Consistent Presentation of Images

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Consistent Presentation of Images

• Lawrence Tarbox, Ph.D.
• Washington University in St. Louis

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Overview

• Review of Grayscale Presentation State
• Color Presentation States
• Color Consistency
• Presentation States applied to Color Images
• Color Blending - CT-PET fusion
• Hanging Protocols

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Problems of Inconsistency

• VOI chosen on one display device
• Rendered on another with different display
• Mass expected to be seen is no longer seen

mass visible
mass invisible
Slide Provided by David Clunie, Quintiles
Intelligent Imaging
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Problems of Inconsistency
Slide Provided by David Clunie, Quintiles
Intelligent Imaging
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Problems of Inconsistency

• Printed images dont looklike displayed images

Slide Provided by David Clunie, Quintiles
Intelligent Imaging
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Grayscale Standard Display Function
Slide Provided by David Clunie, Quintiles
Intelligent Imaging
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Display Calibration Tools (Photometer)
Slide Provided by Jerry Gaskill, Image Smiths Inc.
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Monitor Characteristic Curve
Monitor Characteristic Curve
Luminance
100
10
0.1
Ambient Light
0.01
0
50
100
150
200
250
300
Digital Driving Level
Slide Provided by David Clunie, Quintiles
Intelligent Imaging
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Perceptual linear device - LUT
Slide Provided by David Clunie, Quintiles
Intelligent Imaging
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Grayscale Standard Display Function
Slide Provided by David Clunie, Quintiles
Intelligent Imaging
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Distributed Image Consistency
Identical perceived contrast
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DICOM Grayscale Image Transformation Model
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Spatial Transformations
Entire Image Selected
Scale To Fit
Flip Horizontal
Original Image
Transformed Image
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Spatial Transformations
Part of Image Selected
Scale To Fit
Flip Horizontal
Original Image
Transformed Image
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Transformation Annotation
Part of Image Selected
Scale To Fit
Flip Horizontal
Mass behind heart
Mass behind heart
Original Image
Transformed Image
In this example, - text annotation is specified
by image relative visible anchor point - the
circle is a separate image relative graphic
annotation
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Distributed Image Consistency
Different perceived color
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Distributed Image Consistency
Identical perceived color
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Standard Color Space

• GSDF filled a void
• Color consistency already standardized
• ICC - International Color Consortium
• Graphics and pre-press industry
• CIE Colorimetry
• Profiles of input and output devices
• COTS color management software handles conversion
• Perceptual rendering intent

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DICOM Grayscale Image Transformation Model
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Grayscale Color Pipeline
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Blending for CT-PET
selectunderlying
selectsuperimposed
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Blending for CT-PET
selectunderlying
register
selectsuperimposed
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Blending for CT-PET
selectunderlying
register
selectsuperimposed
resample
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Blending for CT-PET
selectunderlying
register
within slices
selectsuperimposed
resample
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Blending for CT-PET
selectunderlying
register
within slices
selectsuperimposed
resample
between slices
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Blending for CT-PET
selectunderlying
rescale andwindow
register
within slices
selectsuperimposed
resample
between slices
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Blending for CT-PET
selectunderlying
rescale andwindow
register
within slices
selectsuperimposed
pseudo-color
resample
between slices
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Blending for CT-PET
selectunderlying
rescale andwindow
blend
register
within slices
selectsuperimposed
pseudo-color
resample
between slices
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Three New SOP Classes

• Color Presentation State
• Pseudo-Color Presentation State
• Blending Presentation State
• ICC Profile
• Defines output of all color presentation states
• Optionally present in all color images
• PCS-Values (analogous to grayscale P-Values)
• Profile Connection Space (CIELAB or CIEXYZ)

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Hanging Protocols
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Hanging Protocols

• Default display protocols
• A set of instructions
• How to layout a class of images for display
• Order, orientation, windowing, processing
• Not specific to a particular patients images
• Hence a protocol, not a presentation state

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Hanging Protocols
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Using a Hanging Protocol

• Given a current exam (e.g. reading worklist)
• Find potentially applicable protocols
• Retrieve them from archive
• Select one from those available
• Select image /- other studies to which it
  applies
• Display selected images as instructed