Diagnostic mammograms are prescribed in cases where there are suspicious changes such as lump or pain in the breast or nipple discharge. If there have been any abnormal findings on a screening mammogram, a diagnostic mammogram is required. Though technically a diagnostic mammogram is similar to a screening mammogram, a diagnostic mammogram focuses on the particular symptoms or problems such as breast lumps or mass. A diagnostic mammogram provides additional views and makes use of special techniques to magnify the abnormal area of the breast.
Mammography involves use of solid-state detectors that aid in detecting early breast cancer in women. These detectors work much like those that are found in digital cameras. The images produced can be stored on a computer. It is essential that women going in for a mammogram do not wear lotions or deodorants on their breasts or underarms. The breast is placed on a special platform and compressed with a paddle so that the tissue is spread out. This aids in examining every bit of breast tissue sans overlapping. There might be slight discomfort when the breast is pressed by the mammogram compression device. Screening mammograms aids in detecting small abnormal tissue growths. A screening mammogram helps in identifying cysts, calcifications and tumors within the breast. Interpretation of the mammogram results can be difficult as there can be inaccurate readings due to breast implants, powder or salve on the breasts. If there are any regions that need special mammogram views, an x-ray marker is taped on the area. In some cases, a diagnostic mammogram is prescribed.
Breast density compares the amount of fat in the breast to the amount of tissue present. It is a measure used to describe mammogram images and is not a measure of how the breast feels (breast size and firmness). Breast tissue is made up of milk gland, milk ducts and supportive tissues (dense breast tissue) and fatty tissue (non- dense breast tissue).
Higher breast density indicates that the breast and connective tissue are denser when compared to the fat present in the breast. Lower breast density indicates more fat when compared to breast and connective tissue.
BIRADS or BI-RADS means Breast Imaging Reporting and Data System - a standard established by the American College of Radiology. This helps place findings from mammogram screenings into well-defined categories:
BI-RADS type 1: fatty; breast is almost entirely fat. Glandular tissue is less than 25%.
BI-RADS type 2: scattered fibroglandular; breast has scattered areas of fibroglandular density.
BI-RADS type 3: heterogeneously dense; breast tissue is heterogeneously dense.
BI-RADS type 4: dense; breast tissue is extremely dense. The breast contains greater than 75% glandular and fibrous tissue.
Dense breasts may be common and may not always pose a health issue. However women with high breast density are more prone to breast cancer when compared to women with low breast density. It is unclear as to why dense breasts may be more cancer prone. In a few cases women with low breast density are prone to develop breast cancer due to aging or menopause. 2/3 of pre-menopausal and 1/4 of post menopausal women (40%) have dense breast tissue.
A mammogram helps in identifying the density of breast. Women with dense breasts have more dense tissue than fatty tissue. Dense breasts look white or grey. Thus for women with dense breasts it may be difficult to identify cancer using a mammogram as both the dense breast tissue and cancer look grey or white in color in the image. Whereas for women with more fatty breasts it is easy to identify cancer as fatty tissues look black cancer look grey or white in color.
The 'success' rate of Mammogram detecting incidence of cancer depends on several factors:
In younger women with denser breasts, mammography is less sensitive than in older women with fatty breasts where mammography can detect at least 90% of malignancies. Smaller tumors especially those without calcifications are more difficult to detect especially in dense breasts. Diagnostic mammography is associated with higher sensitivity but lower specificity as compared to screening mammography.
Factors that affect breast density
Factors increasing breast density
- High breast density is common among younger women and varies based on the age and weight of the woman.
- Pre-menopausal women tend to have dense breasts.
- Healthy women are more likely to have dense breast when compared to obese women.
- Medication like menopausal hormone therapy or other medications that contain hormones may affect the breast density of a woman. These medications tend to increase the breast density of the woman.
Factors lowering breast density
- Breast density of a woman lowers as she gets older.
- Weight gain
- Vitamin D and calcium intake in pre-menopausal women
Women with high breast density
- Discuss after mammogram with their health care provider. In case the woman belongs to a high risk group classified based on gene mutation study or family history, then she should get an MRI done.
- Adapt a healthy lifestyle.
- Quit smoking
- Exercise regularly
- Limit alcohol consumption
- Eat a nutritious diet.
- Should undergo Breast Self Examination regularly.
- Get a doctor to examine the breasts every year.
- A digital mammogram every year from the age of 40.
- MRI and other imaging studies as per doctor recommendation