1 improved techniques for fast sliding thin-slab volume visualization janice z turlington*, william...
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Improved Techniques for
Fast Sliding Thin-Slab
Volume VisualizationJanice Z Turlington*, William E. Higgins*** Electrical Engineering, **The BioEngineering Program,
and *Computer Science and EngineeringThe Pennsylvania State University, University Park, PA 16802
SPIE Medical Imaging 2000, San Diego CA, 13 February
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Motivation Locate small structures in 3D CT volume
ObjectivesShow “true” information
Confident results for professional use
Fast techniques for real-time use
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Existing Visualization Techniques
projection imaging1
curved-section reformatting3
volume/surface rendering4multi-planar reconstruction2
virtual endoscopic rendering5
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Existing Limitationsdependence on a priori knowledge
voxel intensity decisions
partial-volume artifacts
voxel boundaries1{Hohne87,Napel92}
2{Robb1988,Remy96,McGuinness97}3{Robb1988,Hara96,Ramaswamy99}
4{Ney90,Drebin88,Tiede90} 5{Vining94,Ramaswamy99}
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Sliding Thin-Slab Visualization
improve understanding of lung changes
more precise characterization of distribution changes{Remy-Jardin et al. 96}
{Napel 92}(STS-MIP)
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Our New STS Techniques
fast general-purpose algorithms
dynamic sequence visualization
accurate 3D impression
slab change volume evolution
Depth-Weighted Maximum (DWmax)(DWmax)Extreme Gradient (EG)
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volume window column point slab
Sliding Thin-Slab Movement
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Fast STS Algorithmstemporal coherence1
adjacent views change little
only 2 slices differ
slabi window calculations apply to slab i+1
1{Ramaswamy1999}
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Depth-Weighted Maximum (DWmax)
wi = (depth of view – distancei from base)
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Depth-Weighting: 1D process
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sub-
volume
DWmax Algorithmsvolume
column
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STS-MIP
DWmax
{Turlington 2000}{Napel 1992}
CT image slice
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DWmax: Transverse Sequence Viewss=28
s=43 s=49
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DWmax: coronal detail
coronal sequence viewssingle sliceprojection image
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DWmax: sagittal detail
base slice
base slice
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Extreme Gradient (EG)Mapping of max tissue-density changes in slab
s(x,y) = max x,y{ } – max x,y{ }
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sub-
volume
volume
column
EG Algorithms
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small change
large change
moderate change
Extreme Gradient
EG not windowed
• image extremes• structure size• slab size
Function of:
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Endoluminal Border Detection
merging DWmax and EG
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Computation Gains of New Techniques
inversely proportionally to slab-size (ds)
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Current Reconstruction Techniques
cross-sectional imaging is CT gold standard
axial images alone enable remarkably accurate assessment
true paradigm shift requires comparison to traditional methods
{Naidich et al. 97}
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lymph node
detection
S=39
currently under development
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lymph node?
EG: soft tissue
EG: high density
DWmax
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Conclusion: New Techniquesfast, real-time
small structures visible
depth perception
true information
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My thanks to:Dr. William E. Higgins
The Whitaker FoundationDr. K. Kirk ShungDr. Cheng Dong
My Father
“For nothing is hidden, except to be revealed;nor has been secret, but that it should come to light.”
Mark 4:22
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2:40 pm Today…California Room
A. J. Sherbondy
Virtual Bronchoscopic ApproachCombining 3D CT and Endoscopic Video
Physiology and Functions from Multidimensional ImagesConference 3978
5:30 to 7:30 pm Today…California Room
G. McLennan
The Place of Virtual Bronchoscopy in Clinical Practice: Barriers and
SolutionsPhysiology and Functions from Multidimensional Images
Conference 3978
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DWmax errorNOT visible
Occurs in less than 2%of pointsmust occur simultaneously:1. closer to base than voxel of previous slab’s max2. depth-weighted voxel must differ:
< 5.5% of 16-bit previous-slab point (=0.7% 8-bit)
if error occurs: errror < 5 HU (16-bit) or 0 HU (8-bit)