Dicom Basics 2003
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Transcript of Dicom Basics 2003
The Electronic Healthcare Enterprise: A Primer on PACS
& Integrated Workflow
DICOM Basics All I Really Need to Know!
January 2003
DICOM Basics
Finding your way through the DICOM Maze . . .
DICOM Basics DICOM Myths
There is a DICOM Genie that will cure all my problems!
DICOMGenieTrust
ME!
DICOM Basics
What is DICOM? Acronym for . . .
Diagnostic Imaging and COmmunications inMedicine
A standard for data exchangeA common information model
Patient
Study
Series
Image
has
contains
contains
NameMRNAge
DICOM Basics
DICOM AnalogyMaking a phone call
Use your new Digital/1X enabled cellular phone to call for your messages.
The call does not go through . . .
What is the problem?The area you are in does not support Digital enabled phones - only analogue phones!
Example of a low-level communication failure.
DICOM BasicsYou get to a land line and make the call . . .
Your message says to call Antonio Correlli in Italy requesting you to speak at his conference.
You call Antonio’s office and the person who answers does not speak your language nor do you speak their language.
It is now established the hardware works (compatible), BUT, languages do not match and so still no communications.
DICOM Basics
Fortunately, Antonio’s cousin happens to be in the office and does speak English - so you are suddenly able to communicate.
In preparation of your trip you ask what temperature it is in Italy so you can pack appropriately. The cousin says it is 37 degrees at this time of year. The plan is to pack warm clothes.
You arrive 10 days later in Italy and it is very hot!
DICOM Basics
Antonio’s cousin told you the temperature he is most familiar with; 37 degrees – Celsius.
Your assumption was Fahrenheit.
What is the problem?
Differentiation of units between communications.
DICOM Basics
You informed Antonio’s office of your need for two beds in your room. They reply it will not be a problem.You arrive at your room with your wife and two children. The room has two single beds.What is the problem?They thought you were bringing a co-worker and did not understand your need to bring your spouse and children.
DICOM Basics
Technology Communications Requires Compatibility in . . .
Hardware – compatible phone systemsProtocols – common languagesDefinitions – units of temperatureModels – definition of a room with two beds
DICOM Basics
DICOM addresses image communications needs
What information do you want to communicate?
What do you want to do with that information?
DICOM Basics
DICOM example courtesy of
Steven C. Horii, M.D., F.A.C.R.Department of Radiology
University of Pennsylvania Medical Center
DICOM Basics
Why DICOM?
OPEN SYSTEMS
To achieve a higher level of communication, leading to increased efficiency and better workflow
Enables technology to work for the user
To facilitate connectivity and interoperability of medical imaging equipment
DICOM Basics
Who uses DICOM?Modality Providers, PACS Component Providers, Interface Engines
Who talks DICOM?Modalities, PACS, HIS & RIS via PACS Gateway/Broker and brokerless
Is there a DICOM Version 4.0 on its way?No, the standard is constantly evolving – changes every two months – DICOM has removed the 3.0 version in favour of the acronym of DICOM
DICOM BasicsDICOM is Not:
The answer to all your networking problems
A networking architecture nor dependent on network architecture
Available for all older modalities
A static standard – never more than 2 month old
Easy to understand
Does NOT Guarantee Interoperability
Does NOT cover every operation of PACS such as image deletion, migration or pre-fetching
DICOM Basics
DICOM is . . .Based on conformance with the Open System Interconnect (OSI) reference model
OSI defines a 7-layer protocol stack
DICOM is an “application-level” standard, which means it exists inside layer 7 (the uppermost layer)
DICOM BasicsDICOM provides:
Standardized formats for imagesA common information modelApplication services Services for communication across a network and on removable mediaVoluntary Conformance Statements – does not confirm interoperability between different devicesProtocols for communication
• Point to Point Communication• Not a Broadcast Communication like HL-7
DICOM BasicsDICOM Standard Sections
Part 1 Introduction & OverviewPart 2 ConformancePart 3 Information Object DefinitionsPart 4 Service Class SpecificationsPart 5 Data Structures & SemanticsPart 6 Data DictionaryPart 7 Message ExchangePart 8 Network Communications Support for
Message ExchangePart 9 Point-to-Point Support Communications
Support for Message ExchangePart 10 Media Storage and File Format for Media
Exchange
DICOM BasicsDICOM Standard Sections
Part 11 Media Storage Application ProfilesPart 12 Media Formats & Physical Media for
Media InterchangePart 13 Print Management Point-to-Point
Communications SupportPart 14 Grayscale Standard Display Function
Part 15 Security Profiles
DICOM Basics
DICOM Engineer DICOM
Engineer
and work on the standard some more!!!
