1. Consistent Presentation of Images
Lawrence Tarbox, Ph.D.
Washington University in St. Louis

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

3. 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

4. Problems of Inconsistency
0.5
1.5
1.0
3.0
Not all display levels are perceivable on all devices
Slide Provided by David Clunie, Quintiles Intelligent Imaging

5. Problems of Inconsistency
Laser Printer
Digital Modality
Printed images don’t look like displayed images
Slide Provided by David Clunie, Quintiles Intelligent Imaging

6. Grayscale Standard Display Function
.01 .1 1 10
100
1000
200
400
600
800
Grayscale Standard Display Function
JND Index
Same number of Just Noticeable Difference == Same perceived contrast
Despite different change
in absolute luminance
Slide Provided by David Clunie, Quintiles Intelligent Imaging

7. Display Calibration Tools (Photometer)
Slide Provided by Jerry Gaskill, Image Smiths Inc.

8. Monitor Characteristic Curve
Luminance
100 10
0.1
Ambient Light
0.01 50
100
150
200
250
300
Digital Driving Level
Slide Provided by David Clunie, Quintiles Intelligent Imaging

9. Perceptual linear device - LUT
Mapping P-Values to Input of Characteristic Curve (DDL’s) 50
100
150
200
250
300
P-Values
DDL
Slide Provided by David Clunie, Quintiles Intelligent Imaging

10. Grayscale Standard Display Function
.01 .1 1 10
100
1000
200
400
600
800
Grayscale Standard Display Function
JND Index
Same number of Just Noticeable Difference == Same perceived contrast
Despite different change
in absolute luminance
Slide Provided by David Clunie, Quintiles Intelligent Imaging

11. Distributed Image Consistency
Laser Printer
Digital Modality
Identical perceived contrast
Workstation
Workstation

12. DICOM Grayscale Image Transformation ModelV O I L U ( S u b c ) M k d l y A g e h p D .
Presentation
LUT
Transformation
Window/Level
or VOI LUT
Rescale Slope/Intercept
or Modality LUT
Original
Image
Display
P-Values
Grayscale Transformations
Shutter, Annotation and Spatial Transformations
Presentation LUT shape : IDENTITY, INVERSE 10

13. Spatial Transformations
Entire Image Selected
Flip Horizontal
Scale To Fit
Original Image
Transformed Image

14. Spatial Transformations
Part of Image Selected
Flip Horizontal
Scale To Fit
Original Image
Transformed Image

15. Transformation & Annotation
Part of Image Selected
Flip Horizontal
Scale To Fit
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

16. Distributed Image Consistency
Printer
Digital Modality
Different perceived color
Workstation
Workstation

17. Distributed Image Consistency
Printer
Digital Modality
Identical perceived color
Workstation
Workstation

18. 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

19. DICOM Grayscale Image Transformation ModelV O I L U ( S u b c ) M k d l y A g e h p D .
Presentation
LUT
Transformation
Window/Level
or VOI LUT
Rescale Slope/Intercept
or Modality LUT
Original
Image
Display
P-Values
Grayscale Transformations
Shutter, Annotation and Spatial Transformations
Presentation LUT shape : IDENTITY, INVERSE 10

20. Grayscale & Color Pipeline

21. Blending for CT-PET
select underlying
select superimposed

22. Blending for CT-PET
select underlying
[register]
select superimposed

23. Blending for CT-PET select underlying [register] select superimposed
resample

24. Blending for CT-PET select underlying [register] within slices
select superimposed
resample

25. Blending for CT-PET select underlying [register] within slices
select superimposed
resample
[between slices]

26. Blending for CT-PET select underlying rescale and window [register]
within slices
select superimposed
resample
[between slices]

27. Blending for CT-PET select underlying rescale and window [register]
within slices
select superimposed
resample
pseudo-color
[between slices]

28. Blending for CT-PET select underlying rescale and window [register]
within slices
select superimposed
resample
pseudo-color
[between slices]

29. 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)

30. Hanging Protocols

31. 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 patient’s images
Hence a protocol, not a presentation state

32. Hanging Protocols New Study Old Lateral New Frontal Townes L F
Old Study

33. 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