clinical observation context Leverage use of external coded vocabularies / terminologies Robust references to spatial and temporal coordinates in DICOM object Instances Explicit chain of inference may be documented

Much of recent DICOM effort directed to structured documentation of analyses and measurements

SR uses a hierarchical tree of structured content items, using DICOM object syntax

Unambiguous documentation of meaning through text, categorical codes, numeric measurements, inter-item relationships

Careful attention to clinical observation context

Leverage use of external coded vocabularies / terminologies

Robust references to spatial and temporal coordinates in DICOM object Instances

Explicit chain of inference may be documented

SR Use Cases Radiology / Cardiology / Pathology reports Computer Aided Detection / Diagnosis Key Image Notes SR Object Instances are separate from the analyzed Object Instances A single SR may report across multiple referenced objects from multiple studies

Radiology / Cardiology / Pathology reports

Computer Aided Detection / Diagnosis

Key Image Notes

SR Object Instances are separate from the analyzed Object Instances

A single SR may report across multiple referenced objects from multiple studies

DICOM Waveform Standard

History Cardiology community engaged with DICOM since 1992 for information standardization in the catheterization lab X-ray Angiographic images Invasive hemodynamic and electrophysiological waveforms Waveform digital samples, not picture of a display Non-invasive waveforms (ECGs) a “free” subset Associated measurement reports

Cardiology community engaged with DICOM since 1992 for information standardization in the catheterization lab

X-ray Angiographic images

Invasive hemodynamic and electrophysiological waveforms

Waveform digital samples, not picture of a display

Non-invasive waveforms (ECGs) a “free” subset

Associated measurement reports

Waveform Object Definition Channel Definition harmonized with HL7 v.2.3 Channel Source may use SCP-ECG lead codes Equipment creates Standard DICOM Composite Object Model

Channel Definition harmonized with HL7 v.2.3

Channel Source may use SCP-ECG lead codes

Standard DICOM Composite Object Model

Annotation Annotations part of the data acquisition may be included in the Waveform Object Instance e.g., suppressed pacemaker spikes Other annotations may be included in a Structured Report Object Instance global or per-lead measurements interpretive statements Both methods allow full description of annotated region (temporal coordinates) by sample number, by time offset, or by absolute time Annotations may be free text, or coded terms

Annotations part of the data acquisition may be included in the Waveform Object Instance

e.g., suppressed pacemaker spikes

Other annotations may be included in a Structured Report Object Instance

global or per-lead measurements

interpretive statements

Both methods allow full description of annotated region (temporal coordinates)

by sample number, by time offset, or by absolute time

Annotations may be free text, or coded terms

Implementations DICOM Waveform objects are being used for cath lab invasive waveforms allows management of Waveform objects with same infrastructure as DICOM angiographic images Commercial software available provides transcoding of proprietary format waveforms to DICOM format Many public and commercial toolkits available for DICOM object formatting and communication

DICOM Waveform objects are being used for cath lab invasive waveforms

allows management of Waveform objects with same infrastructure as DICOM angiographic images

Commercial software available provides transcoding of proprietary format waveforms to DICOM format

Many public and commercial toolkits available for DICOM object formatting and communication

http://medical.nema.org/dicom.html http://www.dclunie.com/dicom-status/status.html