Autonomous Direct Autonomous Direct 3D Segmentation of 3D Segmentation of Articular Knee CartilageArticular Knee Cartilage

Author :Enrico Hinrichs, Brian C. Lovell, Ben Appleton, Graham John

GallowaySource :Australian and New Zealand Intelligent Information Systems, 10-12 December 1(1), pages 417-420, SydneySpeaker : Ren-LI ShenAdvisor : Ku-Yaw Chang

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OutlineIntroductionSegmentation Discussion and results

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IntroductionIntroductionOsteoarthritis (OA) occurs

◦30 to 70 years◦Years<30:High-impact sports player

Using MRI ◦High-contrast cartilage images

Focus on ◦Automation segmentation◦Improvement accuracy of cartilage

measurements

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IntroductionIntroductionExpected outcomes

◦Autonomous segmentation method ◦Early detection of Pathology-

Associated Changes◦Detection of early onset OA

Problem◦Can’t use only grey level features

Similar cartilage contact zones Between the femoral and tibia cartilage

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IntroductionIntroduction

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IntroductionIntroductionSolution of these drawbacks is

the main objective of this work◦Develop a fully automated 3D

segmentation◦Non-linear diffusion(NLD)

Cartilage lesion classification system by Outerbridge

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IntroductionIntroduction

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OutlineIntroductionSegmentation Discussion and results

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SegmentationSegmentationPrevious work: B-Spline snakesDevelop a fully automated segmentation

method◦Using NLD and level sets

Articular cartilage is difficult to segment◦It is a thin structure (1-2mm)

Another difficulty◦Cannot be used to reliably cartilage

degeneration Multispectral Segmentation

Manual Segmentation9

SegmentationSegmentationNon-Linear Diffusion

◦Overcome meaningful details are removed as less important details

◦Enables image simplification◦Preserves large intensity

discontinuities and sharpens the edges of objects

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SegmentationSegmentationNon-Linear Diffusion

I is the image at time t and c is the diffusivity function

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SegmentationSegmentationAlgorithm Development Using 3D

Level Sets◦Cartilage surface S is represented in

space R3

◦Three dimensional level set function φ maps to one dimension R

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SegmentationSegmentationMatch the cartilage contour as a

partial differential level set equation

|∇φ | describes the normal velocity of the surface

F defined range of surface deformations

◦ Match the cartilage contour

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OutlineIntroductionSegmentation Discussion and results

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Discussion and resultsDiscussion and resultsAutomatic segmentation

◦Speed up drug development◦Improve OA medication

The algorithm development is currently in the initial phase and more results will be provided soon

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