ihe profiles for enhanced dicom (ct and mr) kees verduin philips healthcare chair dicom wg16

IHE Profiles for Enhanced DICOM (CT

and MR)Kees Verduin

Philips HealthcareChair DICOM WG16

IHE Webinar Series 2009 2

Introduction

• DICOM has standardized the ENHANCED MR IOD in 2002 followed by CT in 2004 and others

• Modalities have already implemented these from the start, but workstations that support these are still scarcely available.

• To close the radiology cycle around these IHE makes choices that reduce the diversity of solutions and herewith guarantees interoperability for specific use cases.

• This will improve the acceptance of Enhanced SOP Classes by industry and users.


Summary

• IHE decided for development year 2008-2009 to work on 2 (out of 5) use cases prepared for MR and CT, 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 can not be done with Classic DICOM.

• The use cases will cover 80-90% of the routine applications in their area, suited for standard display systems.

• Both profiles that use the DIMENSION information, will be available for Trial Testing at the 2010 Connectathon in Chicago.

• This will make these cases also a baseline for other profiles for other DICOM Enhanced SOP Classes.


Agenda for this session

• 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

Common features for both profiles

Dimension Module:

Dimension Index Sequence is mandatory for IHE profiles


time

Temporal Position Index (Phase-index)

65

43

21

65

43

21

1 2 3

65

43

21

In-stack PositionNumber (Slice-Index) Frame number 1-6 Frame number 7-12Frame number 13-18

Multi-phase / Multi-Slice

Slice Order for phase 1

Phase order for slice 2

Image frames can be sorted/displayed independent of the frame order

4\1 4\2 4\3



Dimension Module

• There is a place where the dimension attributes are listed (these are existing 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)

• Frames shall be displayed according these indices (irrespective of the physical order of the frames in the object !!!)


Contrast Perfusion in CT/MR

• The CT/MR Perfusion Imaging with Contrast Integration Profile facilitates the exchange of contrast enhanced images containing standard attributes for timing and position.

• The exchange of these attributes allows for correct and convenient display.

• Applications using the older single-frame DICOM image objects, depend on proprietary assumptions about timing attributes expected to be present, and are not generally interoperable.


Use Case Description

• This use case refers to CT/MR Perfusion imaging that basically creates a stack of images at different timeslots, in order to demonstrate the (possibly selective) uptake of a contrast agent over time.

• The images shall be stored with indices along their position in the stack and the progress of time.

• The use case assumes that all these images are present as frames in one Enhanced CT object or one Enhanced MR object.

• Time and In-stack position are also to be stored as DIMENSION attributes


Requirements for creators

1. One Enhanced SOP Instance

2. Creator provides dimension indices for:• Stack ID• In Stack Position Number• Temporal Position Index

3. Data requirements:Image Type and Frame Type:

• Value 1: ORIGINAL• Value 2: PRIMARY• Value 3: PERFUSION


time

Temporal position Index (phase-index)

65

43

21

65

43

21

1 2 3

65

43

21

In-stack PositionNumber (Slice-index) Frame number 1-6 Frame number 7-12Frame number 13-18

Multi-phase / Multi-Slice


Phase order for slice 2

Image frames can be sorted/displayed independent of the frame order


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 In-Stack Position Numbers= simultaneous scrolling)

2. Be able to scroll the images by Temporal Position Index (phase-index = time related movie).

3. Be able to provide the time since the start (deducted from Frame Reference DateTime (0018,9151))


Position = 1 Position = 2 Position = .. Position = n

Time = 1

Time = 2

Time = ..

Time = n

Suggested display layout for use case support

scroll


Time = 1 Time = 2 Time = .. Time = n

Position = 1

Position = 2

Position = ..

Position = n

Suggested display layout for alternative use case support

scroll


Data Requirements for Display

• Display the values of the dimension attributes and contrast attributes.

• Display Frame annotations for Frame Number, Slice offset, relative time.


Diffusion in Brain

• This use case refers 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.

• The use case supports the presence of images created with post-processing

• The exchange of the selected attributes allows for correct and convenient display.

• Applications using the older single-frame DICOM image objects depended on proprietary attributes only, because diffusion parameters were not standardized.


Functional Requirements for Creators

• The images are stored in different Enhanced MR SOP Instances:1. a series of original images with different Diffusion b-

values. There shall be a stack of images 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 with resulting ISOTROPIC images (at least for b=max).

3. a series with ADC images for each slice (at least for b=max).

• The isotropic images and ADC images for b = max shall be presented in conjunction with the b=0 images for each slice.

• Note: This use case defines that non-isotropic images (which only differ by Gradient Direction) may be present, but are not of interest for standard viewing applications (these images may be specific for Diffusion postprocessing like FiberTracking).


SOP Instance Content

b=0

bx>0, direction 1, slice y

bx>0, direction .., slice y

bx>0, direction n………….……………………………

ISOTROPIC

ADC

SOP 1ORIGINALx b-values, y slices + n directionals

SOP 2DERIVEDx-1 b-values, y slices

SOP 3DERIVEDx-1 b-values, y slices


Image Type (and Frame Type) Values for the images in this use case

content b=0series

Isotropic series

ADCseries

Value 1 ORIGINAL DERIVED DERIVED

Value 3 DIFFUSION DIFFUSION DIFFUSION

Value 4 - ISOTROPIC ADC


Data Requirements for Creators

Creator provides dimension indices for:1. Stack ID

2. In Stack Position Number

3. Diffusion b-value (new IHE Use Case Requirement: to sort on increasing value Therefore index values are to be given according increasing b-value)

• Correct relationship between the different SOP instances.


Object Relations

• 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

• Source Image Sequence– Refers to the SOP Instance of the source images

• SOP Instance UID of the source


Functional Requirements for Display

1. Support by the display according the Image Dimensions.

2. Provide (at least) one row of three viewports for the display of frames for the same InStackPositionNumber (= slice number).

Minimally the frames with b=0 and an Isotropic for b=max and the ADC image for b=max should be displayed.

3. The frames for one InStackPositionNumber must be presented in one row.Additional rows can be used for other InStackPositionNumber-s.

4. Be able to filter (select) frames based on Diffusion Directionality attribute as described in the profile.

5. Be able to scroll the images (vertically) by InStackPositionNumber-Index.


b=0

ISO

ADC

Display ExampleSeriesnavigation

scro

ll

b=0Slice 1

b=0,Slice 3

b=0Slice 2

b=max ISOSlice 1

b=max ISOSlice 3

b=max ISO Slice 2

ADC for b=maxSlice 1

ADC for b=maxSlice 3

ADC for b=max Slice 2

Linked by position Linked by position

Thank You

Any Questions?

ihe profiles for enhanced dicom (ct and mr) kees verduin philips healthcare chair dicom wg16

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