DICOM INTERNATIONAL CONFERENCE SEMINAR Oct 9 11 2010

DICOM INTERNATIONAL CONFERENCE & SEMINAR Oct 9 -11, 2010 Rio de Janeiro, Brazil Exchanging Imaging Data Cor Loef Philips

Exchanging Imaging Data • Objective: This presentation will answer the following question: – What are the types of DICOM objects and how do we move them around, i. e. over a network as well as on media?

Exchanging Imaging Data • Agenda – Main Classes of Objects: Images, Presentation States, Structured Reports, Encapsulated Objects – Pushing Objects, Pulling Objects, Finding Objects and Retrieving Objects – DICOM: a Protocol vs a File Format vs a product Internal Data Representation – Use of Media: CDs, Memory Sticks, Email, WADO

Information Object Definition (IOD): IE’s Modules Attributes

Information Object Definition (IOD): • DICOM Composite Objects: For persistent, “permanent” objects using DIMSE-C commands (C-Store, C-Move, CFind…) l Multiple IE’s: relate to DICOM Information Model (Patient-Study-Series-Image…) l Cannot be changed or modified, if so, create a new object with new SOP Instance UID l

Multi-frame Objects: Vector • • Ultrasound Multiframe Nuclear Medicine XA and RF New objects: MR, CT, PET, XA-XRF (new), X -Ray 3 D, US 3 D • VL and Ophthalmology • Any future new objects: NM (new)

Structured Reports: • Same structure as Images: – “main body” contains report and/or other information (measurements, etc. ) instead of pixels – Same structure for header – Same study information – Modality is “SR” – Has a tree structure

SR example (IHE simple report):

SR example (Key Image/Object Note KON):

Encapsulated Objects (SC and PDF): • Some objects are difficult to encode as “native” objects: • Secondary Capture (SC): – Digitized film, captured video, scanned documents • Encapsulated PDF: – typically for bone scans and eye care (topographic maps)

Softcopy Presentation State: - Present images (almost) identical on softcopy media in standard manner - Separation of Stored Image Instances from Display characteristics and changes - Includes shutters, image annotation, spatial transformation, display annotation

Softcopy Presentation State: Solution: - Create Composite object containing the presentation state parameters ONLY (no images) - Link this Composite object to one or more images (Series, Images) - Store within same Study; Modality “PR” - Communicate with regular Storage service (C_Store); Retrieve with Query/Retrieve service

How do we move these objects around? Pushing, Pulling Objects (Storage SOP Classes), Finding Objects (Information model/FIND), Retrieving Objects (Move/Get)

Storage Service class: Information System Modality Push/ PACS Push Printer DICOM C-Store Modality Archive PACS Display

Storage Service class: l Transfer composite objects (e. g. images, reports, RT plans, waveforms) from one AE to another l One AE functions as the SCU, the other as SCP l SOP classes use C-Store DIMSE-C service l Information is stored in some medium, accessible for some time (Issue! Might need Storage commitment!)

Query/Retrieve Service class: SCU/ SCP Information System Modality Pull/PACS Pull Printer DICOM C-Find DICOM C-Move Archive Modality PACS Display

Query/Retrieve Service class: l Simple Query, NOT full SQL: l Query: Basic image information query (“FIND”) using small set of common key attributes l Retrieve: Either from remote AE (“GET”), or Xfer from one AE to the other (“MOVE”) l Note: “GET” rarely supported l Extensions allow retrieval of selected frames of a multi-frame

Query/Retrieve Service class: Note: Most vendors also support a proprietary, direct protocol DICOM I/F SQL database (Informix, Sybase, Oracle)

Query/Retrieve Service class: l Key Attributes: l U: Unique l R: Required l O: Optional Image IOD Pat name Pat ID ----- Keys

Keys for FIND: Patient’s Name (0010, 0010) R Patient ID (0010, 0020) U Study Date (0008, 0020) R Study Time (0008, 0030) R Accession Number (0008, 0050) R Study ID (0020, 0010) R Study Instance UID (0020, 000 D) U Modality (0008, 0060) R Series Number (0020, 0011) R Series Instance UID (0020, 000 E) U Instance Number (0020, 0013) R SOP Instance UID (0008, 0018) U

Query/Retrieve Service Class: Q/R SOP Classes use: l C-Find: l SCP matches all keys specified in the request against it’s database l May be at Patient, Study, Series or Image level l SCP provides Response for each match containing values for all keys and all requested, known attributes l Cancel if needed

Query/Retrieve Service Class: Q/R SOP Classes use: l C-Move: l SCU provides unique key values for needed SOP instances l SCP initiates C-Store(s) as SCU (on a separate Association) l SCP can issue C-Move responses with status pending until all C-Stores are completed or after each Store (see Conformance Statement) l Can issue Cancel at any time

Protocols, Files, Storage • Protocols: – DICOM defines a standard communication protocol (PDU, TCP/IP, addressing: port #, AE title) • Files: – DICOM also defines a standard for files on media: “Part-10 files” = meta information + a SOP instance – Media includes CD, DVD, Memory Sticks, etc. – Part-10 file format is also extended for zip files, email, and web access (WADO)

DICOM Media: • Meta-file header: • Transfer syntax (encoding) • SOP Class • Who generated it • Compliant with standard OS’s • DICOMDIR required for exchange media • Index/database of files

DICOM Media Specifications: Part 10 DICOM Application Entity Basic Dir. Service / Object Pairs Part 12 Part 11 DICOM File Format Media Formats: e. g. File data structures Physical Media: e. g. CD-R; 90 mm MOD, etc.

Protocols, Files, Storage: • Device Internal Storage: – DICOM defines how images go in/out of device – DICOM does NOT define how to archive images (there is NO archive standard) – Some vendors keep images in DICOM format, some pre-process images using a compression method, either standard or proprietary – Migration of both PACS databases and archives are common when changing releases, vendors, etc.

Conclusion: • DICOM objects include: – not only images – but also SR’s, Presentation States, and encapsulated objects • DICOM images are moved around using: – the DICOM protocol – the DICOM Part-10 file definition • There is NO DICOM archiving standard, some archives store “natively”, some do not

DICOM INTERNATIONAL CONFERENCE & SEMINAR Oct 9 -11, 2010 Rio de Janeiro, Brazil Thank you! Cor Loef: cor. loef@philips. com www. philips. com