Toward DICOM n-Dimensional Presentation State Joe Luszcz, Co-Chair DICOM Working Group 11.

Toward DICOM n-Dimensional Presentation State

Joe Luszcz, Co-ChairDICOM Working Group 11

Viewing 3D/4D Volume Data

A volume dataset isn’t visually useful by itselfWe need meaningful Views of the volume data

24 June 2011 Towards DICOM n-Dimensional Presentation State 2

Viewing 3D/4D Volume Data

There are a number of ways of viewing volume data Multi-Planar Reformatted (MPR) slices of the volume Rendering of the voxels in the volume (VR) Rendering of surfaces derived from the volume

dataset or from a library of implantable devices (SR)

Fusion of above representations


axial slice MPR views VR view VR + SR view

Multi-Planar Reformatting

Multi-Planar Reformatting is a visualization technique that creates a 2D image depicting only volume data lying on or within a specified slice thickness of a planar or curved surface through a volume


Rendering of Volumes

Volume Rendering is a visualization technique in which a view of a volume dataset from a particular viewpoint is obtained while possibly allowing both near and far structures to be visualized by making nearer structures semi-transparent.


Cropping may also be performed to removed unwanted foreground structures.

Rendering of Surfaces

Surface Rendering is a visualization technique in which a surface derived from voxel data or models (rather than volume data) are viewed from a particular viewpoint


These surfaces may be obtained by

segmentation from a volume dataset

geometric models from a library of objects such as implants or surgical tools

co-aligned with voxel data in a fusion image

Presentation State The processing required to create a View from a volume and

its related inputs I’ll call a “Display Algorithm”


Display Parameters

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.

Persistent Storage

Presentation State

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SourceInformation

ViewDisplay

Algorithm

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These Display Parameters may be saved so that the particular View might be re-created at a later time (on the same device or on a different device). This saved set of Display Parameters is called a Presentation State

The Display Algorithm requires a set of Display Parameters to specify the particular View to create

Clinical Perspectives

Presentation workflow varies depending on the role of the clinician Diagnosis Intervention and Surgery


Diagnosis

Physician or technician acquires volume data and creates MPR and volume render views on the imaging device

Reviewing physician displays Views on a review device Views may be changed or added during review Measurements may be taken on the image Views or

calculated algorithmically from the volume data Annotations may be made on the Views and new Views

saved as documentation of the diagnosis A report is created, which may reference one or more

Views


Diagnosis Workflow


Modality-specifi c image

creation

Modality.

Cartesian Volume

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Volume Slice

Volume Render

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Volume Render

Parameters

Slicing Parameters

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Persistent Storage

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Presentation States

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Export of Volume Dataset

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Volume Slice

Volume Render

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Volume Render

Parameters

Slicing Parameters

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.

Presentation States

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Changes

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Presentation States

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New

Intervention and Surgery

There are many different types of interventional treatment specialists and procedures, each with specific needs

Cardiologist patching a ventricular septal defect – needs to size the patch and guide it into place

Orthopedic surgeon repairing a complex fracture – needs to plan the procedure (including choice of implants) and refine the plan during the procedure

Oncologist planning radiotherapy – needs to visualize iso-dose profiles and prepare a treatment plan

Each clinical specialty and each type of procedure utilizes different volume viewing techniques


Intervention/Surgery Procedure Support

Views are created to determine Exact locations and shapes of lesions Specific tissue types and structure surfaces for segmentation Size and type of implants and surgical tools Routes for surgical or interventional access Mapping of specific actions (e.g., animated procedure views)

Views are dynamically updated to guide the work Fusion of pre-procedure imagery (e.g. CT, MR, PET, etc.) with

intra-procedure real-time imagery (e.g. US) to track progress Removal of surfaces or objects obscuring desired view Illustration of steps to stay on-plan Guidance of tools and/or implants to procedure site Before and after Views to document and support follow-up


text

Persistent Storage

Presentation State

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.

Intervention/Surgery Pre-Procedure


Display Parameters

ViewDisplay

Algorithm

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.

Input List

0..*

0..*

0..*

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Primary Patient Info(e.g., Volume Data)

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Data Derived from Primary Patient Info

Derivation Parameters

Derivation Algorithms

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Data Models(e.g., Implant

Devices)

Intervention/Surgery Procedure


Presentation State

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textDisplay Parameters

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Input List

Display Parameters

ViewDisplay

Algorithm

.

.

Input List

0..*

0..*

0..*

Presentation State

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.

New

Modify View

.

.Persistent Storage

.

.

Data Models(e.g., Implant

Devices)

Primary Patient Info(e.g., Volume Data)

Data Derived from Primary Patient Info

DICOM Working Group 11

Presentation State is the charter of DICOM Working Group 11

WG-11’s current goal is to create a DICOM standard for Multi-Dimensional Presentation States

Process and current status Gathering and reviewing clinical use cases Deriving requirements from clinical use cases Seeking consensus on requirement glossary Creating the draft supplement document

capturing the approach we plan to use, preparing for First Read


Call for Participation

We would value your participation in the development of the n-D Presentation States standard:

To provide or review clinical use cases To review requirements To monitor the ongoing development work To actively participate in the development …

Contact: the author [email protected], or MITA secretary Stephen Vastagh

[email protected]


Thank you for your attention


Agenda

How do we view volume data? Role of Presentation State Clinical application of Presentation State

Diagnostics Intervention and Surgery

DICOM Standardization of Multi-Dimensional Presentation State

Call for Participation


Standardization Challenges

19

Most ObjectiveMost Interoperable

Most ProprietaryLeast Interoperable

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InputsInput characteristicsCropping, Clip Planes, VOIMPR geometry Plane/Curve location MPR view size Slice thicknessRender geometry Camera Lighting2D View Decorations Graphics TextAnatomic View designationEtc.

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Blending Grayscale/color maps Grayscale/color thresholdGeneral classification of algorithms Intensity Projection MIP MinIP AveIP Surface rendering Scanline rendering Ray casting Ray tracing

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Opacity mapsOpacity algorithmsRender space Scalar RGB

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Slicing algorithmsRendering algorithmsEdge Detection algorithmsSmoothing algorithmsFiltering algorithmsCropping and Sculpting algorithm parameters

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DICOM Standardization Process

DICOM Committee assigns work item Working Group (WG) chooses approach to follow

First Read review of approach WG creates a draft of the new standard

Public Comment review, release for comments WG revises draft to respond to comments

Letter Ballot review, release for letter ballot WG revises document to address ballot

comments Final Text review, create Final Text version of doc

Final Text document is now part of DICOM


Toward DICOM n-Dimensional Presentation State Joe Luszcz, Co-Chair DICOM Working Group 11.

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