General_Overview_by Andrei_Leontiev.ppt
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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...