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Mammogram

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Mammogram, Mammography

  • Background
  1. Mammogram visualizes glandular tissue
  2. Lucent Areas
    1. Fat appears as dark, hazy gray areas
  3. White areas
    1. Parenchymal cells and ducts
    2. Breast tissue abnormalities
  • Protocol
  • Mammographic Views
  1. Preparation
    1. Breast compressed to 6 cm
      1. Skin taut
      2. More compression
        1. Uses less radiation
        2. Results in better image
  2. Standard Views
    1. Cranial caudal (C-C)
      1. Head to toe view
      2. Shows medial tissue with centered nipple
    2. Medial-Lateral Oblique (MLO)
      1. Side view including axilla
      2. Images more of Breast than C-C view
  3. Additional Views
    1. Cone down compression
      1. Indicated for Nodules
    2. Magnification
      1. Indicated for micro-calcifications
    3. Eklund View (Implant Displacement View)
      1. Indicated for Breast Implants
      2. Pushes Breast Implant out of image
      3. Compresses Breast to 3.5 cm
      4. Very umcomfortable for patient
  • Protocol
  • Technological enhancement
  1. Digital Mammography
    1. Overall diagnostic accuracy similar to XRay film
    2. Test Sensitivity better in specific cohorts
      1. Women younger than 50 and premenopausal women
      2. Radiographically dense Breasts
      3. Pisano (2005) N Engl J Med 353:1773-83 [PubMed]
  2. Computer-aided detection
    1. Test Sensitivity decreases with use
    2. Higher False Positive Rate
    3. No change in overall Breast Cancer detection rates
    4. Fenton (2007) N Engl J Med 356:1399-409 [PubMed]
  • Timing
  1. Perform during Follicular Phase (Days 1-14)
    1. Less Breast engorgement
  2. Age 40-49 years
    1. ACOG and AMA recommend every 1-2 years
    2. USPSTF Strength of Recommendation: C
    3. New data recommends every 18 month Mammograms
    4. Reference
      1. Bjurstam (1997) Cancer 80: 2091-9 [PubMed]
  3. Age 50 years and older
    1. Annual Mammogram
    2. USPSTF Strength of Recommendation: A
    3. Continue screening indefinitely as long as benefit
  • Efficacy
  1. Early detection of Breast Cancer
    1. Detects Breast Cancer 1.7 years before Breast Exam
    2. Detects lesions as small as 12 mm
    3. Benefits outweigh risks for women ages 50 to 74 years
    4. Reference
      1. Sox (1998)
  2. Test Sensitivity: 60 to 95%
    1. False Negative Rate: 15%
    2. Less effective in:
      1. Dense Breasts
      2. Women younger than age 50 years
      3. Hormone Replacement
    3. References
      1. Mushlin (1998) Am J Prev Med 14:143-53 [PubMed]
  3. Test Specificity: 94-97%
    1. False Positive Rate: 3-6%
    2. Higher rate of false positives under age 60 years
    3. 24% of U.S women have at least 1 false positive/10 yr
    4. 49% cummulative false positive risk with 10 Mammogram
    5. Reference
      1. Elmore (1998) N Engl J Med 338:1089-96
  4. Consensus Double Reading
    1. Two radiologists independently review Mammograms
    2. Identified 80 Breast Cancers per 10,000 reading
      1. Only 71 Breast Cancers found by a single reader
      2. Saved $7300 over cost of a single reader
    3. Reference
      1. Brown (1996) BMJ 312:809-12 [PubMed]
  • Risks
  1. Radiation exposure with Mammogram is NOT significant
    1. Two view Mammogram delivers less than 0.5 Centigray
    2. 200 Mammograms would be needed to raise cancer risk