Diagnostic Mammography

What is Diagnostic Mammography?

Diagnostic mammography is an x-ray exam of the breasts that is performed in order to evaluate a breast complaint or abnormality detected by physical exam or routine screening mammography. Diagnostic mammography is different from screening mammography in that additional views of the breast are usually taken, as opposed to two views typically taken with screening mammography. Thus, diagnostic mammography is usually more time-consuming and costly than screening mammography.

The goal of diagnostic mammography is to pinpoint the exact size and location of breast abnormality and to image the surrounding tissue and lymph nodes. In many cases, diagnostic mammography will help show that the abnormality is highly likely to be benign (non-cancerous). When this occurs, the radiologist may recommend that the woman return at a later date for a follow-up mammogram, typically in six months. However, if an abnormality seen with diagnostic mammography is suspicious, additional breast imaging (with exams such as ultrasound) or a biopsy may be ordered. Biopsy is the only definitive way to determine whether a woman has breast cancer.

What Types of Views are Taken with Diagnostic Mammography?

Typical views for diagnostic mammograms include the cranio-caudal view (CC), the medio lateral oblique view (MLO), and supplemental views tailored to the specific problem. These can include views from each side (latero medial, LM: from the side towards the center of the chest and mediolateral view, ML: from the center of the chest out), exaggerated cranial-caudal, and other special mammography views such as spot compression and magnification views. Click here to learn more about how mammography is performed.

Cranio-caudal (CC) view and mediolateral oblique (MLO) mammographic view	Latero medial (LM) mammographic view	Medio lateral (ML) mammographic view

What Types of Abnormalities Can Diagnostic Mammography Detect?

Mammography is used to detect a number of abnormalities, the two main ones being calcifications and masses. Calcifications are tiny mineral deposits within the breast tissue that appear as small white regions on the mammogram films. There are two types of calcifications: microcalcifications and macrocalcifications (see below). A mass is any group of cells clustered together more densely than the surrounding tissue. A cyst (pocket of fluid) may also appear as a mass on mammography. Radiologists may often use ultrasound to help differentiate between a solid mass and a cyst. 

Calcifications, masses and other conditions that may appear on a mammogram:

• Microcalcifications are tiny (less than 1/50 of an inch or ½ of a millimeter) specks of calcium in the breast. When many microcalcifications are seen in one area, they are referred to as a cluster and may indicate a small cancer. About half of the cancers detected by mammography appear as a cluster of microcalcifications. Microcalcifications are the most common mammographic sign of ductal carcinoma in situ (an early cancer confined to the breast ducts). Almost 90% of cases of ductal carcinoma in situ are associated with microcalcifications.

• An area of microcalcifications seen on a mammogram does not always indicate that cancer is present. The shape and arrangement of microcalcifications help the radiologist judge the likelihood of cancer. In some cases, the microcalcifications do not indicate a need for a biopsy. Instead, a physician may advise a follow-up mammogram, typically within 6 months. In other cases, the microcalcifications are more suspicious and a stereotactic biopsy is recommended. Only approximately 17% of calcifications requiring biopsy are cancerous. The radiologist may describe the shape of suspicious microcalcifications on the mammogram report as "pleomorphic" or "polymorphic."

• Macrocalcifications are coarse (large) calcium deposits that are often associated with benign fibrocystic change or with degenerative changes in the breasts, such as aging of the breast arteries, old injuries, or inflammation. Macrocalcification deposits are associated with benign (non-cancerous) conditions and do not usually require a biopsy. Macrocalcifications are found in approximately 50% of women over the age of 50.



• Masses: Another important change seen on a mammogram is the presence of a mass, which may occur with or without associated calcifications. A mass is any group of cells clustered together more densely than the surrounding tissue. A cyst (a non-cancerous collection of fluid in the breast) may appear as a mass on a mammogram film. A cyst cannot be diagnosed by physical exam alone nor can it be diagnosed by mammography alone, although certain signs can suggest the presence of a cyst or cysts. To confirm that a mass is a cyst, either breast ultrasound or aspiration with a needle is required. If a mass is not a cyst, then further imaging may be ordered. As with calcifications, a mass can be caused by benign breast conditions or by breast cancer. Some masses can be monitored with periodic mammography while others may require biopsy. The size, shape, and margins (edges) of the mass help the radiologist in evaluating the likelihood of cancer. Prior mammograms may help show that a mass is unchanged for many years, indicating a benign condition and helping to avoid unnecessary biopsy. Therefore, it is important for women to bring their previous mammogram films with them if they change mammogram facilities.
  


• Density: The glandular tissue of the breasts, or breast density, shows up as white areas on a mammogram film. In general, younger women have denser breasts than older women. Breast density can make it more difficult to detect microcalcifications and other masses with mammography, since breast abnormalities also show up as white areas on the mammogram. After menopause, the glandular tissue of the breasts is replaced with fat, typically making abnormalities easier to detect with mammography. Therefore, most physicians do not recommend that women begin receiving annual screening mammograms until they reach 40 years of age unless they are at high risk of developing breast cancer.

By law, the mammography facility is required to provide the woman with a written summary of the mammogram findings within 30 days of the mammogram. This letter is not a copy of the official radiologist’s report, but rather, it is a separate document that clearly explains whether an abnormality was detected and provides general information about that abnormality. Women who are self-referred should also receive a copy of the formal radiologist’s report. The letter will also indicate whether additional imaging or biopsy is recommended. Women should contact the mammography facility if they do not receive this letter within 30 days of their mammogram. Click here to learn more about understanding the terminology on the official mammogram report. 

What Other Exams/Procedures May be Ordered to Evaluate a Breast Abnormality?

Mammography alone cannot prove that an abnormal area is cancerous, although some abnormalities may be very characteristic of malignancy. If mammography raises a significant suspicion of cancer, additional breast imaging or biopsy may be ordered. A breast biopsy involves removing samples of tissue for examination under the microscope. This is the only way breast cancer can be definitively diagnosed. Between 65% and 80% of breast biopsies reveal benign (non-cancerous) conditions.

Other breast imaging exams that may be ordered include:

• Ultrasound (especially beneficial for distinguishing cysts from masses)
• Breast MRI (especially beneficial for imaging breast implants)
• Other exams, such as nuclear medicine imaging or T-scan 
• Ductography (also called a galactogram) is special type of contrast enhanced mammography used for imaging the breast ducts. Ductography can aid in diagnosing the cause of an abnormal nipple discharge and is valuable in diagnosing intraductal papillomas.

Additional Resources on Mammography

Imaginis provides several resources on diagnostic and screening mammography to help women understand all aspects of the exams. Follow the links below for additional information on mammography:

• General Information on Mammography
• Mammography and How it is Performed: Imaging and Positioning
• Screening Mammography
• Benefits of Receiving a Mammogram
• Key Steps for an Optimal Mammogram
• Mammogram Preparation and What to Expect During Mammography
• Find a Mammography Facility
• Mammography on Small Breasts
• Mammogram Interpretation: ACR/BI-RADS System
• Understanding the Mammogram Report
• Frequently Asked Questions About Mammography
• Mammography Quality Standards (MQSA)
• Advances in Mammography and Breast Imaging
• Digital Mammography 

Updated: May 4, 2008