1. [1] ISO TC215 / DICOM – Jan. 18, 2003 - Health Informatics – Messages and Communication – Web Access to DICOM Persistent Objects (WADO) Ad Hoc Group ISO TC215 WG2-4 / DICOM WG6-WADO ISO TC 215 WG2 – DICOM WG10, San Antonio, Texas, USA Emmanuel Cordonnier emmanuel.cordonnier@etiam.com Technical advancement on the New Work Item

2. [2] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Introduction l Users of medical information systems require rapid and reliable access to reports and images l Within computerized environments such access is increasingly based on web technologies l Access to relevant DICOM persistent objects is required without the need for duplication of such data objects l Clinicians need to have access: –either in native DICOM format for extensive manipulation using specialized software, –or rendered into a generic format (e.g. JPEG, PDF) that can be presented with off-the-shelf applications

3. [3] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Scope l new web-based service for accessing and presenting DICOM persistent objects l simple mechanism for accessing a DICOM persistent object from HTML pages or XML documents, through HTTP/HTTPs protocol, using the DICOM UIDs l NOT a way for searching DICOM images from the web, using parameters such as the Patient ID l this standard relates only to DICOM persistent objects

4. [4] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Normative references l DICOM PS 3.0, Digital Imaging and COmmunication in Medicine l IETF RFC2045 to 2049, Multipurpose Internet Mail Extension (MIME) l IETF RFC2396, Uniform Resource Identifiers (URI): Generic Syntax l IETF RFC2557, MIME Encapsulation of Aggregate Documents, such as HTML (MHTML) l IETF RFC2616, Hypertext Transfer Protocol -- HTTP/1.1 l IETF RFC3240, Application/dicom MIME Sub-type

5. [5] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Patient IE Image IE Patient IE Study IE Series IE Study IE Series IE Image I Patient IE Study IE Series IE DICOM Overview Patient IE Study IE Series IE SOP Image IE Pixels (compressed or not, depending of the TransferSyntax) Image Object Objects StoreQ/RPrint Services Worklist

6. [6] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Web Access to Persistent DICOM Objects 1-Retrieve one "entire document" (either in a presentation view or as a data set) using its "Persistent Document Instance UID" 2-(For later) Retrieve very specific extracts of a document by "Persistent Document Instance UID" Persistent Objects Repository Client Accessing Healthcare Documents e.g.EPR Retrieve a "presentation view" Retrieve a "Data Set" "Form of the reference" Data Set "Retrieve": -Preferred transfer Syntax -Default transfer Syntax ? Presentation View "Retrieve": -Type of encoding for images (JPEG, GIF, etc.) -Type of document presentation format (PDF, HTML, CDA-L1) -Size of Images Intent is not to offer a "Query": - Need is only to get access to an object Courtesy of Charles Parisot

7. [7] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Terms and definitions l DICOM Persistent Object –An instance of a data object as defined by DICOM PS 3.3 that has been allocated an unique identifier in the format specified for SOP Instance UID in DICOM PS 3.3 and has been chosen as an object to be saved securely for some period of time. l Web Client System –System using Internet technologies (web, e-mail…) interested for retrieving DICOM Persistent Objects from a Web Enabled DICOM Server, through HTTP/HTTPs protocol. l Web Enabled DICOM Server –System managing DICOM Persistent Objects and able to transmit them on request to the Web Client System. l Web Access to DICOM Persistent Objects –Service enabling Web Client System to retrieve DICOM Persistent Objects managed by Web Enabled DICOM Server, through HTTP/HTTPs protocol.

8. [8] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Applications l Reference to an image or to an interpretation report in an electronic patient record (EPR) l Reference to images included into an e-mail for advice request in a second opinion context l Reference to images included into an e-mail for hospital-doctors communication of interpretation report relating images l Reference to interpretation reports, images and waveforms into an hospital-doctors communication web server

9. [9] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Scenario: form the reference Images Store Image Manager & Archive Report Export Report Repository Acquisition Modality Images Retrieve Report Store Radiology dept Reference to images Reference to images Clinical Documents Repository Clinical dept Interpretation

