ii - ufrgs medical images visualization at the computer graphics group/ufrgs carla maria dal sasso...

II - UFRGS

Medical Images Visualization at the Medical Images Visualization at the

Computer Graphics Group/UFRGSComputer Graphics Group/UFRGS

Carla Maria Dal Sasso Freitas

February, 2000

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SummarySummary

1. Introduction

3. CG Group overviewPrevious works

4. Current project: VPat

5. Final comments

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1. 1. IntroductionIntroduction

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Porto Alegre

470,25 km2

Population: ~ 1,286.251

Climate: Subtropical wet with four well-defined seasons

1. 1. IntroductionIntroduction

Higher education: 4 large universities (each one with more than 20K students) and several small colleges

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UFRGS (Federal University of Rio Grande do Sul)• Created in 1895• One of the top five universities in Brazil, both in size and

quality• ~ 2,278 faculty members• Students: ~ 25,286 (undergraduate and graduate)

1. Introduction1. Introduction

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Informatics Institute

Teaching and research since 1968

Established as an Institute in 1989

Departments• Applied Computing• Theoretical Computing


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Faculty• 69 professors (INPG, Grenoble; Karslruhe and Stuttgart,

Germany; Newcastle, UK; Stanford, USA; Coimbra, Portugal; Louvain, Belgium; Amsterdam, Netherlands; ...)

• Students: 700 undergraduate level + 270 graduate level

Courses at graduate level• M.Sc. in Computer Science

• Ph.D. in Computer Science

• Professional education


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Research areas• Computer Graphics and Image processing

• Computer Architecture/Parallel Processing

• Microelectronics/Digital Systems

• Data Base Systems

• Fault Tolerance

• Software Engineering

• Theoretical Computer Science

• Artificial Intelligence

• Computational Mathematics

• Computer Networks/Communication

• Formal Methods


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2. 2. CG Group OverviewCG Group Overview

Started in 1978, with one professor only

People4 Professors

1 Post-doc

5 Ph.D. Students

18 M.Sc. Students

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Research in the 80's: CAD

Research in the 90's

Rendering and animation

Scientific visualization • Meteorological data• Geological data• Medical images

Image processing techniques

2. CG Group Overview2. CG Group Overview

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Previous works regarding medical images

Nedel at EPFL

Freitas and group at UFRGS


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Previous works

Nedel at EPFL

Freitas and group at UFRGS


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3. 3. VPat (VPat (Visualization and interaction with Virtual PatientsVisualization and interaction with Virtual Patients))

Generation of virtual human models (virtual patients) to use in medical applications such as simulation of surgery and training

Movement simulation

Development of a framework to guarantee software reuse

Integration of the existing tools

Goals

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Activities

Design of the OO framework

Volume visualization

3D reconstruction of the human parts from real data

Motion simulation and body deformation (anatomic simulation of human bodies)

3. VPat3. VPat

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Activities


Volume visualization• RenderVox improvement and conversion to the VPat

framework

• Survey about collaborative visualization

• Multimodal visualization


Motion simulation and body deformation (anatomic simulation of human bodies

3. VPat3. VPat

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Multimodal visualization with RenderVox • MRI and PET data obtained from different patients, no

registration algorithm used

(Marcelo Silva, 2000)

3. VPat3. VPat

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Multimodal visualization: ongoing work• Data obtained from the same patient• Cooperation with the best hospital in Brazil

~ INCOR/University of Sao Paulo

• Study of registration methods

(Isabel Manssour’s PhD thesis)

3. VPat3. VPat

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Activities



3D reconstruction of the human parts from real data• Marching cubes implementation

• Study of multi-resolution techniques


3. VPat3. VPat

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Activities




Motion simulation and body deformation (anatomic simulation of human bodies)• Mechanical modeling of joints

• Skeleton motion control

• Soft tissue deformation

3. VPat3. VPat

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Surgery simulation

(Luciana Nedel, 1999)

3. VPat3. VPat

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Activities





3. VPat3. VPat

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4. 4. Final commentsFinal comments

Interactive segmentation of medical images

• Olabarriaga, 1999 with A. Smeulders, Amsterdam

Development of new filtering techniques

• Scharcanski & Jung, 1999/2000

~ultrasound images from fetal hearts

~mammographic images

Related works in our group

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http://www.inf.ufrgs.br/cghttp://www.inf.ufrgs.br/cg