DICOM Basics
All I technically really need to know . . .
DICOM Basics
To successfully use DICOM in a multi-vendor environment there needs to be a correct matching of services and roles.
How is this achieved?
DICOM BasicsDICOM Service Classes are divided into multiple functional areas. The most relevant Service Classes apply to the following functions:
StorageQuery and Retrieve (Q/R)PrintSecondary CaptureModality Worklist ManagementModality Performed Procedure StepStorage CommitmentPrinter ConfigurationInterchange Media Storage
DICOM BasicsDICOM Service Class Principles
Each Service Class is divided into Users and Providers
Users – use the service of another device
• Service Class Users - SCUProviders – provide the service for users
• Service Class Providers - SCP
DICOM BasicsDICOM Service Classes
DICOM Service Class Users (SCU)DICOM Service Class Providers (SCP)
DICOM Service Class User – Uses a service of another device
Example – DICOM Workstation uses the service of a DICOM printer to print images
DICOM Service Class Provider – Provides a service to another device
Example – DICOM Archive provides the service of storing patient exams sent from MRI
DICOM BasicsDICOM Storage
Most common Service ClassEnables the exchange of images and other DICOM Objects between devicesConsists of a DICOM Header containing patient demographics, specific attributes and instructions related to the image that is contained within that DICOM file from that specific modality – Plus –the image data that comprises that digital imageNative DICOM interface facilitates complete image manipulation and post image processing
DICOM BasicsDiagnostic
Workstation
DICOM Storage SCUDICOM Storage SCP
DICOM Storage
DICOM Basics
DICOM Query/RetrieveFacilitates the query of databases or other devices for informationFacilitates the retrieval of a copy of the objects such as images from the current residence to a new desired locationExample:• Query a MR for a specific patient and retrieve the
patient’s exam from the MR to the Diagnostic Workstation
DICOM Basics
DiagnosticWorkstation
DICOM Query SCU
DICOM Query SCP
DICOM Query/Retrieve
DICOM BasicsDICOM Print Management
Facilitates the print of DICOM files/images from any print location to any DICOM printer located on the networkTransfers the instructions to print along with the data to printExample:• The Diagnostic Workstations sends 12 images
from a MR exam composed in a specific order to the DICOM laser printer
DICOM Basics
Laser Printer
DiagnosticWorkstation
DICOM Print SCU
DICOM Print SCP
DICOM Print SCU
DICOM Print
DICOM BasicsDICOM Secondary Capture
Facilitates the capture of images from non-DICOM legacy modality using either frame-grabber technology or digital stream to compose a DICOM image fileDoes not acquire all the specific image attributes and instructions – therefore offers limited image manipulation and no post-processing abilitiesExample:• Film digitizer acquires film-based images • DICOM Interface Black Box enables legacy Ultrasound
unit to share images using DICOM format with limited functionality
DICOM Basics
DICOM SecondaryCapture Diagnostic
Workstation
DICOM Print SCU
DICOM SecondaryCapture SCP
DICOM BasicsConversion of legacy systems to DICOM
“Legacy” Systems – “existing equipment that will not be replaced for a period of time”Examples – Ultrasound, CT, Angio, R/F
Two methods for conversionOEM software upgrade – “Native” DICOM
• Modality provides a digital output of image data with all appropriate DICOM header fields populated
DICOM Black Box – vendors Merge, Dejarnette, Kodak, etc.
