Rad Tech Minutes 2009.01.27-30

Minutes

1. HL7 2.5 Refactoring

2. Joint ITI/WG 26 DICOM Webservices Review and Discussion

• Radiology presented an update on its current relevant activities and its use cases for image sharing

• Currently revising XDS-I profile to use XDS.b only
• Tracking progress of supplemental profiles in ITI needed to support Web services model--such as XUA for role-based access control--but not currently confident that these solutions are ready for implementation

• Radiology Use Cases for Image Sharing

• Access to prior images and reports
• Access to diagnostic images and reports for referring physicians
• Point-to-point transfer of images and reports from site to site or from a site to an outside provider of longitudinal patient record, such as a Personal Health Record system vendor

• Remote reading model employed frequently requires access by radiologist to multiple image sources

• Moving Radiology to shared model of ITI XDS for Web services

• Retrieve Transactions: Radiology should replace DICOM/Wado transport mechanisms with Web Services image retrieve transaction as compatible as possible with document retrieve method in XDS.b

• DICOM WG27 will help with specification of those transactions; ITI needs to coordinate with DWG27 to review divergences between the transactions defined for radiology and the general XDS retrieve model (retrieve document set)
• Need to consider responsiveness needs of the use case (synch/asynch; pipeline/non-pipeline queries and responses)
• DICOM WG27 needs to review "Appendix V" being developed by ITI to make sure that the Web services profiled "fit" imaging model; perform "gap" analysis and provide feedback to ITI
• Timing issue: need to have transactions specified before issuing XDS.b; standards would have to be specified by August 2009 in order to be implemented in 2009-2010 IHE Rad development cycle
• Should DICOM WG 27 own this activity or ITI? Need a teleconference to settle ownership

• Same model likely to be used for inter- and intraenterprise access

• Intra model has higher performance requirements
• Intra model has more precise query requirements

• Query Issues
• Can Radiology simplify the "three-layer" model of XDS-I: query to registry/reference to repository (with manifest only)/image source by enabling storage of images themselves in the repository layer
• Need new queries based on Web services (using their query engine) to address specific issues of discovering and retrieving imaging studies: DICOM WG 20 is working on new query standards

• Images need to be indexed (via manifest) so that large studies don't appear as multiple query entries
• XDS-I adds two query keys to basic XDS: body part and procedure code
• Manifest provides useful information about imaging study
• Currently not all general query keys are included in the radiology manifest to fit into optimized XDS.b model
• Extend in conformance with pattern for extensions developed by ITI
• Event code is expandable attribute/value list that could be used for Radiology specific keys (body part, procedure code); IHE Rad will propose list of extensions to ITI
• CP 228 in ITI that specifies "and/or" requirement for query response

• Point-to-point push of images/reports

• Does XDR enable pushing large image studies site to site (adheres to "provide and register" model)

• Push manifest and require receiver to retrieve
• Could include images (mime type) in provide and register transaction (convert DICOM metadata into XDS metadata)

• Distributed updates and image management functions (change in reason for study, etc)

• Metadata versioning profile in ITI allows you to inform registry
• Under Pub/Sub If new payload is sent, it is designated as a replace transaction

• Security mechanisms: role-based access control and authentication

• Notification

Radiology Technical Committee

• Expanding beyond the Affinity Domain model