A diagnostic mammogram is a targeted X-ray examination of the breast tissue used to investigate a specific finding or symptom. This specialized imaging test is performed when an area of concern requires a more detailed look than a standard screening provides. The diagnostic exam serves as a focused tool to clarify whether a suspicious area is benign or requires further medical attention.
Screening Versus Diagnostic Mammography
The fundamental distinction between the two types of mammography lies in their purpose and the patient’s status. A screening mammogram is a routine preventive measure performed annually on women who show no signs or symptoms of breast disease. This exam typically captures two standard images of each breast to look for subtle signs of cancer before a mass can be felt or other symptoms appear.
A diagnostic mammogram is not a routine check but a targeted investigation. It is ordered when a woman presents with a specific symptom, such as a palpable lump, nipple discharge, pain, or changes in the skin texture of the breast. This exam is also performed as a follow-up when a prior screening mammogram has revealed an area that looks suspicious, such as microcalcifications or a mass.
Specialized Imaging Techniques
The procedural difference during a diagnostic mammogram is the use of specialized, problem-solving views to zero in on the area of concern. Unlike a screening exam, the radiologist is often involved in real-time, guiding the technologist to capture the most informative images. This immediate oversight ensures that the specific finding is thoroughly evaluated.
One of the specialized methods is the use of spot compression views, which employ a smaller compression paddle than the standard one. This smaller paddle applies focused pressure to a very localized area, which helps to spread out overlapping breast tissue. Spreading the tissue allows the radiologist to better determine if a suspected mass is a true finding or simply a collection of normal tissue appearing dense due to overlap.
Another technique is the magnification view, which is frequently used to examine small findings, particularly clusters of tiny calcium deposits known as microcalcifications. This view increases the spatial resolution and provides an enlarged image, allowing for a clearer assessment of the shape, margins, and distribution of these deposits. The ability to scrutinize these fine details helps the radiologist categorize the finding as benign, suspicious, or highly suggestive of malignancy.
Interpreting the Findings and Follow-up
The results of a diagnostic mammogram are communicated using a standardized language known as the Breast Imaging Reporting and Data System, or BI-RADS. This system assigns a category, numbered from 0 to 6, to classify the findings and recommend the appropriate next steps. This standardized scoring helps ensure consistent communication between all healthcare providers involved in the patient’s care.
A score of Category 0 indicates an incomplete assessment, meaning the radiologist requires further imaging, such as an ultrasound or comparison with prior mammograms, before a final category can be assigned. Category 3 is assigned to a finding considered probably benign, with a very low chance of being cancerous (less than 2%). For this category, the standard follow-up is a short-interval re-evaluation, typically in six months, to confirm the stability of the finding.
When a finding appears suspicious, it is assigned Category 4 or 5. Category 4 covers abnormalities for which malignancy cannot be excluded, while Category 5 is highly suggestive of malignancy (at least 95% probability). Both Category 4 and 5 findings generally lead to a recommendation for a tissue sampling procedure, or biopsy, to obtain a definitive diagnosis.