DICOM INTERNATIONAL DICOM INTERNATIONAL CONFERENCE & SEMINAR April 8-10, 2008 Chengdu, China 1 Enhanced MR addresses Multi-Vendor interoperability issues in clinical radiology Kees Verduin, WG16-MR Philips Healthcare

2 Problem Statement Multi Dimensional datasets create problems in a multi-vendor environment.

3 Content 1.Enhanced MR Features /Benefits 2.Multi–dimension storage 3.From Chaos to Structure 4.Dimension Module 5.Clinical examples 6.Implementation scenarios 7.Conclusion

4 A new Standard, since 2003 Enhanced DICOM (e.g. for MR,CT,XA,PET,..) with Dimension Module

5 Spectroscopy Multi-stack Palette Color Dimension Module Multi-frame Real World Values Raw Data Enhanced MR Features

6 Enhanced MR Benefits 1.Transport Performance through new Multi-Frame concept 2.Better scan information new attributes for new scan techniques 3.Better Interoperability through more strict attribute rules 4.Context Information 1.Dimension Module 2.From “chaos” to “structure”

7 Enhanced MR Benefits Transport Performance –through new Multi-Frame concept Better scan information –new attributes for new scan techniques Better Interoperability –through more strict attribute rules Context Information –Dimension Module –From “chaos” to “structure”

8 Total body Imaging

This is how these images were scanned !

This is how these images were scanned !

This is how these images were scanned !

This is how these images were scanned !

This is how these images were scanned !

14 This is how these images must be displayed ! 1

15 This is how these images must be displayed ! 2

16 This is how these images must be displayed ! 3

17 This is how these images must be displayed ! 4

18 This is how these images must be displayed ! 5

19 Total Body Imaging display

20 How to store the images ? for easy retrieval for consistent display for optimal interpretation of parameters

21 Where to find the relevant data ? DICOM images are sent as separate objects. The relationship between the objects must be searched in Series attributes in these objects: –Like : Series Number, Series Description, Protocol Name, Sequence Name. –Despite 25 years of Image Format standardization, useful values for these attributes are not standardized ! –It will not be easy, if not impossible, to solve this in a standard. Interpretation of image information is especially difficult when the objects are from different series. Also when the relevant attributes themselves do not exist in the DICOM standard…. (private attributes like “number of.. “!)

22 Before “Enhanced MR” there was no standard way to solve this. Now Enhanced DICOM for MR (and also for CT/XA/RF/PET etc..) can structure a dataset by: –packaging all images in one object and –using specific and better standardized attributes for the organization. The Dimension Module can disclose the organization of the dataset to the receiving application. From “Chaos” to “Structure”

23 Where is the structure needed ? In fact, this affects ALL Workstation SW implementations ! Note: in this presentation most examples are from MR, but similar problems exist for other modalities.

24 What should be done ? 1.There was a problem for (MR) users in a multi-vendor environment. 2.This was specifically a dimension problem, that has increased in importance over time. 3.Since 5 years there is already a solution ! 4.This is only slowly adopted by workstations and PACS vendors. 5.Users should update their workstations and PACS systems to support Enhanced DICOM.

25 MR creates, conceptually, a Multi-Dimensional Image dataset Position (1-1000) Image type (1-3) Echo (1-20) Any parameter (x) Time ( ) Combinations of changing parameters create a whole space of images, which is defined by different dimensions. Diffusion b-Value (3-10) (Typical numbers)

26 There is an endless number of combinations and more …. Multi-Direction Diffusion scans –changing Diffusion gradient directions Multi-Slice Dynamic scans –changing anatomic position Multi-Slice Perfusion scans –changing contrast over time Multi-Slice Cardiac imaging –synchronized with the heart phase Multi-Slice + Multi-Echo scans Multi-Slice EPI (Echo Planar Imaging) scans And more …

27 MR creates, conceptually, a Multi-Dimensional Image dataset MR Scanners and MR Workstations from single vendors have dealt with this, in the classic DICOM MR Images. The penalty was: –the use of private attributes for identification and –vendors using different strategies for separating images into separate series.

28 Why was this not so much a problem in the past? Most users had scanners and workstations from one vendor. The storage choices were known by their own workstation SW Engineers. The third-party workstation vendors had to reverse-engineer the separation strategies.

29 More and more hospitals are merging into bigger Healthcare Enterprises. Users have more scanners and workstations from different vendors. New Independent Workstations New Independent PACS systems Increasing importance due to larger Enterprises

30 Multiple images of the same slice, most likely in different series. This leads to display problems for reading radiologists: –How can I see the values of the parameters that make the images different ? –How does my workstation organize the images that belong together ? –Why is it different for every scanner vendor ?

31 Enhanced DICOM, MultiFrame with Dimension Modules All images are stored as “frames” in one image object. Attributes may change from frame to frame. Attributes that are important for the display order of the frames, will be structured in the Dimension Module by the creator. This provides an explicit display scenario for the frames in the Enhanced (MR) object. This scenario can be used by viewing systems, even without specific (MR) application knowledge. It is vendor independent.

32 time Clinical example: Perfusion One slice at many time points

33 time Signal Clinical example: Perfusion One slice at many time points

34 Multi dimensional datasets Organization Attributes Example : Multi-slice –Multi-time acquisitions: Every Frame has: –a slice order attribute value (“In-Stack Position Number”) and a time order attribute value (“Trigger Delay Time”). These attributes are used as index in the Dimension Module. The Dimension Module gives herewith the default display order

35 Time In-Stack Position Number One Enhanced MR Image object

36 Enhanced MR, supports the Multi-Dimension structure All images stay together in one object. The Dimension Module describes all relevant dimensions and indicates the priority for the display order. A dedicated workstation may deviate from the suggested image ordering, by moving lower ranked dimensions upwards.

37 Total body Imaging requires Dimension Attributes Use ‘Stack-ID’ and ‘In-Stack Position Number’ for correct display

38 Other Examples: Diffusion Imaging “Diffusion b-values” from 0 to 8000 and an ADC image

39 Other Examples: Cardiac Cine Loops Enables automatic multi-slice / multi-phase display, even for standard workstations

40 Implementation Roadmap What if not all your systems are ready for Enhanced DICOM ?

41 MR Archive Workstation Negotiate The Negotiation scenario MR decides to send Enhanced object MR decides to send the Classic MR object PACS can not send and must cancel ! Negotiate Conclusion: One can not configure a PACS for Enhanced MR, as long as it is not supported in the diagnostic workflow.

42 MR Archive Workstation Negotiate Back to Square one ? Conclusion: No support for Enhanced MR (and “chaos” continues) MR decides to send the Classic MR object PACS decides to send the Classic MR object

43 MR Archive Workstation Negotiate Action required: Adapt the workstations ! MR decides to send Enhanced object PACS can not send and must cancel ! MR decides to send the Classic MR object Negotiate Action: Replace the blocking (part of the) Workstations PACS decides to send Enhanced object !

44 Conclusions All Workstations and all Image Managers should support and use Enhanced DICOM SOP Classes with the Dimension Module. –Enhanced (MR) objects exist worldwide. >1600 MR systems are waiting to send their data. Only then, the clinical users can benefit from the other features of Enhanced Objects

45 Summary Enhanced DICOM solves Multi Vendor Dimension problems. Workstation and PACS vendors must implement this. Hospitals must invest in upgrades to fully benefit.

46 Further Information ? See: Henri Matthijssen with his poster about the Philips Implementation of Enhanced MR