# Presentation: 098161

## 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**

## 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**

## 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**

## 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**

## 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**

## 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.)**

## 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**

## 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**

## 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**

## Clinical Trials

**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**

## 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**

## 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 **

## 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***

## 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**

## 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**

## http://medical.nema.org/dicom.html

**http://www.dclunie.com/dicom-status/status.html**