Transcript x-1 - IHE.net

North American 2010
IHE Webinar Series
Radiology Update:
IHE Profiles for Enhanced
DICOM (CT and MR)
Kees Verduin
Philips Healthcare
Chair DICOM WG16
Introduction
• DICOM has standardized the ENHANCED MR IOD in
2002, followed by CT in 2004 and later for others.
• Some modality vendors have already implemented
these IODs, but workstations that support these are
still scarcely available.
• To support the radiology workflow, IHE makes
choices to provide a common place for solutions and
herewith guarantees interoperability for specific use
cases.
• This will also improve the acceptance of Enhanced
SOP Classes by industry and users.
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Agenda for this session
• Benefits of Enhanced DICOM
• Common features for both profiles
–
Dimension Module Concept
• Contrast Perfusion in CT/MR
–
–
–
Use case
Object Requirements
• Restrictions for Modalities, additional requirements
Display requirements
• Diffusion in MR
–
–
–
Use case
Object Requirements
• Restrictions for Modalities, additional requirements
Display requirements
• Summary
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Benefits of Enhanced DICOM
• Modern Acquisition Techniques are fully covered.
(no longer dependent on private attributes)
• Multi-frame packaging for fast transfer.
(only one file to transfer)
• Explicit Dimensions.
(this provides context information, especially
useful for standard display systems)
• Implementing Enhanced DICOM for one modality
will pave the way for all other implementations.
(most constructions are identical).
3
Common features for both profiles
• Enhanced DICOM SOP Classes only
• Dimension Module:
– Dimension Index Sequence is mandatory for
the IHE profiles
4
Multi-phase / Multi-Slice
time
Temporal Position Index (Phase-index)
Dimension index values:
1
Slice Order
for phase 1
6
4\1
5
In-stack 4
Position
3
2
Number
1
(SliceFrame number 1-6
Index)
4\2
2
Slice Order
for phase 2
6
5
4\3
3
6
4
3
2
5
1
Frame number 13-18
4
3
Phase order for
slice 2
2
1
Frame number 7-12
Image frames can be sorted/displayed independent of the frame order
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5
DICOM Dimension Module
• There is a place where the dimension attributes are
listed through their tag-number (these are the
attributes, that play a role in the object dimension,
like : time, position, echo, phase, contrast, …….) :
>Dimension Index Pointer (0020,9165)
• There is a place where for each frame the index
values for these attributes are stored:
>Dimension Index Values (0020,9157)
See notes
See notes
• Frames shall be displayed according these indices (irrespective
of the physical order of the frames in the object !!!).
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IHE Profile PERF
Contrast Perfusion in CT/MR
Contrast Perfusion in CT/MR
• This Integration Profile facilitates the exchange of
contrast enhanced images created as
a stack of images at different timeslots, in order to
demonstrate the uptake of a contrast agent over time.
• The exchange of standard attributes for time and position
allows for correct and convenient display
on standard display systems.
• This is a major improvement compared to the older
single-frame DICOM image objects (where applications
depend on proprietary assumptions about the presence of
certain timing attributes)
The new image objects are generally interoperable.
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MR Perfusion Imaging
time
Stor
ed
valu
es
Real World
Value Slope
(0040,9225)
non perfused
stroke area
Signal
Real World
Value Intercept
(0040,9224)
RW
values
delayed perfusion
time-to-peak map
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Requirements for creators
1.
One Enhanced SOP Instance (CT / MR)
2.
Creator provides dimension indices for:
•
•
•
3.
Stack ID
In Stack Position Number
Temporal Position Index
Data requirements:
Image Type and Frame Type:
•
•
•
Value 1: ORIGINAL
Value 2: PRIMARY
Value 3: PERFUSION
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Functional Requirements for Image Display
1.
Provide at least one viewport for display of frames with
the same In-Stack Position Number (Slice-index).
(More viewports may be used for displaying images for other InStack Position Numbers= simultaneous scrolling)
2.
Be able to scroll the images by Temporal Position
Index (phase-index = time related movie).
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Suggested display layout
Position = 1
Position = 2
Position = ..
Position = n
scroll
Time = 1
Time = 2
Time = ..
Time = n
Alternative display, through switching Position and Time
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Data Requirements for Display
•
Display the values of the dimension attributes and
contrast attributes and Frame Type value 3.
•
Possible display annotations for Frame Number,
relative frame time, etc.
Note:
Given the start time of the scan (Acquisition DateTime (0008,002A)), the
relative frame time can be calculated through its subtraction from each
Frame Reference DateTime (0018,9151).
