Background on: Breast Cancer, X-Ray and MRI Mammography

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Background on Breast Cancer, X-Ray and MRI
Mammography

• Ernesto Coto
• Vienna University of Technology
• Institute of Computer Graphics and Algorithms
• Computer Graphics Group

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Introduction

• First stage of a research about the State of the
  Art on Mammography for Breast Cancer Detection
• Focuses on the background knowledge about Breast
  Cancer, X-Ray and MRI Mammography

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Background Breast Cancer

• Cancer is a general term that is used to describe
  a group of more than 100 diseases that cause
  cells in the body to divide and reproduce
  abnormally without control
• These cells may join together to form a mass of
  extra tissue known as a tumor. Tumors can be
  malignant or benign
• Malignant tumors can break away from tumors and
  travel, or metastasize
• Breast cancer refers to a malignant tumor that
  has developed from breast cells

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Background Breast Cancer

• The female breast has two main components
  glandular tissue and connective tissue
• There are two general categories
• of breast cancer
• Non-invasive (or in situ)
• cancer confined to lobules or ducts
• Invasive
• cancer spread to fatty connective tissue

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Background Breast Cancer

• When breast cancer is detected before it has
  spread to lymph nodes or to other parts of the
  body, the 5-year survival rate is 97
• Early detection and early treatment can improve
  the chances of surviving breast cancer.
  Currently, mammography is the best tool available
  to detect the earliest warning signs of breast
  cancer

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Background X-Ray Mammography

• A mammogram is an x-ray examination of the
  breasts, used to detect and diagnose breast
  diseases
• Screening mammography is used as a preventive
  measure for women who have no symptoms of breast
  disease
• Diagnostic mammography involves additional x-rays
  of the breast to provide different views of the
  suspicious area, if an abnormality is detected
  during screening mammography, or in women with
  breast complaints
• The x-rays can be taken at different angles
  tailored to the specific area of abnormality. In
  addition, magnification views or spot compression
  can be used to make the area easier to evaluate

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Background X-Ray Mammography

• Mammography procedure
• Special x-ray machines developed exclusively for
  breast imaging are used to produce mammography
  films. These machines use very low doses of
  radiation and produce high-quality x-rays

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Background X-Ray Mammography

• Mammography procedure
• The patient wears an open wrap and undress above
  the waist

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Background X-Ray Mammography

• Mammography procedure
• Compressing the breast is necessary to obtain the
  best image

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Background X-Ray Mammography

• Mammography procedure
• When the breast is positioned and compression is
  complete, the technologist will leave the room or
  step behind a screen and turn on the x-ray source

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Background X-Ray Mammography

• Mammography procedure
• Magnification views or spot compression could be
  performed too

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Background X-Ray Mammography

• Results
• Calcifications are tiny calcium deposits within
  the breast tissue. Calcifications are classified
  as microcalcifications (lt 1/50 inchs) or
  macrocalcifications (larger)
• Masses
• Can be solid or liquid (Cyst)

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Background X-Ray Mammography

• Staging
• Staging is the process used to determine the
  extent a cancer has spread beyond the primary
  site
• The system used to describe staging is the
  Staging System of the American Joint Committee on
  Cancer (or TNM system), it evaluates three
  components to determine the stage of a cancer
• T The extent of the tumor, expressed in a
  numerical value from 0 to 4. Higher T numbers
  indicates a larger tumor or more extensive spread
• N the extent to which the cancer has spread to
  lymph nodes near the breast and the degree to
  which the affected nodes are fixed to other
  structures under the arm. It is expressed in a
  numerical value from 0 to 3, with the higher
  number denoting more extensive spread
• M the extent to which the cancer has
  metastasized to distant organs or to lymph nodes
  that are not next to the breast. It is shown in a
  numerical value from 0 to 1, with 1 indicating
  the most extensive spread

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Background X-Ray Mammography

• Mammography cannot determine whether an abnormal
  area is cancer, but it can provide guidance for
  further screening or diagnostic tests.
• Results of mammograms are reported using a
  standardized system called the Breast Imaging
  Reporting and Data System (BIRADS)
• Results range from Assessment incomplete to
  Highly Suggestive of Malignancy

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Background X-Ray Mammography

• Despite Mammography is acknowledged to be the
  most effective method of screening for breast
  cancer, the interpretation of screening
  mammograms is challenging
• The combination of viewing a large number of
  cases, radiologist fatigue and the complex image
  structure of the breast on a mammogram can result
  in false negative mammogram readings
• Several retrospective studies have shown that 20
  to 40 of breast cancer goes undetected at the
  screening stage
• In addition, finding cancer does not always mean
  saving lives

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Background X-Ray Mammography

• Less common diagnostic procedures
• Magnetic Resonance Imaging (MRI)
• Digital Mammography
• Positron Emission Tomography
• Ultrasound

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Background MRI Mammography

• Magnetic Resonance Imaging (MRI) can be used to
  obtain three dimensional images of the inner
  parts of the human body, without using X-rays
• MRI breast imaging is a supplemental tool, in
  addition to mammography, to help diagnose breast
  cancer
• MRI advantages over X-ray or CAT
• No radiation
• The ability to generate arbitrary
  three-dimensional views of an object of interest
• The possibility to generate images of soft body
  structures

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Background MRI Mammography

• MRI Mammography Procedure
• The main component of most MRI systems is a large
  tube-shaped or cylindrical magnet
• The patient has to wears a wrap and give away any
  metal object

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Background MRI Mammography

• MRI Mammography Procedure
• To begin the MRI exam, the patient is positioned
  on a special table inside the MRI system opening.
  A breast coil is used.

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Background MRI Mammography

• Contrast Enhanced MRI
• The method is based on the fact that a carcinoma
  is usually well vascularized due to its strong
  growth. Thus a contrast medium will quickly
  accumulate in the tumor
• The evaluation essentially consists of finding
  suspicious regions in the images, calculating the
  absorption of contrast-medium in those regions,
  and deriving the diagnosis from that data

Without contrast With contrast
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Background MRI Mammography

• Benefits of Breast MRI
• Can image breast implants and ruptures
• Highly sensitive to small abnormalities
• Used effectively in dense breasts
• Can evaluate inverted nipples for evidence of
  cancer
• Can evaluate the extent of breast cancer
• Can help determine what type of surgery is
  indicated (lumpectomy or mastectomy)
• May detect breast cancer recurrences and residual
  tumors after lumpectomy
• Can locate primary tumor in women whose cancer
  has spread to axillary (armpit) lymph nodes
• Can spot or characterize small abnormalities
  missed by mammography
• May be useful in screening women at high risk for
  breast cancer, according to recent studies

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Background MRI Mammography

• Limitations of Breast MRI
• MRI takes 30-60 minutes compared to 10-20 minutes
  for screening mammography
• The cost of MRI is several times the cost of
  mammography
• MRI requires the use of a contrast agent
• MRI patients must tolerate any claustrophobia
• MRI can be non-specific often cannot distinguish
  between cancerous and non-cancerous tumors
• Minimally invasive breast biopsy techniques need
  to be further developed to evaluate abnormalities
  detected with MRI
• Advanced MRI techniques are often not available
  at most centers (currently available at research
  centers)

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Further work

• CAD Systems and Techniques for Mammography
• Registration
• Segmentation
• Visualization