Transcript General_Overview_by Andrei_Leontiev.ppt

DICOM 2001:
the old, the new and the future
Andrei Leontiev
Chairman, Working Group 6
IDX Systems Corporation
DICOM 2001 Vital Statistics
 9 new Supplements
 41 Correction Items
 New Part 16 “Content Mapping Resource”
 And as of end of 2001, Final Text of
DICOM is available for download free of
charge from DICOM web-site:
– http://medical.nema.org
Major focus of DICOM in 2001
 Security
– Digital Signatures, Media
 Applications of structured reporting
(DICOM SR):
– Mammography CAD
– Key Object Selection Documents
 Workflow
– General Purpose Worklist
Major focus of DICOM in 2001
 New Media
– DVD-RAM, E-mail attachments, large capacity
MODs
 New Objects
– Enhanced Secondary Capture
– IVUS
 JPEG 2000 (Approved early 2002)
 Standard Maintenance
Security - Digital Signatures
 Authentication
– verifying the identity of entities involved in an
operation
 Data Integrity
– verifying that data within an object has not been
altered or removed
Security - Authentication
 Added Attributes to Information Object
Definitions that allow creators or modifiers
of SOP Instances to certify their identity
through Digital Signatures.
 This authentication is in addition to any
authentication done when exchanging
messages over a Secure Transport
Connection.
Security - Data Integrity
 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
 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
 Introduces Concept of DICOM Secure File
– Utilizes Cryptographic Message Syntax
– Encapsulates DICOM Content in the secure
envelope
– Industry standard Triple-DES encryption
 New DICOM Media Storage Security
Profile
Content Mapping Resource
 Major step to make SR work
 Defines and maintains DICOM Context
groups - semantically-related collections of
terms from SNOMED, LOINC, SCPECG,
BI-RADS, UCUM
 Defines and maintains DICOM-specific set
of terms, as well as their translations:
– French, Japanese...
Agreement with SNOMED
 DICOM used some SNOMED terms in pre-
2001 editions
 License is needed for use of SNOMED
 DICOM and SNOMED agreed that x terms
are available to DICOM users on the
royalty-prepaid basis.
Mammography CAD
 First SR-based specialized SOP class.
 Extensive use of templates.
 Separation into a SOP Class allows for
precise control of the document’s structure
 Introduced several templates that are being
utilized by other SR-based SOP Classes
– Measurements
– Image library
Key Object Selectors
 Simplified Basic Text SR-based SOP Class
to convey selection of a number of
composite instances for certain purpose
 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
 Document Titles:
– For Conference
– For Patient
– For Referring Provider
– Quality issues
– etc.
 Used in IHE key Image Note Integration
Profile
General Purpose Worklist
 Major step to better workflow solutions in
reporting (interpretation, transcription),
post-processing, CAD, RT, Print, …
 Builds on the experience with Modality
Worklist and MPPS
 Utilizes concepts of Scheduled and
Performed Procedure Steps
 Unlike in Modality Worklist, the SPS is a
manageable Normalized object
General Purpose Worklist
 SCU can request the
SCHEDULED
SUSPENDED
COMPLETED
SCU action
SCP action
IN PROGRESS
DISCONTINUED
SPS state change but
SCP ultimately
manages SPS states
 SCU retrieves SPS
info using C-FIND
 SCU requests SPS
state change using NACTION
 SPS Locking
General Purpose Worklist
 GP-PPS is managed similarly to MPPS (N-
CREATE, N-SET, N-GET), with InProgress, Completed and Discontinued
states
 Meta SOP Class of Worklist, GP-SPS and
GP-PPS is defined.
 There is a defined relationship between GPSPS and GP-PPS
General Purpose Worklist
Acquisition
Modality
Archive
Workflow
Manager
Performing
Device
Acquisition Complete
Schedule Interpretation
Store SOP Instances
Query GP-SPS
Receive GP-SPS
Transmit SOP
Instances for Input
Information
Update GP-SPS (IN PROGRESS)
Create GP-PPS (IN PROGRESS)
PROGRESSPROGRESS)
Set GP-PPS (COMPLETED)
Update GP-SPS (COMPLETED)
Store Results
New and Improved SC
 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
 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
 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
 Specifies SCP display/rendering
conformance in more rigorous manner
New and Improved SC
 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
 IVUS acquisition is part of cardiac
catheterization and peripheral vascular
medical imaging.
 Utilizes existing US image infrastructure,
adds module for time synchronization
 Simultaneous acquisition of images and
waveforms (audio and/or ECG).
 Images and waveforms are carried in separate
SOP Instances, with cross-references
New supplements in the works
 New Multi-Frame MR and CT objects
 New SR-based objects:
– Chest CAD
– Cath Lab
– Ultrasound measurements
– Echocardiography
– Vascular ultrasound
 Configuration Management
New Transfer Syntaxes & Media
 New content (SR) requires different
compression algorithms - Internet-standard
“deflate” (zlib) transfer Syntax is added for
SR Objects.
 Many old JPEG syntaxes have never been
used; retired but 4 of old JPEG syntaxes
 Added JPEG 2000 (Jan 2002).
New Transfer Syntaxes & Media
 New Media Technologies and requirements
of applications prompting support for largecapacity media:
– DVD-RAM
– 640 MB, 1.3, 4.1 GB MODs
 Internet e-mail is profiled like media (files
and filesets)
 DICOM MIME type (application/dicom) is
registered with IETF
DICOM and other standards
 Joint Working group (WG20) with HL7
(Imaging Integration SIG), works on
harmonization of DICOM and RIM,
templates, etc.
 Agreement between DICOM and SNOMED
 WG10 works with ISO TC215 WG2
 Liaison with JPEG
Conclusion
 16 parts of official DICOM 2001 edition
are available at http://medical.nema.com
 Since publication of DICOM 2001, 5 more
supplements have been finalized
 More to come...