kongkuo lu and william e. higgins penn state university department of electrical engineering...
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Kongkuo Lu and William E. HigginsPenn State University
Department of Electrical EngineeringUniversity Park, PA 16802, USA
Improved 3D Live-Wire Method with Application to 3D CT Chest
Image Analysis
SPIE Medical Imaging 2006: Image Processing, San Diego, CA, 14 Feb. 2006.
Motivation
ROI segmentation is important, but difficult Manual slice tracing always works
--but it is time consuming Automated segmentation avoids user intervention
--but it is strongly application dependent Semiautomatic methods allow for full user control
while reducing human involvement
Prior Work
Mortensen et al. (IEEE Computers in Cardiology 1992) Mortensen et al. (Graphical Models and Medical Imaging 1998) Falcão et al. (SPIE Medical Imaging 1996) Falcão et al. (Graphical Models and Medical Imaging 1998)
2D Live Wire:2D Live Wire:
Falcão et al. (Medical Image Analysis 2000) Schenk et al. (MICCAI 2000) Salah et al. (Workshop Bildverarbeitung in der Medizin 2005) Hamarneh et al. (SPIE Medical Imaging 2005) König et al. (SPIE Medical Imaging 2005)
3D Live Wire:3D Live Wire:
Cost Function
Image Feature Cost
Laplacian Zero-Crossing
Gradient Magnitude
Gradient Direction
Secondary Gradient Direction
Zf
Df
Gf
),(),()()(),( qpfwqpfwqfwqfwqpl DfDfDDGGzz Cost Function:Cost Function:
DffNew New Cost!Cost!
* Three components were derived from Mortensen 98
Gradient Direction
)(1
),( 21
qpfDf
D(p)D(p)
D(r)D(r)pp
rr
|r-p||r-p|
D’(r)D’(r)
D’(p)D’(p)
1D(p)D(p)
D(r)D(r)
pprr
|r-p||r-p|2D’(r)D’(r)
D’(p)D’(p)
)(3
2),( 21
qpfDGradient Direction:
1
2
New Gradient Direction:
1
D(r)D(r)
pprr
|r-p||r-p|2D’(r)D’(r)
D’(p)D’(p)
2D Graph-Search Algorithm
2D graph-search algorithm for the live-wire method2D graph-search algorithm for the live-wire method
(Modified based on Mortensen 98)(Modified based on Mortensen 98)
2D Live Wire Introduction
292422181514481019
402820141311510511
33221920138483916
30242736292414127715
34293762393319131014
4429161320
2919171929
2523252947
33303541
* Derived from Mortensen 98
3D Live Wire
Trans.Trans.Sag.Sag.
Coro.Coro.
2D live wire on Sag. slice 12D live wire on Sag. slice 12D live wire on 2 Coro. slices2D live wire on 2 Coro. slices Running 3D live wire in Trans. Running 3D live wire in Trans. directiondirection
2D live wire on Sag. slice 22D live wire on Sag. slice 2 Generate seeds on every slice in Generate seeds on every slice in Trans. directionTrans. direction
3D Live Wire
Slice iSlice i
Slice i+1Slice i+1
Slice i-1Slice i-1
Slice i+2Slice i+2
Slice i-2Slice i-2
DistanceDistance
DistanceDistance
Reference SliceReference Slice
2D live wire on ref. slice2D live wire on ref. slice Proj. result onto neighbor slicesProj. result onto neighbor slices Define boundaries using 2D live wireDefine boundaries using 2D live wire Proj. results onto following slicesProj. results onto following slices
2D Live Wire Evaluation
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EOREOR
EOREOREEOOR
BB
BBRP
22
222
)()(1
jEOR
jEOREOR
GB
GBAC
nmj
nmjnmj
2
2
2
22
)()(1
Three Factors: (Three Factors: (derived from derived from Falcão98, 00)
Efficiency --Efficiency -- Processing time to segment an ROIProcessing time to segment an ROI
Repeatability --Repeatability --
Accuracy --Accuracy --
2D Live Wire Evaluation
Segmentation Reproducibilities
Inter-Operator Segmentation Reproducibilities
2D Live Wire Evaluation
R21 R22 R23
Efficiency 23.4s 13s 18.6s
Repeatability 97.86% 98.57% 98%
Accuracy 98.38% 98.76% 97.68%
Summary:Summary:
Time ratio between manual tracing and 2D live wire:Time ratio between manual tracing and 2D live wire:
R21 R22 R23
2D Live Wire 23.4s 13s 18.6s
Manual Slice Tracing 310s 192s 278s
Time Ratio 13.25 14.77 14.95
* Efficiency comparison based on accuracy higher than 95%
3D Live Wire Evaluation
R31 R32 R33
Efficiency 34s 95s 8m9sRepeatability 97.64% 97.88% 96.87%
Accuracy 98.08% 98.12% 97.16%
Summary:Summary:
Time ratio between 3D live wire and Time ratio between 3D live wire and 2D live wire / manual slice tracing:2D live wire / manual slice tracing:
R21 R22 R23
2D LW vs. 3D LW 7.2 8.4 9.9
Manual vs. 3D LW 28 56 41
* Efficiency comparison based on accuracy higher than 90%
Summary
Introduce new gradient direction cost 2D live wire works very well
2D Live Wire:2D Live Wire:
3D Live Wire:3D Live Wire:
Reliable and efficient