what’s new in dicom harry solomon, ge healthcare rsna 2007

What’s New in DICOM

Harry Solomon, GE HealthcareRSNA 2007

2What's new in DICOM - RSNA 2007

DICOM is the International Standard for Medical Imaging and related information: images, waveforms, derived measurements and assessments, image presentation control, and workflow management for the imaging department

Published as NEMA PS3 and as ISO 12052


Agenda

• The DICOM Change Process• Images• Image Processing & Reporting• Workflow• Specialties• Get Involved!


The DICOM Change Process

• Continuous process for evolution of the standard– It’s just “DICOM”, not DICOM 3.0, 3.1, etc.– Conformance is to SOP Classes, not to a ‘version’ of the

Standard

• Change Proposals for minor corrections– About 100 / year – Anybody can submit

• Supplements for major changes – new object types, services, compression schemes– About 10 / year– Require Work Item approved by DICOM Standards

Committee

• Consolidated edition published every year– Most recently, January 2007– Available free at DICOM web site

Images

Information Object Definitions

and Image Access


Multiframe Images

• Multiframe objects to support 1000+ slice studies– Image header supports functional group

attributes changing during acquisition– Dimensions allow multiple views of data

• Common structure used for all new image IODs– Sup 110 Ophthalmic Coherence Tomography

(Adopted August 2007)– Sup 116 3-D X-ray (Adopted January 2007)– Sup 117 Enhanced PET (in Letter Ballot)

– Sup 43 Enhanced Ultrasound (in Public Comment)

– Sup 125 Breast Tomosynthesis (in Public Comment)


Single-frame to MultiFrame

N Objects, N Headers

N Frames, One Header

Pixel dataDimension dataPer-frame headerFixed Header


The Per-Frame Header

Other attributes

Per-frame Functional Groups Sequence

Shared Functional Groups Sequence

> Functional Group A

> Functional Group B

> Functional Group M

…..

Other attributes

Functional Groups with attributes constant

for all frames

Item 1 (Frame 1) Sequence of

Functional Groups for each individual frame

Pixel Data

Frame 1

Frame 2

Frame n

…..

> Functional Group C



…..

Item n (Frame n)




Item 2 (Frame 2)


…..

…..

…..

…..

> Functional Group K


Sup 119 Frame Level Retrieve

• If we have 1000+ slice image objects, how do we access the slice identified in the report as the Key Image?– Or, how to access a short video clip of a long endoscopy

video image object?– Many similar use cases needing one frame or a small

subset of frames from large multiframe image– Purpose of retrieval may not be diagnostic; compression

OK

• Proposed new Retrieve SOP Classes for subsets of frames– Request can include a preferred transfer syntax (i.e., type

of compression)– Returned object is a derived image with the requested

subset of frames, but with a different Instance UIDIn Public Comment


Sup 43 Enhanced Ultrasound

• Pixel frames may represent tissue, velocity, variance or power

• Multiple frames (up to 3) must be blended for proper display

• Enhanced blending pipeline required to render images

In Public Comment

Data Frame Modality

LUT (identity)

VOI LUT(optional)

PrimaryRGBAPalette

Color LUT

(optional)

Data Frame

Data Frame Modality

LUT (identity)

VOI LUT(optional)

SecondaryRGBAPalette

Color LUT

(optional)

OpacityLUT

(optional)

RGB

ProfileConnection

Space Transformation

RGB

ICC Input Profile

Real World Value Mapping


Presentation LUT

(identity)

Gray Scale Output asP-Values

Color Output as

PCS-Values

RGB (Input 1)

Real World Value +Units

Alpha 1

Alpha 2

RGB

RGB (Input 1)


Real World Value +Units

Alpha, Beta(Constants)

RGB (Input 2)

Convert to RGB (R=B=G)

Blending Operation

Multiply inputs and add the result

(Alpha 1) x Input 1 +

(Alpha 2) x Input 2

CLAMP

OR

OR

Alpha

(1-Alpha), Alpha

Alpha

MSB’s

LSB’s

Alpha,BetaLUT

outputs

OR

Modality LUT

(identity)

VOI LUT(optional)

Image Processing & Reporting

Segmentation, Registration, Structured

Reporting


Sup 111 Segmentation Image

• Derived image object– Multiframe, using functional group mechanism

• Multiple segments per object– Each segment linked to a categorization– Pixels show presence of category at pixel location– Binary (1-bit/pixel) or fractional (probability or

occupancy)

• Segments can be 2-D or 3-D• 3-D segmentation is typically in same

Frame of Reference as source image• Segments can be displayed as overlays on

source image Adopted August 2006


Segmentation Example

Segment Sequence

Other attributes

Item 1 (Segment 1)

Pixel Data

Frame 1

Frame 2

Frame 4

Item 2 (Segment 2)

Segment Number = 1

Segment Name = White Matter

Segment Category = Brain

Segment Type = White Matter

Segment Number = 2

Segment Name = Grey Matter


Segment Type = Grey Matter

Per-frame Functional Groups Sequence

Item 1 (Frame 1)

Segment Identification Sequence

Referenced Segment Number = 2


Item 1

Item 2 (Frame 2)



