What’s New in DICOM
Harry Solomon, GE Healthcare
RSNA 2007
DICOM is the International Standard for
Medical Imaging and related information:
images, waveforms, derived measurements
and assessments, image presentation control,
and workflow management for the imaging
department
Published as NEMA PS3 and as ISO 12052
What's new in DICOM - RSNA 2007
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Agenda
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The DICOM Change Process
Images
Image Processing & Reporting
Workflow
Specialties
Get Involved!
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The DICOM Change Process
• Continuous process for evolution of the standard
– It’s just “DICOM”, not DICOM 3.0, 3.1, etc.
– Conformance is to SOP Classes, not to a ‘version’ of the
Standard
• Change Proposals for minor corrections
– About 100 / year
– Anybody can submit
• Supplements for major changes – new object types,
services, compression schemes
– About 10 / year
– Require Work Item approved by DICOM Standards Committee
• Consolidated edition published every year
– Most recently, January 2007
– Available free at DICOM web site
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Images
Information Object Definitions
and Image Access
Multiframe Images
• Multiframe objects to support 1000+ slice studies
– Image header supports functional group attributes
changing during acquisition
– Dimensions allow multiple views of data
• Common structure used for all new image IODs
– Sup 110 Ophthalmic Coherence Tomography
(Adopted August 2007)
– Sup 116 3-D X-ray (Adopted January 2007)
– Sup 117 Enhanced PET (in Letter Ballot)
– Sup 43 Enhanced Ultrasound (in Public Comment)
– Sup 125 Breast Tomosynthesis (in Public Comment)
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Single-frame to MultiFrame
N Objects, N Headers
N Frames, One Header
Fixed Header
Per-frame header
What's new in DICOM - RSNA 2007
Dimension data
Pixel data
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The Per-Frame Header
Other attributes
Shared Functional Groups Sequence
> Functional Group A
…..
Functional Groups
with attributes constant
for all frames
> Functional Group K
Per-frame Functional Groups Sequence
Item 1 (Frame 1)
> Functional Group B
> Functional Group C
Sequence of
Functional Groups
for each individual frame
…..
> Functional Group M
Item 2 (Frame 2)
…..
> Functional Group B
> Functional Group C
…..
> Functional Group M
…..
Pixel Data
Frame 1
Item n (Frame n)
> Functional Group B
> Functional Group C
…..
> Functional Group M
Other attributes
What's new in DICOM - RSNA 2007
Frame 2
…..
Frame n
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Sup 119 Frame Level Retrieve
• If we have 1000+ slice image objects, how do we access
the slice identified in the report as the Key Image?
– Or, how to access a short video clip of a long endoscopy video
image object?
– Many similar use cases needing one frame or a small subset of
frames from large multiframe image
– Purpose of retrieval may not be diagnostic; compression OK
• Proposed new Retrieve SOP Classes for subsets of
frames
– Request can include a preferred transfer syntax (i.e., type of
compression)
– Returned object is a derived image with the requested subset of
frames, but with a different Instance UID
In Public Comment
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Sup 43 Enhanced Ultrasound
• Pixel frames may represent tissue, velocity, variance or power
• Multiple frames (up to 3) must be blended for proper display
• Enhanced blending pipeline required to render images
Real World
Value +Units
Real World Value
Mapping
Data Frame
Modality
LUT
(identity)
Gray Scale
Output as
P-Values
Presentation
LUT
(identity)
VOI LUT
(optional)
Convert to
RGB (R=B=G)
Primary
RGBA
Palette
Color LUT
RGB (Input 1)
RGB (Input 1)
(optional)
Alpha
OR
OR
Alpha, Beta
(Constants)
MSB’s
Blending
Operation
Opacity
LUT
(optional)
LSB’s
ICC Input Profile
Alpha 1
Alpha,
Beta
LUT
outputs
OR
Alpha 2
Multiply inputs and
add the result
(Alpha 1) x Input 1
+
(Alpha 2) x Input 2
RGB
C
L
A
M
P
RGB
Profile
Connection
Space
Transformation
RGB
Color Output
as
PCS-Values
(1-Alpha), Alpha
Alpha
Data Frame
Data Frame
Modality
LUT
(identity)
Modality
LUT
(identity)
VOI LUT
(optional)
VOI LUT
(optional)
Secondary
RGBA
Palette
Color LUT
RGB (Input 2)
(optional)
Real World Value
Mapping
Real World Value
Mapping
What's new in DICOM - RSNA 2007
Real World
Value +Units
In Public Comment
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Image Processing & Reporting
Segmentation, Registration,
Structured Reporting
Sup 111 Segmentation Image
• Derived image object
– Multiframe, using functional group mechanism
• Multiple segments per object
– Each segment linked to a categorization
– Pixels show presence of category at pixel location
– Binary (1-bit/pixel) or fractional (probability or occupancy)
• Segments can be 2-D or 3-D
• 3-D segmentation is typically in same Frame of
Reference as source image
• Segments can be displayed as overlays on source image
Adopted August 2006
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Segmentation Example
Binary Segmentation Results
Other attributes
White Matter
Segment 1
Segment Sequence
Item 1 (Segment 1)
Segment Number = 1
Segment Name = White Matter
Segment Category = Brain
Segment Type = White Matter
Item 2 (Segment 2)
Segment Number = 2
Segment Name = Grey Matter
Segment Category = Brain
Segment Type = Grey Matter
Item 3 (Segment 3)
Segment Number = 3
Segment Name = Lesion Part 1
Segment Category = Brain
Segment Type = Lesion
Item 4 (Segment 4)
Segment Number = 4
Segment Name = Lesion Part 2
Segment Category = Brain
Segment Type = Lesion
Gray Matter, CSF
and Partial Volume
Segment 2
Lesion – Part 2
Segment 4
2
Shared Functional Groups Sequence
Item 1 (Shared – all frames)
Derivation Image Sequence
Item 1
Reference to source
image (external object)
Lesion – Part 1
Segment 3 3