10. [10] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Typical scenario: form the reference l The radiologist performs an acquisition creating DICOM images l He interprets the images producing a DICOM SR including reference to some significant images l He exports the DICOM SR as an HL7 CDA including those references to « external observations » (instance, series and study UIDs as different « id » sets, and « path » of the DICOM System in the « reference ») l The CDA is stored into the EMR/EPR/EHR database, using patient information for selecting the right record

11. [11] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Scenario: web access Images Store Image Manager & Archive Report Export Report Repository Acquisition Modality Images Retrieve Report Store Radiology dept Reference to images Reference to images Clinical Documents Repository Clinical dept Interpretation Clinical Document Consultation Web Access to DICOM Persistent Object

12. [12] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Typical scenario: web access l A clinician consults the CDA (the stylesheet builds the « URI » using the « reference » of the « custodian » which provided the CDA, completed by the « Web Access to DICOM Persistent Objects » parameters) l The clinician clicks on one « image » link l The WADO service, implemented as an HTTP script, build a « DICOM FIND » message using the parameters (object=1.2.32.…&series=1.2.32….), and retrieve the image form the DICOM server l It creates the HTTP response body as a MIME part (either application/dicom, or image/jpeg)

13. [13] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Examples of implementation DICOM Objects Database DICOM Interface Web Interface DICOM Q/R Web Access to Dicom Persistent Objects DICOM Objects Database DICOM Interface Web Gateway DICOM Q/R Web Access to Dicom Persistent Objects Web Client System Direct Interface Gateway Flexibility for the client to be implementted either as new system or on existing system Flexibility for the client to be implementted either as new system or on existing system

14. [14] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Interaction Diagram Web Enabled DICOM Server Object(s) request (HTTP GET) Object(s) send (HTTP response header and body) Web Client System

15. [15] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Syntax of the HTTP GET method l Syntax defined by the RFC2396 (URI) l http:// ? l e.g: –http://www.hosp.fr/dicom/wado.asp?study=1.2.3.21 The « Web Access to DICOM Persistent Object » standard defines only the Path of the Web Enabled DICOM Server WADO Parameter(s)

16. [16] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Selection Parameters l [study[series[object[frameNumber]]]] –study => UID of the study containing the object(s) –series => UID of the series containing the object(s) –object => UID of the single object (Service Object Pair SOP) –frameNumber => number of the selected frame (multiframe image objects)

17. [17] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Image Parameters [transferSyntax] [rows][columns][imageQuality] [presentation|[windowCenter windowWidth]] –transferSyntax => DICOM UID of the transferSyntax to be applied to the image (lossy/lossless compression) if returned as a DICOM MIME type. Implicit and Big Endian TS shall not be used. –rows => maximum number of pixels (vertical) –columns => maximum number of pixels (horizontal) –imageQuality => controls the level of compression –windowCenter / windowWidth => controls the luminosity and the contrast of the B&W image –presentation => UID of the Presentation State SOP to be applied on the image

18. [18] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com MIME type of return object(s) The MIME type(s) of the object(s) contained in the HTTP response are listed in the parameter of the GET method multipart/related if multiple objects (all of the series / study, or all the frames of a multiframe sequence retrieved in JPEG). All the included parts shall have the same MIME type. application/dicom for all objects, or a different MIME type for converting the DICOM object, depending of the nature of the object

19. [19] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com MIME type of image object(s) application/dicom. The transferSyntax parameter applies. If the Web Enabled DICOM Server cannot convert the image(s), it send it/them uncompressed (Explicit VR Little Endian). image/jpeg possible for all image objects. If multiframe and more than one frame to be retrieved, embedded into a multipart/related video/mpeg for multiframe image objects

20. [20] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com MIME type of Structured Reports application/dicom application/x-hl7-cda-level-one+xml for converting the SR into CDA (see HL7 Imaging SIG /DICOM WG20) text/plain for « minimal » version of document text/rtf for « Word » version of document application/pdf for « stable » version of document, potantially containing images text/html a priori without the images (to contained into only one file). The reference to the images can used the WADO syntax.

21. [21] ISO TC215 / DICOM – Jan. 18, 2003 - emmanuel.cordonnier@etiam.com Security aspects l It is clear that the information contained within DICOM objects may be considered as protected healthcare information (PHI). The protocol used, that is HTTP, can be replaced by HTTPs, which is its secure extension, for that purpose. This standard does not introduce any specific requirements on the security aspect compared to any access to PHI through the web.