Item 1

Item 3 (Frame 3)

Frame 3

Shared Functional Groups Sequence

Item 1 (Shared – all frames)

Derivation Image Sequence

Item 3 (Segment 3)

Segment Number = 3

Segment Name = Lesion Part 1


Segment Type = Lesion

Item 4 (Segment 4) Segment Number = 4

Segment Name = Lesion Part 2


Segment Type = Lesion



Item 1

Item 4 (Frame 4)


Item 1

Item 1

Reference to source image (external object)


Sup 132 Surface Segmentation

• Work in progress – just released for Public Comment

• Segmentation using 3-D surface mesh (rather than voxel volume)

• First use of mesh technology in DICOM– Will also be used for future volumetric work,

including implant specification and surgical planning

In Public Comment


Sup 112 Deformable Spatial

Registration

• Composite Object that supports multi-image alignment

• 3 step algorithm– Pre-deformation matrix transform – Deformation using 3D grid of 3D deformation

vectors– Post-deformation matrix transform

• Facilitates further image processing, especially multi-modality image fusion and image pasting applications

Adopted August 2006


Structured Reporting

• Additional Templates for standard SR SOP Classes– Sup 128 Cardiac Stress Testing (Frozen Draft –

passed Ballot, awaiting final SNOMED and IEEE codes)– Sup 129 Cardiac Electrophysiology (in Public

Comment)

• Templates for specialty SR SOP Classes– Sup 127 CT Radiation Dose (Adopted October

2007)– Sup 130 Ophthalmic Refractive SR (in Letter

Ballot)– Sup 126 Colon CAD (in preparation)

• Harmonization with HL7– Sup 114 DICOM Encapsulation of CDA

Documents (Adopted January 2007)

Workflow

Substance Administration, Unified Worklist, RT Workflow,

Specimen Identification


Sup 107 Substance Administration

• Patient safety issue – “five rights” checking for contrast agents– Point of use verification for substances often “out of the

loop” of hospital pharmacy systems

• Three new DICOM services– Typically Modality as SCU interacting with HIS via gateway

SCP

• Query: Look up product characteristics – Given a barcode ID (from contrast agent bottle), get name,

active ingredient, concentration, etc.

• Query: Get substance administration approval– Based on agent, patient, route of administration; get

approval or warnings

• Report contrast used to HIS Medication Administration Record

Adopted January 2007


Sup 96 Unified Procedure Steps

• Simplification and merger of Worklist Management and Performed Procedure Steps – 1:1 relationship between scheduled and performed

steps– A single IOD that combines attributes of both – C-FIND to query worklists– N-CREATE to create new scheduled procedure steps– N-GET/N-SET to update – N-EVENT-REPORT to monitor and report progress

• Intended to meet the needs of– Radiation Therapy Scheduling and Monitoring– Scheduling and Monitoring CAD systems– Proposed new scheduling activities

Frozen Draft for Trial Implementation


Sup 74 Radiotherapy Worklist

• Supports automated worklist management and machine parameter verification for the integration of multi-system radiation therapy planning and treatment

• First usage of Unified Procedure Step• Also defines three new objects / SOP Classes

– RT Beams Delivery Instruction (Composite)– RT Conventional Machine Verification (Normalized)– RT Ion Machine Verification (Normalized)

• Real implementation and evaluation needed – in conjunction with IHE Radiation Oncology

Frozen Draft for Trial Implementation


Sup 122 Specimen Identification

• Support for pathology lab workflow, specimen-based imaging– Gross specimens, blocks, vials, slides– Image-guided biopsy samples

• Retires current Specimen Identification Module, adds new Specimen Module at image level of hierarchy– May affect applications that implement current Module

(if any)

• Update to Modality Worklist to allow Specimen Module– Enables automated slide scanning devices to fully

populate header

• Update to Modality Performed Procedure Step to identify imaged specimen– Allows LIS to track images for specimens

In Public Comment


• Biomed engineering– Supp 124 Communication of Display Parameters

(in preparation)– Administrative support for monitor calibration

• Research / Biomarkers– Supp 118 Application Hosting (in preparation)– Image analysis programs run on any workstation

• Surgery– Sup 131 Implant Description (in preparation) – Supports 3D model of bone-mountable implants

• Dentistry / Radiology– Sup 123 Structured Display (in preparation) – Captured screen layout of multiple images (with

presentation states) for dental series, radiology conference, etc.

Specialties


Get Involved!• Get the DICOM Standard (free!)

– http://dicom.nema.org/medical/dicom/2007/ (annual issue)– ftp://dicom.nema.org/medical/dicom/final (changes between

issues)• Ask questions/discuss on the DICOM Newsgroup

– http://groups.google.com/group/comp.protocols.dicom• Respond to Supplements released for Public Comment

– http://www.dclunie.com/dicom-status/status.html• Submit Change Proposals

– mailto:[email protected] • Join a DICOM Working Group

– See list in http://medical.nema.org/dicom/geninfo/Strategy.pdf

• Attend the DICOM International Conference and Seminar, Chengdu, China, April 8-10, 2008– http://dicom.nema.org/Dicom/DCS-2008/

• Build the new DICOM capabilities into your products– Your URL here!