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IHE Profile DIFF
Diffusion in the Brain
Diffusion in the Brain
• The use case supports the MR procedure of standard
Diffusion Weighted Imaging (DWI) or Diffusion Tensor
Imaging (DTI), in which stacks of images (slices) are
generated with different meaning and derived contrast.
• A number of these images created by post-processing.
• The exchange of the selected attributes allows for
correct and convenient display on standard display
systems.
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Diffusion Transaction Diagram
Evidence Creator
 RAD-10: Storage Commitment
Image
Manager
 RAD-10: Storage Commitment
Image Display
RAD-18: Creator Images
Stored 
 RAD-14: Query Images
 RAD-16: Retrieve Images
Image
Archive
RAD-8: Modality Images
Stored

Acquisition Modality
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Functional Requirements for Creators
•
The images shall be stored in three different
Enhanced MR SOP Instances:
1. a series of ORIGINAL images for different Diffusion bvalues for each slice (at least for b=0).
For other b-values there may be images for different diffusion gradient
directions, but these are not to be displayed (see note).
2. a series of DERIVED ISOTROPIC images for each slice
(at least for b=max).
3. a series of DERIVED ADC images for each slice
(at least for b=max).
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DIFFUSION MR SOP Instance Content
SOP 1
SOP 2
SOP 3
b=0 , slice y
bx>0, direction 1, slice y
bx>0, direction .., slice y
bx>0, direction n………….
……………………………
ORIGINAL
x b-values, y slices +
(x-1)*y*n DIRECTIONAL images
ISOTROPIC, b=max, slice y
DERIVED
ISOTROPIC
x-1 b-values, y slices
ADC, b=max, slice y
DERIVED
ADC
x-1 b-values, y slices
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Example of Diffusion Images
“Diffusion b-values” from 0 to 8000 and an ADC image
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Display Example
Series
navigation
Linked by position
Linked by position
b=0
ISO
scroll
ADC
b=0
Slice 1
ISO for b=max
Slice 1
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ADC for b=max
Slice 1
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Data Requirements for Creators
•
Creator provides dimension indices for:
1.
2.
3.
Stack ID
In Stack Position Number
Diffusion b-value
•
Additional IHE Use Case Requirement:
to assign the Diffusion b-value index according the
increasing b-value.
•
Correct relationship between the different SOP
instances through Source- and Derivation Sequences.
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DICOM Object Relations
• Source Image Sequence
– Refers to the SOP Instance
of the source images
• Derivation Image Sequence
– Refers to the method used for derivation.
• Codes to be used for Image Derivation: CID 7203
– Isotropic: Diffusion weighted : 113043
– ADC: Apparent Diffusion Coefficient: 113041
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Functional Requirements for Display
1.
Support DICOM Image Dimensions.
2.
Provide (at least) one row of three viewports to display
frames with the same InStackPositionNumber-Index (=
slice number).
3.
Displayed alongside for each slice:
1.
2.
3.
4.
the original image for b=0,
the ISOTROPIC image for b=max,
the ADC image for b=max.
Be able to scroll the images (linked) by
InStackPositionNumber-Index (=slice)
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Display Example
Series
navigation
Linked by position
Linked by position
b=0
b=0
Slice 1
ISO
ISOTROPIC
for b=max
Slice 1
scroll
ADC
b=0
Slice 2
ISO for b=max
b=0,
Slice 3
ISO for b=max
Slice 2
Slice 3
IHE Webinar Series 2009
ADC
for b=max
Slice 1
ADC for b=max
Slice 2
ADC for b=max
Slice 3
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Data Requirements for Display
•
Display the values of the dimension attributes
•
Possible display annotations for Frame Number,
relative position , etc.
Note:
Given the values for Image Position Patient, it should be possible to
calculate the relative distance for each slice from a reference slice (e.g.
from the first slice in the stack.
The profile text requires this to be displayed in mm.
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Summary
Summary
• IHE developed Integration profiles to enable testing of
existing and future implementations of Enhanced DICOM
SOP Classes.
• The selection was made for:
– CT/MR Perfusion: “PERF”
because the timing attributes are better defined in Enhanced
DICOM IODs.
– MR Diffusion: “DIFF”
because this cannot be done with Classic DICOM.
• Both profiles use the DIMENSION information.
• Use of these profiles will facilitate the display of the more
complex acquisitions on standard display systems.
• The profiles will be available for Trial Testing at the 2010
Connectathons to prove their interoperability.
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Thank You
Any Questions?