Volume Rendering for Virtual Colonoscopy on an Affordable PC

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Volume Rendering for Virtual Colonoscopy on an
Affordable PC

• Kevin Kreeger
• Department of Computer Science

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• Department of Computer Science
• Frank Dachille, Michael Wan, Ingmar Bitter,
• Li Wei, Arie Kaufman
• Department of Radiology
• Mark Wax and Jerome Liang

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Surface Rendering Artifacts
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Surface Rendering Artifacts
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Surface Rendering Volume Rendering
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Translucent Rendering

• Viewing within the structure
• Stool ball confirmation

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Why Not Volume Rendering?

• 512 ? 512 ? 400 ? 2 Bytes 200 MB
• For over 10 frames per second
• High end Multi-Processor Workstation
• For affordable machine
• Less than 1 frame per second
• Cine-loop movie no interactivity

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Stony Brook Volume Rendering

• 15 Years of Volume Rendering
• Breakthrough Algorithms
• Hardware Acceleration Cards
• PC Platform

Navigation
Analysis Tools
Virtual Colonoscopy Application
Application
Volume Rendering Code
Graphics Library
System/ Hardware
Graphics/Rendering Card
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Volume Rendering Requirements(for Virtual
Colonoscopy)

• High quality lighting
• Shadows
• Reflected light
• Full RGB color
• Better depth perception
• Translucency
• 10 FPS for interactivity

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Test Setup

• Workstation vs. PC
• 12 Processors on SGI Challenge with Infinite
  Reality graphics
• PC with commercially available high end graphics
  /rendering hardware
• 10 patient datasets
• Guided interactive navigation

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Qualitative Tests

• Side-by-Side Image Compare
• 8 colon segments
• cecum, ascending, hepatic flexure, transverse,
• splenic flexure, descending, sigmoid and
  rectum
• 80 image pairs
• 1-10 scale
• Artifacts
• Smoothness
• Contrast/Texture
• Sharpness
• Diagnostic Capability

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Quantitative Tests

• Raw frame rate
• End-to-end guided navigation time
• Automatic centerpath following
• Interactive examination

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Qualitative Results Image Artifacts
Ave. PC(8.9) vs. SGI(9)
PC (9)
SGI (9)
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Qualitative Results Image Artifacts
Ave. PC(8.9) vs. SGI(9)
PC (8)
SGI (9)
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Qualitative Results Smoothness
Ave. PC(9) vs. SGI(9)
PC (9)
SGI (9)
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Qualitative Results Contrast/Texture
Ave. PC(8.9) vs. SGI(9)
PC (9)
SGI (9)
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Qualitative Results Contrast/Texture
Ave. PC(8.9) vs. SGI(9)
PC (8)
SGI (9)
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Qualitative Results Sharpness
Ave. PC(8.3) vs. SGI(9)
PC (9)
SGI (9)
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Qualitative Results Sharpness
Ave. PC(8.3) vs. SGI(9)
PC (7)
SGI (9)
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Conclusions

• Equal Diagnostic capability of SGI vs. PC
• Pooled Variance t-tests showed no significant
  difference in any qualitative feature
• Average frames per second
• 9.2 (SGI) vs. 9.1 (PC)
• Average navigation time
• 8.8 min (SGI) vs. 9.0 min (PC)

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ADVANCING VIRTUAL COLONOSCOPY TO PRACTICE
Thank You