Mammography and DICOM by vlIU99k7

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									Mammography and DICOM

  Adapting an Analog Modality
      to the Digital World

           Julian Marshall
         R2 Technology, Inc.
              Mammography
• Mammography is a film-based modality
  – Worldwide mammo machines:
     • 25,500 film-screen   98.1 %
     • 500 digital           1.9 %
       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
             Digitized Film
• Mammograms are digitized   RCC

                                   FILM
  – Wide variation
  – Scanners vary:
     • Resolution
     • Maximum O.D.                 SCANNER
     • Noise

                             RCC

                                   IMAGE
       Digital Mammography
• Mammograms are acquired digitally
  – Detectors do still vary:
     • Resolution
     • Bit depth (CR)
     • Noise (CR)



                               RCC

                                     IMAGE
              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%
              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!
    Mammography and PACS
• Images are recalled regularly
• Scheduled pre-fetching is easy
• But … each image is accessed each year!

               1998                    2000                  2002
          RCC                   RCC                   RCC
           RCC                   RCC                   RCC
             RCC                   RCC                   RCC
              RCC                   RCC                   RCC
                RCC                   RCC                   RCC
                 RCC                   RCC                   RCC
                   RCC                   RCC                   RCC
                    RCC                   RCC                   RCC
                      RCC                   RCC                   RCC
                       RCC                   RCC                   RCC
                         RCC                   RCC                   RCC
                          RCC                   RCC                   RCC
    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
    Computer-Aided Detection
• Simple example: Count the ‘F’s


     FINISHED FILES ARE THE RE-
     SULT OF YEARS OF SCIENTIF-
     IC STUDY COMBINED WITH
     THE EXPERIENCE OF YEARS
    Computer-Aided Detection
• Most people find these three


     FINISHED FILES ARE THE RE-
     SULT OF YEARS OF SCIENTIF-
     IC STUDY COMBINED WITH
     THE EXPERIENCE OF YEARS
    Computer-Aided Detection
• Many people do not find all six!


     FINISHED FILES ARE THE RE-
     SULT OF YEARS OF SCIENTIF-
     IC STUDY COMBINED WITH
     THE EXPERIENCE OF YEARS
    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
           DICOM WG 15
• Standards development:
  – Digital X-ray (includes mammo)   1998
  – Mammography CAD SR               2001
     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
     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
                          Inference Tree
         Ov e rall
     Impre ssion /
Re comme ndation
                                   O
                                                             Individual Calcification:
                                                                                  O    Ov erall


                                                                     –Location of center
                                                                                  I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                –Outline of individual calcification
                                                                                  SP   Related Spatially
Re comme ndation
                                                                     –Size        T    Related Temporally


      Composite
         Obje ct                           SP                T                    CL   Related Contra-Laterally



                                                                                  C    Indiv idual Calcification



      Composite                                                                   CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                                  D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Three individual calcifications are detected in a single image
                          Inference Tree
         Ov e rall
     Impre ssion /
Re comme ndation
                                   O
                                                             Calcification cluster:
                                                                                  O    Ov erall


                                                                     –Location of center
                                                                                  I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                –Outline of cluster
                                                                                  SP   Related Spatially
Re comme ndation
                                                                     –Size        T    Related Temporally


      Composite
                                                                     –No. of individual calcifications
         Obje ct                           SP                T                    CL   Related Contra-Laterally



                                                                                  C    Indiv idual Calcification



      Composite                                                                   CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                                  D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



The three are grouped together as a cluster of calcifications
                          Inference Tree
         Ov e rall
     Impre ssion /
Re comme ndation
                                   O
                                                             Density             O    Ov erall


                                                                     –Center of density
                                                                                 I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                –Outline    SP   Related Spatially
Re comme ndation
                                                                     –Size       T    Related Temporally


      Composite
                                                                     –Description of margin
         Obje ct                           SP                T                   CL   Related Contra-Laterally



                                                                                 C    Indiv idual Calcification



      Composite                                                                  CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                                 D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Densities and other clusters are detected, some from priors
                          Inference Tree
         Ov e rall
     Impre ssion /                 O
Re comme ndation                                                              O    Ov erall



                                                                              I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                         SP   Related Spatially
Re comme ndation

                                                                              T    Related Temporally


      Composite
         Obje ct                           SP                T                CL   Related Contra-Laterally



                                                                              C    Indiv idual Calcification



      Composite                                                               CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                              D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Densities become masses if spatially related
                          Inference Tree
         Ov e rall
     Impre ssion /                 O
Re comme ndation                                                              O    Ov erall



                                                                              I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                         SP   Related Spatially
Re comme ndation

                                                                              T    Related Temporally


      Composite
         Obje ct                           SP                T                CL   Related Contra-Laterally



                                                                              C    Indiv idual Calcification



      Composite                                                               CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                              D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Other findings may also be spatially related
                          Inference Tree
         Ov e rall
     Impre ssion /                 O
Re comme ndation                                                              O    Ov erall



                                                                              I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                         SP   Related Spatially
Re comme ndation

                                                                              T    Related Temporally


      Composite
         Obje ct                           SP                T                CL   Related Contra-Laterally



                                                                              C    Indiv idual Calcification



      Composite                                                               CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                              D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Calcs within a mass are related spatially
                          Inference Tree
         Ov e rall
     Impre ssion /                 O
Re comme ndation                                                              O    Ov erall



                                                                              I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                         SP   Related Spatially
Re comme ndation

                                                                              T    Related Temporally


      Composite
         Obje ct                           SP                T                CL   Related Contra-Laterally



                                                                              C    Indiv idual Calcification



      Composite                                                               CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                              D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Objects found in priors are temporally related to currents
                          Inference Tree
         Ov e rall
     Impre ssion /                 O
Re comme ndation                                                              O    Ov erall



                                                                              I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                         SP   Related Spatially
Re comme ndation

                                                                              T    Related Temporally


      Composite
         Obje ct                           SP                T                CL   Related Contra-Laterally



                                                                              C    Indiv idual Calcification



      Composite                                                               CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                              D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Objects can also be related contra-laterally (not shown here)
                          Inference Tree
         Ov e rall
     Impre ssion /                 O
Re comme ndation                                                              O    Ov erall



                                                                              I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                         SP   Related Spatially
Re comme ndation

                                                                              T    Related Temporally


      Composite
         Obje ct                           SP                T                CL   Related Contra-Laterally



                                                                              C    Indiv idual Calcification



      Composite                                                               CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                              D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Individual Impressions and Recommendations are formed
                          Inference Tree
         Ov e rall
     Impre ssion /                 O
Re comme ndation                                                              O    Ov erall



                                                                              I    Indiv idual

       Indiv idual
     Impre ssion /   I                              I                         SP   Related Spatially
Re comme ndation

                                                                              T    Related Temporally


      Composite
         Obje ct                           SP                T                CL   Related Contra-Laterally



                                                                              C    Indiv idual Calcification



      Composite                                                               CC   Calcification Cluster
         Obje ct              SP                    SP               SP

                                                                              D    Density



          Single
          Image      D   CC        CC           D        D       D        D
         Finding




          Single
          Image          C             C        C
         Finding



Overall Impression and Recommendation is formed
    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.
            Other Information
•   Breast outline (border)
•   Pectoral muscle outline
•   Nipple location
•   Other findings:
    – BBs
    – J-wires
          Other Information
• Image quality findings
  – Motion blur
  – Artifacts
             Coming Soon
• Breast Imaging Report      SR
• Relevant Patient History   Query
               Summary
• Mammography is almost entirely a film-
  based modality
• Slowly this is changing
• And with that change comes DICOM!

								
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