Per-frame Functional Groups Sequence
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Item 1 (Frame 1)
Segment Identification Sequence
Item 1
Referenced Segment
Number = 1
Item 2 (Frame 2)
Segment Identification Sequence
Item 1
Referenced Segment
Number = 2
Item 3 (Frame 3)
Segment Identification Sequence
Pixel Data
Frame 1
Item 1
Referenced Segment
Number = 3
Frame 2
Frame 3
Item 4 (Frame 4)
Segment Identification Sequence
Frame 4
Item 1
Referenced Segment
Number = 4
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Sup 132 Surface Segmentation
• Work in progress – just released for Public Comment
• Segmentation using 3-D surface mesh (rather than voxel
volume)
• First use of mesh technology in DICOM
– Will also be used for future volumetric work, including implant
specification and surgical planning
In Public Comment
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Sup 112
Deformable Spatial Registration
• Composite Object that supports multi-image alignment
• 3 step algorithm
– Pre-deformation matrix transform
– Deformation using 3D grid of 3D deformation vectors
– Post-deformation matrix transform
• Facilitates further image processing, especially multimodality image fusion and image pasting applications
Adopted August 2006
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Structured Reporting
• Additional Templates for standard SR SOP Classes
– Sup 128 Cardiac Stress Testing (Frozen Draft – passed
Ballot, awaiting final SNOMED and IEEE codes)
– Sup 129 Cardiac Electrophysiology (in Public Comment)
• Templates for specialty SR SOP Classes
– Sup 127 CT Radiation Dose (Adopted October 2007)
– Sup 130 Ophthalmic Refractive SR (in Letter Ballot)
– Sup 126 Colon CAD (in preparation)
• Harmonization with HL7
– Sup 114 DICOM Encapsulation of CDA Documents
(Adopted January 2007)
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Workflow
Substance Administration,
Unified Worklist, RT Workflow,
Specimen Identification
Sup 107 Substance Administration
• Patient safety issue – “five rights” checking for contrast agents
– Point of use verification for substances often “out of the loop” of
hospital pharmacy systems
• Three new DICOM services
– Typically Modality as SCU interacting with HIS via gateway SCP
• Query: Look up product characteristics
– Given a barcode ID (from contrast agent bottle), get name, active
ingredient, concentration, etc.
• Query: Get substance administration approval
– Based on agent, patient, route of administration; get approval or
warnings
• Report contrast used to HIS Medication Administration Record
Adopted January 2007
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Sup 96 Unified Procedure Steps
• Simplification and merger of Worklist Management and
Performed Procedure Steps
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–
–
–
–
–
1:1 relationship between scheduled and performed steps
A single IOD that combines attributes of both
C-FIND to query worklists
N-CREATE to create new scheduled procedure steps
N-GET/N-SET to update
N-EVENT-REPORT to monitor and report progress
• Intended to meet the needs of
– Radiation Therapy Scheduling and Monitoring
– Scheduling and Monitoring CAD systems
– Proposed new scheduling activities
Frozen Draft for Trial Implementation
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Sup 74 Radiotherapy Worklist
• Supports automated worklist management and machine
parameter verification for the integration of multisystem radiation therapy planning and treatment
• First usage of Unified Procedure Step
• Also defines three new objects / SOP Classes
– RT Beams Delivery Instruction (Composite)
– RT Conventional Machine Verification (Normalized)
– RT Ion Machine Verification (Normalized)
• Real implementation and evaluation needed – in
conjunction with IHE Radiation Oncology
Frozen Draft for Trial Implementation
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Sup 122 Specimen Identification
• Support for pathology lab workflow, specimen-based imaging
– Gross specimens, blocks, vials, slides
– Image-guided biopsy samples
• Retires current Specimen Identification Module, adds new
Specimen Module at image level of hierarchy
– May affect applications that implement current Module (if any)
• Update to Modality Worklist to allow Specimen Module
– Enables automated slide scanning devices to fully populate
header
• Update to Modality Performed Procedure Step to identify
imaged specimen
– Allows LIS to track images for specimens
In Public Comment
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Specialties
• Biomed engineering
– Supp 124 Communication of Display Parameters (in preparation)
– Administrative support for monitor calibration
• Research / Biomarkers
– Supp 118 Application Hosting (in preparation)
– Image analysis programs run on any workstation
• Surgery
– Sup 131 Implant Description (in preparation)
– Supports 3D model of bone-mountable implants
• Dentistry / Radiology
– Sup 123 Structured Display (in preparation)
– Captured screen layout of multiple images (with presentation
states) for dental series, radiology conference, etc.
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Get Involved!
• Get the DICOM Standard (free!)
– http://dicom.nema.org/medical/dicom/2007/ (annual issue)
– ftp://dicom.nema.org/medical/dicom/final (changes between issues)
• Ask questions/discuss on the DICOM Newsgroup
– http://groups.google.com/group/comp.protocols.dicom
• Respond to Supplements released for Public Comment
– http://www.dclunie.com/dicom-status/status.html
• Submit Change Proposals
– mailto:hclark@medicalimaging.org
• Join a DICOM Working Group
– See list in http://medical.nema.org/dicom/geninfo/Strategy.pdf
• Attend the DICOM International Conference and Seminar, Chengdu,
China, April 8-10, 2008
– http://dicom.nema.org/Dicom/DCS-2008/
• Build the new DICOM capabilities into your products
– Your URL here!
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