blood vessel modeling using 2d/3d level set method
Post on 13-Dec-2015
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Blood Vessel Modeling using2D/3D Level Set Method
Overview
Main Idea Big Picture Problem Considered Motivation Main Approach : Level-Set Based 2D Segmentation
Discussion Strength and Weakness of the Approach Comparison with other approaches Future Direction
Pipeline for Blood Flow Modeling
3D Image Acquisition
Geometric Modeling
Finite ElementCalculation
Quantification,Visualization
cardivascular disease research, medical device design, and surgical planning
What is Problem?
Construct accurate patient-specific 3D geometric models (tetrahedral mesh) of blood vessels of interest
Why is it important?
Flow calculation using finite element method requires quality mesh
Accuracy of calculation depends on that of geometric model
Geometry Quantification
from Image to GeomtryWhy is it difficult ? Usually requires ill-defined segmentation process
Computers easily make an error Thresholding (Isocontouring) is well defined but often it is not useful in
medical applications Noisy Scanning
Accurate Construction
Patient-Specific
Operator Dependence Minimal user interaction is favorable
Robustness Always guarantee quality result ?
Main Approach for Geometry Path (Centerline) Construction
Semi-automatic , manual
2D image Segmentation
Surface Reconstruction thru lofting
Solid Model Operation (CSG) : Union
Automatic Mesh Generation
Level Set Method for 2D Segmentation
Implicit Geometry Description (X) = 0 ex) x,y,z) = x + y + z -1 = 0
Evolving Geometry : (X,t)=0 t + v | grad = 0 Intuitively, move a lot on low intensity gradient area and move little on
high intensity gradient area along normal direction v : speed function , k : curvature , I : intensity
Segmentation Quality Measurement Compare segmentation with phantom geometry
2 2 2
Surface Reconstruction Lofting
Multiple Vessels - Boolean Set Operation (Union)
Automatic Mesh Generation from solid models
3D Level Set Method
Extend 2D to 3D No centerline necessary No lofting (interpolation) : more accurate Smooth Junction Often Hard to control (geometry & topology)
2D level set approach
Strength Intuitive : taking
advantage of tubular shape of vessels
Clean Output Controllability
Geometry Topology
Noise Removal Robust
Weakness Heavy manual work
Centerline construction A bunch of 2D segmentation
which is not automatic Stopping criteria
Inaccurate Lofting & interpolation
Non-smooth junction Possible Self-Intersection Limited to only tubular
structure segmentation
Comparison
2D
Segmentation
3D
Segmentation
Control Good Bad
Noise Tolerance Good Bad
Robustness Good Bad
Accuracy Bad Good
User Dependence Bad Good
Smoothness Good/Bad Good/Bad
Conclusion
Image Based Vascular Model Construction Centerline construction Level set based 2D segmentation along centerline Surface reconstruction thru lofting Solid modeling & mesh generation
Tradeoffs : 2D vs 3D segmentation
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