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Mammography

Mammography Screening

Mammography is an x-ray examination of the breast. It is used to detect and diagnose breast disease in women who either have breast problems such as a lump, pain, or nipple discharge, as well as for women who have no breast complaints. The procedure allows detection of breast cancers, benign tumors, and cysts before they can be detected by palpation (touch).

Mammography cannot prove that an abnormal area is cancer, but if it raises a significant suspicion of cancer, tissue will be removed for a biopsy. Tissue may be removed by needle or open surgical biopsy and examined under a microscope to determine if it is cancer.

The development of digital mammography technology allows for improved breast imaging, in particular, for women less than 50 years of age, women with dense breast tissue, or women who are premenopausal or perimenopausal. Digital mammography provides electronic images of the breasts that can be enhanced by computer technology, stored on computers, and even transmitted electronically in situations where remote access to the mammogram is required. The procedure for a digital mammography is basically performed the same way as a standard mammogram.

With computer-aided detection (CAD) systems, a digitized mammographic image from a conventional film mammogram or a digitally acquired mammogram is analyzed for masses, calcifications, or areas of abnormal density that may indicate the presence of cancer. The images are highlighted by the CAD system for further analysis by the radiologist.

What is an x-ray?

X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. Standard x-rays are performed for many reasons, including diagnosing tumors or bone injuries.

X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body structures onto specially-treated plates (similar to camera film) and a "negative" type picture is made (the more solid a structure is, the whiter it appears on the film).

Anatomy of the breasts:

Each breast has 15 to 20 sections, called lobes, which are arranged like the petals of a daisy. Each lobe has many smaller lobules, which end in dozens of tiny bulbs that can produce milk.

The lobes, lobules, and bulbs are all linked by thin tubes called ducts. These ducts lead to the nipple in the center of a dark area of skin called the areola. Fat fills the spaces between lobules and ducts.

There are no muscles in the breast, but muscles lie under each breast and cover the ribs.
Each breast also contains blood vessels and vessels that carry lymph. The lymph vessels lead to small bean-shaped organs called lymph nodes, clusters of which are found under the arm, above the collarbone, and in the chest, as well as in many other parts of the body.

What are the different types of mammograms?

A screening mammogram is an x-ray of the breast used to detect breast changes in women who have no signs of breast cancer. It usually involves two x-rays of each breast. Using a mammogram, it is possible to detect a tumor that cannot be felt.

A diagnostic mammogram is an x-ray of the breast used to diagnose unusual breast changes, such as a lump, pain, nipple thickening or discharge, or a change in breast size or shape.

A diagnostic mammogram is also used to evaluate abnormalities detected on a screening mammogram. It is a basic medical tool and is appropriate in the work-up of breast changes, regardless of a woman's age.

Mammography has been used for about 30 years, and in the past 15 years technical advancements have greatly improved both the technique and results. Today, specialized equipment, used only for breast x-rays, produce studies that are high in quality but low in radiation dose.

Mammography may be used either for screening or to make a diagnosis. Women who are at high risk for breast cancer or with a history of breast cancer may be routinely screened with mammography.

Who should get a screening mammogram?

ACR and SBI recommends screening mammography should begin at age 40 for women with average-risk of breast cancer. Women at higher-risk should begin by age 30, but no sooner than 25.

Women at high risk include carriers of BRCA mutations. Women and their doctors can use assessment tools to calculate individual risk for breast cancer. The most commonly used risk assessment tool is the Gail Model which can give your individual risk of being diagnosed with breast cancer in the next 5 years.

In addition to the recommendations related to age and screening intervals, the ACR-SBI guidelines integrate use of breast MRI and ultrasound into the screening algorithm.
Women at high risk should begin annual breast MRI evaluations by age 30. Women who have at least a 20% lifetime risk of breast cancer, on the basis of family history, also should begin annual breast MRI by age 30, in addition to annual mammography.

Breast ultrasound is often used in addition to mammography for high-risk women and those with dense breast tissue that is often difficult to assess by conventional mammography.

"Evidence to support the recommendation for regular periodic screening mammography comes from the results of several randomized trials conducted in Europe and North American that included a total of nearly 500,000 women," Carol H. Lee, MD, chair of the ACR Breast Imaging Commission, said in a statement.

In a prepared statement, HHS Secretary Kathleen Sebelius pointed out that the task force does not set health policy, and she encouraged women to "keep doing what you have been doing for years -- talk to your doctor about your individual history, ask questions, and make the decision that is right for you."

Breast cancer causes about 4,500 deaths annually in women ages 40-49, and is one of the leading causes of death in women in this age group.

What conditions does a mammogram show?

A mammogram helps to identify the following conditions:

  • Calcifications—tiny mineral deposits within the breast tissue. There are two categories of calcifications:
    • Macrocalcifications—coarse calcium deposits that usually indicate degenerative changes in the breasts, such as the following:
      • aging of the breast arteries
      • old injuries
      • inflammations
    • Microcalcifications—tiny (less than 1/50 of an inch) specks of calcium. When many microcalcifications are seen in one area, they are referred to as a cluster.
  • Masses—may occur with or without associated calcifications, and may be due to different causes, including the following:
    • Cyst—a non-cancerous collection of fluid in the breast. Cysts cannot be diagnosed by physical examination alone or by mammography alone. Either breast ultrasound or aspiration with a needle is required. If a mass is not a cyst, then further imaging may be necessary.
    • Benign breast conditions—masses can be monitored with periodic mammography, but others may require immediate or delayed biopsy. About 80 percent of all breast changes that are biopsied are found to be benign (non-cancerous) when looked at under the microscope.
    • Breast cancer

How is a mammogram performed?

Usually, a mammogram is typically done on an outpatient basis. There is no specific preparation for the examination. However, a woman should not wear deodorant, powders, or lotions under the arms on the day of the examination, as these substances can interfere with the images.

If you have breast implants, be sure to tell your mammography facility that you have them when you make your appointment. You will need an x-ray technologist who is trained in working with patients with implants. This is important because breast implants can hide some breast tissue, which could make it difficult for the radiologist to see breast cancer when looking at your mammogram images.

Although each facility may have specific protocols in place, generally, a mammogram procedure follows this process:

  1. The patient should describe any symptoms or problems to the technologist prior to the examination (if any) and complete a breast history form
  2. The patient will undress from the waist up and will be given a gown to wear
  3. The patient will be positioned at the mammography unit
  4. The breast will be positioned between two plates of the mammography unit, and pressure applied to compress the tissue. (This may produce temporary discomfort.) Breast compression is necessary in order to obtain the best image with the least amount of radiation possible
  5. The patient will be asked to hold her breath for a few seconds while the x-rays are taken
  6. The technologist will step behind a protective window and the image will be taken
  7. Each breast may be x-rayed at least two times from above and from the side positions to produce the films for the physician to review
  8. After the x-rays are made, the patient will be asked to wait for a short time until the radiologist can review the films to determine if additional x-rays are necessary
  9. The screening mammography examination process takes approximately 20 to 30 minutes