DICOM 2001: the old, the new and the future Andrei Leontiev Chairman, Working Group 6 IDX Systems Corporation

DICOM 2001 Vital Statistics 4 9 new Supplements 4 41 Correction Items 4 New Part 16 “Content Mapping Resource” 4 And as of end of 2001, Final Text of DICOM is available for download free of charge from DICOM web-site: –

Major focus of DICOM in Security –Digital Signatures, Media 4 Applications of structured reporting (DICOM SR): –Mammography CAD –Key Object Selection Documents 4 Workflow –General Purpose Worklist

Major focus of DICOM in New Media –DVD-RAM, attachments, large capacity MODs 4 New Objects –Enhanced Secondary Capture –IVUS 4 JPEG 2000 (Approved early 2002) 4 Standard Maintenance

Security - Digital Signatures 4 Authentication –verifying the identity of entities involved in an operation 4 Data Integrity –verifying that data within an object has not been altered or removed

Security - Authentication 4 Added Attributes to Information Object Definitions that allow creators or modifiers of SOP Instances to certify their identity through Digital Signatures. 4 This authentication is in addition to any authentication done when exchanging messages over a Secure Transport Connection.

Security - Data Integrity 4 New Security Profiles: –Secure Use Profiles: Basic Digital Signatures Bit-Preserving Digital Signatures –Digital Signature Profiles: Base RSA Creator RSA Authorization RSA

Security - Media Security 4 Addresses the following aspects of security at the level of DICOM media storage: –Data Confidentiality - assuring that information is not made available or disclosed to unauthorized individuals, entities or processes, –Data Integrity - assuring that data has not been altered or destroyed in an unauthorized manner, –Data Origin Authentication - the corroboration that the source of data received is as claimed

Security - Media Security 4 Introduces Concept of DICOM Secure File –Utilizes Cryptographic Message Syntax –Encapsulates DICOM Content in the secure envelope –Industry standard Triple-DES encryption 4 New DICOM Media Storage Security Profile

Content Mapping Resource 4 Major step to make SR work 4 Defines and maintains DICOM Context groups - semantically-related collections of terms from SNOMED, LOINC, SCPECG, BI-RADS, UCUM 4 Defines and maintains DICOM-specific set of terms, as well as their translations: –French, Japanese...

Agreement with SNOMED 4 DICOM used some SNOMED terms in pre editions 4 License is needed for use of SNOMED 4 DICOM and SNOMED agreed that x terms are available to DICOM users on the royalty-prepaid basis.

Mammography CAD 4 First SR-based specialized SOP class. 4 Extensive use of templates. 4 Separation into a SOP Class allows for precise control of the document’s structure 4 Introduced several templates that are being utilized by other SR-based SOP Classes –Measurements –Image library

Key Object Selectors 4 Simplified Basic Text SR-based SOP Class to convey selection of a number of composite instances for certain purpose 4 Uses single, non-extensible template: –Coded title that conveys purpose of selection, with possible modifier –Single textual content item with description –List of references to images, waveforms, etc.

Key Object Selectors 4 Document Titles: –For Conference –For Patient –For Referring Provider –Quality issues –etc. 4 Used in IHE key Image Note Integration Profile

General Purpose Worklist 4 Major step to better workflow solutions in reporting (interpretation, transcription), post-processing, CAD, RT, Print, … 4 Builds on the experience with Modality Worklist and MPPS 4 Utilizes concepts of Scheduled and Performed Procedure Steps 4 Unlike in Modality Worklist, the SPS is a manageable Normalized object

General Purpose Worklist 4 SCU can request the SPS state change but SCP ultimately manages SPS states 4 SCU retrieves SPS info using C-FIND 4 SCU requests SPS state change using N- ACTION 4 SPS Locking

General Purpose Worklist 4 GP-PPS is managed similarly to MPPS (N- CREATE, N-SET, N-GET), with In- Progress, Completed and Discontinued states 4 Meta SOP Class of Worklist, GP-SPS and GP-PPS is defined. 4 There is a defined relationship between GP- SPS and GP-PPS

General Purpose Worklist

New and Improved SC 4 The existing Secondary Capture object has: –no constraints on Photometric Interpretation –no constraints on bit depth –no compression transfer syntaxes very poor implementation support for 1 bit –no support for scanned document concepts –no multi-frame capability.

New and Improved SC 4 The effects of these limitations are that: –SC SOP Class "conformance" is too vague –No obvious way to determine support for: grayscale or color of some form typical 1 bit, 8 bits, 16 bits pixel matrix size (limits to 512, 1024, etc.) –Poor 1 bit support prevents use for scanned documents

New and Improved SC 4 A family of SC SOP Classes that supports: –1 bit MONOCHROME2 single component (0 is black, 1 is white) –8 bit unsigned grayscale MONOCHROME2 & VOI LUT to P-Values –9-16 bit unsigned grayscale MONOCHROME2 & VOI LUT to P-Values –8 bit per channel color-by-pixel RGB 4 Specifies SCP display/rendering conformance in more rigorous manner

New and Improved SC 4 Applications: –scanned documents 1 bit grayscale additional "page" descriptive attributes –frame grab acquisitions –screen shots from grayscale with windowing intact from true or indexed color –sets of synthesized images pan around 3D reconstructions (multi-frame movie)

IVUS 4 IVUS acquisition is part of cardiac catheterization and peripheral vascular medical imaging. 4 Utilizes existing US image infrastructure, adds module for time synchronization 4 Simultaneous acquisition of images and waveforms (audio and/or ECG). 4 Images and waveforms are carried in separate SOP Instances, with cross-references

New supplements in the works 4 New Multi-Frame MR and CT objects 4 New SR-based objects: –Chest CAD –Cath Lab –Ultrasound measurements –Echocardiography –Vascular ultrasound 4 Configuration Management

New Transfer Syntaxes & Media 4 New content (SR) requires different compression algorithms - Internet-standard “deflate” (zlib) transfer Syntax is added for SR Objects. 4 Many old JPEG syntaxes have never been used; retired but 4 of old JPEG syntaxes 4 Added JPEG 2000 (Jan 2002).

New Transfer Syntaxes & Media 4 New Media Technologies and requirements of applications prompting support for large- capacity media: –DVD-RAM –640 MB, 1.3, 4.1 GB MODs 4 Internet is profiled like media (files and filesets) 4 DICOM MIME type (application/dicom) is registered with IETF

DICOM and other standards 4 Joint Working group (WG20) with HL7 (Imaging Integration SIG), works on harmonization of DICOM and RIM, templates, etc. 4 Agreement between DICOM and SNOMED 4 WG10 works with ISO TC215 WG2 4 Liaison with JPEG

Conclusion 4 16 parts of official DICOM 2001 edition are available at 4 Since publication of DICOM 2001, 5 more supplements have been finalized 4 More to come...