A mammogram is a specialized medical imaging procedure that uses low-dose X-rays to create detailed pictures of the breast tissue. This technology is a fundamental part of a comprehensive breast health strategy, allowing healthcare providers to detect changes that may be too small to feel during a physical examination. The term “bilateral” indicates that the procedure involves the imaging of both the left and right breasts. A bilateral mammogram, whether performed for routine screening or diagnostic purposes, provides a comparative view of both breasts, which is helpful for identifying subtle abnormalities.
Defining the Bilateral Mammogram
The term bilateral mammogram describes an examination where a technologist captures images of both breasts using X-ray technology. This procedure falls into two main categories: screening and diagnostic. A screening mammogram is a routine check performed annually on patients who have no current symptoms, typically involving two standard views of each breast.
A diagnostic bilateral mammogram is a more focused examination ordered when a specific concern exists. While it uses the same low-dose X-ray equipment, the diagnostic procedure often involves the technologist taking more images, including specialized views like magnification or spot compression. These additional images provide the radiologist with a clearer, more detailed look at a specific area of interest. The goal is to obtain a more definitive assessment than standard screening.
Key Indications: Why Your Doctor Ordered It
A diagnostic bilateral mammogram is ordered to investigate a specific finding or symptom requiring detailed evaluation. One common reason is the follow-up of an abnormal result from a recent screening mammogram, where the initial images showed a suspicious area, such as microcalcifications or a mass. The additional views taken during the diagnostic exam help the radiologist determine if the finding is indeed a concern or simply an overlap of normal breast tissue.
It is also the recommended first step when a patient or physician identifies a new symptom in either breast. Such symptoms can include a newly palpable lump or area of thickening, spontaneous nipple discharge, or noticeable skin changes like dimpling or retraction. The detailed images from the diagnostic procedure help characterize the nature of the symptom and its underlying cause.
Targeted Surveillance and Dense Tissue
The test is also used for patients with a personal history of breast cancer who require more frequent or targeted surveillance than standard screening provides. This detailed imaging allows for close monitoring of the remaining breast tissue for recurring changes. Furthermore, a diagnostic mammogram may be ordered for patients with dense breast tissue. Dense tissue contains more glandular and fibrous components, which appear white on a mammogram, potentially obscuring small masses.
Preparing for and Undergoing the Procedure
Preparation for a bilateral mammogram focuses on ensuring the clearest possible images are obtained. Patients are generally advised to avoid applying deodorants, antiperspirants, powders, lotions, or perfumes to the chest or underarm area on the day of the exam. The metallic particles found in some of these products can appear as white spots on the X-ray, creating artifacts that may obscure real tissue findings or be mistaken for calcifications.
It is helpful to wear a two-piece outfit, as you will be asked to undress from the waist up and wear a gown provided by the facility. If you have had previous mammograms performed at a different location, bringing those images or reports is helpful for the radiologist to compare with the new study. Scheduling the appointment for a time when the breasts are less sensitive, such as the week following a menstrual period, can also minimize potential discomfort.
During the procedure, a certified technologist positions one breast at a time between two plates on the mammography machine. The machine applies firm compression for a brief period, typically 10 to 15 seconds per image. Compression is necessary to spread the breast tissue evenly, reduce motion blur, minimize the radiation dose, and create a high-quality, readable image. A diagnostic exam often takes longer than a screening because the technologist takes multiple specialized views, and the radiologist may review the images in real-time to request further views.
Interpreting the Results and Follow-Up Care
The results of the bilateral mammogram are communicated using the Breast Imaging Reporting and Data System, commonly referred to as BI-RADS. This standardized system helps radiologists categorize findings on a scale from 0 to 6, providing a consistent framework for communicating results and determining the next steps.
A BI-RADS Category 0 means the assessment is incomplete and requires additional imaging or comparison with previous exams before a final category can be assigned. Other categories include:
- Category 1 indicates a negative finding with no abnormalities, suggesting a return to routine annual screening.
- Category 3 is considered probably benign, meaning it has a very low chance of being malignant, and typically requires a short-term follow-up mammogram in six months to monitor its stability.
- Categories 4 or 5 are considered suspicious or highly suggestive of malignancy, respectively, and usually lead to a recommendation for a tissue sampling procedure, such as a biopsy.
Regardless of the category, the radiologist sends a detailed report to the referring physician, who will then discuss the findings and the recommended follow-up plan with the patient.