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Goal: Medical data visualization overview

• Different approaches for collaborative visualization

• To get knowledge about difficulties for its utilization

(WSCG 2000, February 7-11, Plzen)(WSCG 2000, February 7-11, Plzen)Collaborative Visualization in MedicineCollaborative Visualization in Medicine

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Collaborative Visualization in MedicineCollaborative Visualization in Medicine

CSCW (Computer Support for Cooperative Work)• New successful area

• People in different places working together

CSCV (Computer Support for Collaborative Visualization)• Subset of CSCW applications

• Shared visualization and control parameters

• Challenge: multi-user interactive applications

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Visualization pipeline (Haber & McNabb, 1990) extension to achieve collaboration


Shared Control Shared Data

Filtering(F) Mapping(M) Render(R)

Image

Data

Filtering(F) Mapping(M) Render(R)

Image

Data

User A

User B

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Collaborative visualization systems applied to Medicine• Image presentation to remote collaborators

• Image-based interaction


Telemedicine• Communication technology used to support

interaction between physicians and patients

• Applications~Remote clinical consultation~Telesurgery, teleradiology~Collaborative diagnosis

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TeleInViVo

• Fraunhofer Center for Computer Graphics, DARPA e MATMO

• Main goals~Therapy planning and

treatment~Medical training,

surgery and diagnosis


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TeleMed• Los Alamos National Laboratory and National Jewish Center

for Immunology and Respiratory Medicine

• Prototype of the Virtual Patient Records (VPR)


• Main goal~Standardize the

electronic management of patient information

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Current trend• Use of the Web as a collaboration environment

Challenges and open questions


• Communication technology

• Identification (security) handling

• Shared data coherence

• Synchronization of user activities

• User-friendly interface

• Real-time visualization and interaction

• VR devices accuracy and touch-feedback

• Realistic images

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The building of a collaborative system is an interdisciplinary effort• User-centered approach

• Efficient data management

• Object-oriented design and programming


Collaborative systems have to be improved to become attractive work tools

Several difficulties for the real utilization of such systems are still found

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Anatomic modeling of skeletons

Joints positionThe skeleton

( Luciana Nedel, 1998)

Nedel at EPFLNedel at EPFL (Ph.D. Thesis)(Ph.D. Thesis)

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Nedel at EPFLNedel at EPFL

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Simulation of the muscles action

Action lines

• Represent mechanically the force that a muscle produces on a bone

• Composed by an origin, an insertion and optionally by one or more control points



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Muscles deformation

Mass-spring deformation model

• Example: compression • Example: extension



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Example: reconstructed muscle



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Framework to allow the human body modeling and simulation

Body Builder Plus - integration tool

• Allows the design of human models created entirely with bones and reconstructed muscles

• Combines deformable muscles with metaballs representing some muscles, organs and fat tissues


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Body Builder Plus: examples...



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Interactive volume visualization of medical images using ray casting

Available toolsNavigation through the slices data set

Cutting planes

Cutting volume/ subvolume

Hybrid (geometric and volume) visualization

Multimodal visualization

RenderVoxRenderVox

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Camera control and slice visualization

Marcelo Silva, 1999

RenderVoxRenderVox

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Interactive interface

(Marcelo Silva, 1998/2000)

RenderVoxRenderVox

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MRI of a head


RenderVoxRenderVox

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Transparency levels using classification tables

RenderVoxRenderVox

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Cutting with planes

RenderVoxRenderVox

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Cutting with volumes

RenderVoxRenderVox

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Cutting with non-planar tools

Cutting with planes and volumes



RenderVoxRenderVox

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Hybrid rendering (geometric models & volume data)


RenderVoxRenderVox

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Visualization of layers 1 and 2 of characteristic “Marcos de Inundação”, grid dimension 30 x 30, layer 1 in wireframe

(Karen Basso, 1999)

GeoVisGeoVis

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Visualization of layer 1 of characteristic “Marcos de Inundação”, and “Isolita” attribute.

(Karen Basso, 1999)

GeoVisGeoVis

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Isocontour map for attribute “Percentualde Areia”, in layer 1 of “Marcos de Inundação”

(Karen Basso, 1999)

GeoVisGeoVis

ii - ufrgs medical images visualization at the computer graphics group/ufrgs carla maria dal sasso...

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