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Mammography. Mammography is a film-based modalityWorldwide mammo machines:25,500 film-screen500 digital. 98.1 % 1.9 %. Reading Mammograms. ACR position:Radiologist must read original imageUS clinical practice:Read film-screen mammograms on filmDo not digitize films and read softcopyPriors
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1. Mammography and DICOM Adapting an Analog Modality
to the Digital World
Julian Marshall
R2 Technology, Inc.
2. Mammography Mammography is a film-based modality
Worldwide mammo machines:
25,500 film-screen
500 digital
3. Reading Mammograms ACR position:
Radiologist must read original image
US clinical practice:
Read film-screen mammograms on film
Do not digitize films and read softcopy
Priors can be read softcopy
4. Digitized Film Mammograms are digitized
Wide variation
Scanners vary:
Resolution
Maximum O.D.
Noise
5. Digital Mammography Mammograms are acquired digitally
Detectors do still vary:
Resolution
Bit depth (CR)
Noise (CR)
6. Mammography Imaging demands are extreme:
Typical resolutions:
Film: 43 to 50 microns x 12 bits
Digital: 50 to 100 microns x 14 bits
Typical image sizes:
18x24 cm 85%
24x30 cm 15%
7. Mammography Imaging demands are extreme:
Typical data volume:
4 film case: 180 MB avg
100 case/day: 18.0 GB/day
250 days/yr: 4.5 TB/year
Film scanner will generate:
45 MB per minute, all day long!
8. Mammography and PACS Images are recalled regularly
Scheduled pre-fetching is easy
But … each image is accessed each year!
9. Computer-Aided Detection Use a computer to look for regions-of-interest that might be overlooked by a radiologist
Simple example: Count the ‘F’s
10. Computer-Aided Detection Simple example: Count the ‘F’s
11. Computer-Aided Detection Most people find these three
12. Computer-Aided Detection Many people do not find all six!
13. Computer-Aided Detection Mammography CAD first became available:
1998 Film-screen mammography
2000 Digital mammography
At that time:
DICOM support for images
No DICOM support for CAD output
14. DICOM WG 15 Standards development:
Digital X-ray (includes mammo) 1998
Mammography CAD SR 2001
15. Mammography CAD SR Allows encoding of ACR’s BI-RADSTM reporting structure via an inference tree
“Simple” CAD devices can create “simple” Mammo CAD objects
“Complex” CAD devices can create full mammography report inference tree
16. Mammography CAD SR Single image finding – found in one image
Composite object – findings correlated in one or more images:
Temporal – comparison over time
Spatial – e.g. mass behind the nipple, or mammo/ultrasound correlation
Contra-laterally – e.g. left/right comparison
17. Inference Tree
18. Inference Tree
19. Inference Tree
20. Inference Tree
21. Inference Tree
22. Inference Tree
23. Inference Tree
24. Inference Tree
25. Inference Tree
26. Inference Tree
27. A Vast Array of Adjectives Every Single Image Finding and Composite Object has a set of common descriptors:
Rendering intent
Certainty of finding
Probability of cancer
Plus a variety of context-specific descriptors:
Calcs: rod-like, pleomorphic, etc.
28. Other Information Breast outline (border)
Pectoral muscle outline
Nipple location
Other findings:
BBs
J-wires
29. Other Information Image quality findings
Motion blur
Artifacts
30. Coming Soon Breast Imaging Report SR
Relevant Patient History Query
31. Summary Mammography is almost entirely a film-based modality
Slowly this is changing
And with that change comes DICOM!