Michael BurnsMartin Haidacher

Eduard Gröller

Ivan ViolaWolfgang Wein

CT scan with embedded Ultrasound data

Michael Burns - Contextual Medical Visualization

Poking needlesLiver biopsyRadio frequency

ablation

Procedure:Patient has CT scanNeedle path is plannedUses ultrasound probe to help guide needleDoctor views CT scan at time of procedure

Michael Burns - Contextual Medical Visualization

CT Scan Data Ultrasound Data

Michael Burns - Contextual Medical Visualization

Ultrasound embedded in dense volume

Michael Burns - Contextual Medical Visualization

Ultrasound embedded in sparse volume

Michael Burns - Contextual Medical Visualization

Ultrasound with contextual cutaway

Michael Burns - Contextual Medical Visualization

Volumetric dataTissue types differentiated and ranked

○ Important materials most visible○ Unimportant materials provide context

Ultrasound imageCaptured with 3D position and orientation of

probeRegistration between coordinate frames

[Wein05]

Michael Burns - Contextual Medical Visualization

Volumetric Data(e.g. CT Scan)

Volumetric Data(e.g. CT Scan)

Importance in the Transfer Function

Importance in the Transfer Function

Viewpoint InformationViewpoint Information Object of Interest(e.g. Ultrasound Plane)

Object of Interest(e.g. Ultrasound Plane)

Contextual Cutaway Views

Contextual Cutaway ViewsImportance-Driven

Shading

Importance-Driven Shading

Integrating Occlusion with Importance

Integrating Occlusion with Importance

Michael Burns - Contextual Medical Visualization

Volumetric Data(e.g. CT Scan)

Volumetric Data(e.g. CT Scan)

Importance in the Transfer Function

Importance in the Transfer Function

Viewpoint InformationViewpoint Information Object of Interest(e.g. Ultrasound Plane)

Object of Interest(e.g. Ultrasound Plane)

Contextual Cutaway Views

Contextual Cutaway ViewsImportance-Driven

Shading

Importance-Driven Shading

Integrating Occlusion with Importance

Integrating Occlusion with Importance

Michael Burns - Contextual Medical Visualization

Rank materials by relevance

1. Definition in volumetric spaceUses auxiliary volumeRequires preprocessing per dataset

2. Definition in transfer function spaceExtra value in transfer functionShared among datasets

Michael Burns - Contextual Medical Visualization

Material boundaries

F(x, y, z)

|F(

x, y

, z)|

Michael Burns - Contextual Medical Visualization

Volumetric Data(e.g. CT Scan)

Volumetric Data(e.g. CT Scan)

Importance in the Transfer Function

Importance in the Transfer Function

Viewpoint InformationViewpoint Information Object of Interest(e.g. Ultrasound Plane)

Object of Interest(e.g. Ultrasound Plane)

Contextual Cutaway Views

Contextual Cutaway ViewsImportance-Driven

Shading

Importance-Driven Shading

Integrating Occlusion with Importance

Integrating Occlusion with Importance

Michael Burns - Contextual Medical Visualization

Visual distinction between materialsEmphasis of important materials

Material propertiesColorOpacity

Lighting propertiesShading conveys detail

Michael Burns - Contextual Medical Visualization

Full Shading No Shading

Michael Burns - Contextual Medical Visualization

Full Shading Importance Shading

Michael Burns - Contextual Medical Visualization

Importance Shading

Emphasis: E

Shaded color: Cshaded

Subdued color:Csubdued = E * Cunshaded +

(1 – E) * Cshaded

Final color:Cfinal = I * Cshaded +

(1 – I) * Csubdued

Michael Burns - Contextual Medical Visualization

Michael Burns - Contextual Medical Visualization

Volumetric Data(e.g. CT Scan)

Volumetric Data(e.g. CT Scan)

Importance in the Transfer Function

Importance in the Transfer Function

Viewpoint InformationViewpoint Information Object of Interest(e.g. Ultrasound Plane)

Object of Interest(e.g. Ultrasound Plane)

Contextual Cutaway Views

Contextual Cutaway ViewsImportance-Driven

Shading

Importance-Driven Shading

Integrating Occlusion with Importance

Integrating Occlusion with Importance

Michael Burns - Contextual Medical Visualization

Object of interest obscured by volumeHigh importance

○ Should be visible○ May obscure object

Low importance○ Not necessarily visible○ May not obscure object

View-dependent cutaway structure

Michael Burns - Contextual Medical Visualization

v

Base

Clear

Object of Interest

Michael Burns - Contextual Medical Visualization

Small Large

Michael Burns - Contextual Medical Visualization

v

1

2

Base

Transition

Clear

Overlay

d

Michael Burns - Contextual Medical Visualization

Base Transition

Michael Burns - Contextual Medical Visualization

Base, Transition Overlay

Michael Burns - Contextual Medical Visualization

Base, Transition, Overlay Base

Michael Burns - Contextual Medical Visualization

Volumetric Data(e.g. CT Scan)

Volumetric Data(e.g. CT Scan)

Importance in the Transfer Function

Importance in the Transfer Function

Viewpoint InformationViewpoint Information Object of Interest(e.g. Ultrasound Plane)

Object of Interest(e.g. Ultrasound Plane)

Contextual Cutaway Views

Contextual Cutaway ViewsImportance-Driven

Shading

Importance-Driven Shading

Integrating Occlusion with Importance

Integrating Occlusion with Importance

Michael Burns - Contextual Medical Visualization

v = 1

= 0

1

0.75

0.5

0.25

0

Michael Burns - Contextual Medical Visualization

Fade material based on occlusion value between two occlusion thresholdsThresholds based on importance

Modify opacity:τu = I

τl = max(2 * I – 1, 0)

α’ = α * (1 – ramp(τu, τl, Ω))

Michael Burns - Contextual Medical Visualization

Base

Trans

ition

Clear

Overla

y

Liver (0.5)Liver (0.5) Vessels (0.99)Vessels (0.99)

Occlusion value (Ω)

α sc

ale

fact

or

0 10.5

Flesh (0.01)Flesh (0.01)0

1

τu = Iτl = max(2 * I – 1, 0)

Michael Burns - Contextual Medical Visualization

No cutaway(over draw)

Michael Burns - Contextual Medical Visualization

Simple cutaway

Michael Burns - Contextual Medical Visualization

Simple cutawaywith interior

Michael Burns - Contextual Medical Visualization

Interior becomes overlay region

Michael Burns - Contextual Medical Visualization

Transition area added

Michael Burns - Contextual Medical Visualization

Michael Burns - Contextual Medical Visualization

VisualizationMaterial importance defined within transfer functionImportant materials emphasized through shadingView-dependent cutaway structure determines

occlusion of object-of-interestMaterials removed in occluding areas, according to

their importance

ApplicationVisualize ultrasound data within CT scan for needle

driven operationsInitial feedback has been positiveCurrently being evaluated for clinical use

Michael Burns - Contextual Medical Visualization

Gianluca PaladiniSiemens Corporate Research

Adam FinkelsteinPrinceton University

Paper reviewers EuroVis 2007 hosts

Michael Burns - Contextual Medical Visualization