• Frame Grabbers – 8 bit – Does a video frame grab to digitize the image
• DICOM Secondary Capture – 12 bit – does not populate all appropriate DICOM header fields for image manipulation – I.E. Window/leveling
DICOM Basics
DICOMConversion
Box
DICOMSecondary
CaptureSCU
Legacy Radiography/Fluorography
DICOM Secondary Capture
DICOM BasicsModality Worklist Management
Facilitates the transfer of patient demographic information between the RIS and a modalityEliminates the need to re-key dataEliminates human error during re-entry of data – ensures data integrityExample:• Patient data is transferred from RIS through PACS
Gateway/Broker to MRI unit
DICOM Basics
RIS
PACS Gateway/Broker
HL- 7Patient Demographics
DICOM ModalityWorklist Management
Broker Environment
DICOM Basics
Modality Archive
RIS
HL - 7 PatientDemographics
DICOM ModalityWorklist Management
Broker-less Environment
DICOM BasicsStorage Commitment
Facilitates a device to request another device to accept storage responsibility for images forwardedFacilitates the modality to delete local images once the archive has committed to store imagesExample:• MR forwards a storage commitment message to
the archive to confirm the storage of Mary Smith’s MRI exam
DICOM Basics
Modality Archive
DICOMStorage Commitment
DICOM Storage Commitment
DICOM BasicsModality Performed Procedure Step
Informs other devices (RIS and PACS) when specific patient exams are started, current status, and complete (aborted)Messages how many series, and images in each series in each exam, consumables, radiation dose delivered, etc.Example:• MRI sends MPPS message to RIS indicating Mary Smith
MR head exam is complete to trigger scheduling and billing
• MRI sends MPPS message to PACS Archive indicating that there were 3 series – Series 1 contain 112 images, Series II contain 78 images, etc. to ensure the archive has received all images and can store all images.
DICOM BasicsDICOM Performed
Procedure Step
Modality Archive
RIS
DICOM PerformedProcedure Step
Triggers Schedule Update &Billing Information
Triggers the addition of theexam to a reporting Worklist -confirms images for storage
DICOM PerformedProcedure Step
PACS Gateway/Broker
DICOM BasicsInterchange Media StorageDefines the formats for file storage; compression; what images are written to media“Basic Cardiac Angiography” is most commonly accepted/ implemented
ISO 9660 CD-RLossless JPEG compression512 matrix 8- bit multi-frame cardiac X-Ray Angiography
Additional DICOM specified profiles:General purpose exchange of any uncompressed images on CD-RBasic and 1K Angiography images compressed with lossless JPEG on CD-RCT & MRI images compressed with lossless JPEG on CD-R and 130 mm MODUltrasound Images uncompressed or compressed on CD-R, 90 mm and 130 mm MOD
Additional profiles will be added to the standard as applications and media change
DICOM Basics
CD Burner
Hospital A
Clinic B
Referring PhysicianOffice
DICOMInterchange Media
DICOM BasicsImage Object Definitions – (IOD)
IOD’s describe the data structures that contain image data and information• Example: CT is 12 bit grayscale vs. Ultrasound
is 24 bit colourTwo key IOD sub-classes –• Single Frame Images and Multi-Frame Images
Affect two key PACS components – Archive and Image Display applicationsRFP Requirement – all current and future applications for PACS
DICOM BasicsSingle Frame Images- Currently Available
Secondary Capture (SC) Scanned FilmsComputed Radiography (CR)Digital X-Ray (DR)Computed Tomography (CT)Magnetic Resonance (MR)Ultrasound (US) Nuclear Medicine (NM)Radiotherapy (RT) Image, Dose, Plan, Structure Set, RecordHardcopy Image (HC)Grayscale Softcopy Presentation State Store (PR)Positron Emission Tomography (PET)
DICOM Basics
Multi-Frame Images – Currently AvailableUltrasound (US)Nuclear Medicine (NM)X-Ray Angiography (XA)X-Ray Fluoroscopy (XRF)
DICOM Basics
Additional IOD’s Identified –Intra-oral Radiography (IO)Hardcopy Image (HC)Visible Light (VL) Endoscopy, Microscopy, PhotographyWaveforms (WV), Including ECG, Hemodynamic and Audio – Time based waveformsStructured Reporting (SR)
DICOM BasicsExample:
MRI sends an exam to the PACS archiveDICOM Storage SCU
Archive receives the exam and stores it DICOM Storage SCP
Archive sends the exam to the Diagnostic Workstation
DICOM Storage SCP
Diagnostic Workstation displays the exam to be interpreted
DICOM Storage SCU
DICOM SecondaryCapture
Patient DemographicsHL - 7
DICOM Modality Worklist Management
DICOM Storage
PACS Gateway/Broker
DICOMConversion
Box
RIS
PACS Archive
DiagnosticWorkstation
ReferringPhysicians
Verification
DICOMSecondary
Capture DICOM Storage
DICOM Query
DICOMRetrieve
DICOMPrint
Questions