Sharing images and documents between Enterprise VNAs Using IEP and XDS standards. Dave Harvey MRCP FRCR Medical Connections Ltd

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1 Sharing images and documents between Enterprise VNAs Using IEP and XDS standards Dave Harvey MRCP FRCR Medical Connections Ltd

2 Declaration of Interest Medical Connections Ltd supplies software which is used by Sectra in the Image Exchange Portal (IEP)

3 Dimensions of image and document sharing Internal/External Structured/Unstructured Centralised/Distributed Document-based/Data-based Push/Pull/Integrated

4 Push vs. Integrated vs. Pull Pushed: Data is explicitly send to the chosen destination(s), based on local policies Integrated: Data is accessed directly from an (effectively) single system commonly via proprietary means Pulled: Data is sent by existing systems via a standard interfaces to systems which then make it generally available

5 Push sharing Data sent to known end-points (people) Like a dialled telephone call Needs a routing infrastructure Little need for consistency/standardisation beyond the need for the recipient to be able to interpret the data Minimal Information Governance (IG) Issues No data discovery for other sites Examples exist: IEP & ITK

6 Sharing via VNA Data is copied from multiple sources (PACS and others) into a shared database Data can be accessed using: Native interface of the VNA Export / Integration to other systems Data needs to be sufficiently described to be findable Local data can easily be found IG needs careful management, but it is not very different from internal systems

7 Sharing via Pull Data sent to standard storage systems Registries & Repositories Like publishing to a web site Needs a central storage and indexing infrastructure Great need for consistency & standardisation to enable data discovery Major advantage is ability to discover remote data Significant IG Issues, as eventual user is unknown Examples exist, based on the IHE XDS model

8 Image Exchange Portal (IEP) The Image Exchange Portal (IEP) is a web-based application that allows healthcare professionals to securely transfer patient images and reports from one hospital trust to another. Has links into PACS at source and destination Uses a web interface to direct images to be pulled from the source, processed to ensure compatibility and then sent into the destination system Successful system used in most UK hospitals.

9 The IHE XDS Profile Generic means of sharing clinical documents Part of ITI domain (not Radiology) Based on clinical and non-clinical standards: Transmission: http/https + SOAP Indexing: ebxml Documents: CDA v2 PDF etc.

10 IG Issues for Pull Access Wider access requires tighter general security Even with that how do we identify and authorise users? Do we know who they are? Do we know their role? Do we know if they have a legitimate relationship? Full audit logging is essential in addition to the above

11 XDS-I for documents Like XDS but based on DICOM Uses the same registry so has indexing Images themselves are not replicated They are retrieved directly from the source PACS / VNA Multiple retrieval mechanisms: Native DICOM WADO Web Services

12 Metadata Issues Do we have data for the correct patient? NHS Number vs. Local MRN Metadata What data goes where in the index fields Author / Speciality Type of document etc. Consistent use of code sets (e.g. SNOMED)

13 The other aspects of security? Authenticity Is the data genuine? Availability System down time How complete is the data we have? Do we know what we don t have? How accurate are the searches?

14 Are we ready for Pull Technical standards exist Metadata standardisation is underway Re-use of existing sharing facilities (IEP & VNA) can provide useful technical assistance But will the IG barrier be surmountable?

15 Speed Issues Local will normally be faster Push and local VNA have an advantage Pull is likely to be slow for images Mitigation: Progressive image delivery Caching after first use Intelligent DICOM / other image formats Import into PACS?

16 Conclusion Push has its uses, and has worked well Pull is potentially more useful, but still has many barriers Consistent indexing Speed and associated image content IG!!!!