Radiology Image Sharing Roadmap

<WARNING: Half-baked sketch follows>

Aspects of Image Sharing

Image Sharing should address Awareness, Selection and Access of image data.

There are different viable approaches to each of those three aspects of sharing.

Awareness

Knowing there are images that might be of use.

• Sink Approach - depend on systems to push potentially useful images.
• Notification Approach - depend on systems to tell you about potentially useful images.
• Query Approach - ask systems what images are available
• Subscribe Approach - sort of a cross between Query and Notification

Selection

Choosing images to make use of.

• Query Approach - evaluate/select based on image details returned in the query
• Notification Approach - see above; trust other system to have selected appropriately
• Keep-or-Toss Approach - get all potential images, evaluate directly and toss unneeded ones

Access

Getting the images.

• Sink Approach - see above
• Pull Approach - retrieve selected images

Update

How you know about updates to images you have copies of.

• Notification Approach
• New Copy?

Transport

How the images are conveyed

• Network vs Media
• Synchronous vs Asynchronous
• Whole vs Incremental

Different approaches have advantages and disadvantages depending on many factors such as network bandwidth, local storage capacity, image persistence times, immediacy of access needs, quality of image metadata, dependence on new software/systems, configuration/maintenance overhead, security needs, privacy needs, etc., etc., etc.

Do we need to elabourate whether access is direct from the source, or indirect through an intermediary (sync issues)?

Do we need to elabourate whether access is synchronous/immediate, or asynchronous/delayed?

What do we have to work with

DICOM Mechanisms

• C-Store
  • push across a typical network

• Retrieve
  • pull across a network, basically a C-Store invoked by the receiver

• Part 10 - Files
  • almost by definition push, asynchronous
  • profiled for a large variety of media: CD, DVD, USB, ZIP, Email, FTP
  • with/without compression
  • includes a MIME type

• Supplement 119 - Instance and Frame Level Retrieve

• Part 18 - WADO - Web Access to Persistent DICOM Objects
  • HTTP based pull across the web

• WG-10 Web Services
  • NADO - Notification of Availability of DICOM Objects
  • QIDO - Query by ID for DICOM Objects

• Supplement 118 - Application Hosting
  • includes mechanisms for accessing objects
  • File based or abstract model

• (DICOM Print)
  • Push to hardcopy

Current Image Sharing Profiles

Profile	Notification	Selection	Access	Update	Transport
"Local" Network
SWF (Mod-PACS)	Sink (C-Store)	Keep	Sink (C-Store)	PIR
SWF (PACS-Disp)	Query (C-Find)	Query (C-Find)	Pull (C-Store)	none
ARI	Query?	Query (C-Find)	Pull (C-Store)	none
TCE (PACS-Dest)	Sink (KIN Tag)	Keep-or-Toss	Sink (C-Store)	none
Sneakernet
PDI/IRWF	Sink	Keep-or-Toss	Sink (Media)	none
"Distributed" Network
XDS-I	Query (XDS.a)	Query	Pull (C-Store/WADO)	none

• Other Referencing
  • KIN
  • CPI, PGP
  • Image Fusion