Diagnostic Mammography and Diagnostic Ultrasound: Comprehensive Evaluation for Breast Abnormalities
Diagnostic mammography and diagnostic ultrasound are specialized imaging techniques used to further evaluate breast abnormalities detected during screening mammography or clinical examination. 1, 2
Diagnostic Mammography
Diagnostic mammography differs from screening mammography in several key ways:
Additional specialized views: While screening mammography typically includes 2 standard x-ray images of each breast, diagnostic mammography includes additional targeted views such as spot compression, magnification views, or special mammographic views to investigate specific areas of concern 1
Purpose: Used to evaluate:
Interpretation: Results are categorized according to BI-RADS (Breast Imaging Reporting and Data System) assessment categories:
- Category 0: Incomplete assessment, needs additional imaging
- Category 1: Negative
- Category 2: Benign finding
- Category 3: Probably benign (risk of malignancy <2%)
- Category 4: Suspicious abnormality
- Category 5: Highly suggestive of malignancy (≥95% probability)
- Category 6: Known biopsy-proven malignancy 1
Diagnostic Ultrasound
Diagnostic ultrasound is frequently performed alongside diagnostic mammography, particularly for:
- Characterization of masses: Distinguishes solid masses from fluid-filled cysts
- Guidance for biopsies: Provides real-time visualization during procedures
- Evaluation in younger women: Preferred initial imaging modality for women <30 years due to increased breast density and radiation concerns 1, 2
Age-Based Approach to Initial Imaging
- Women ≥40 years: Diagnostic bilateral mammography as initial imaging, with ultrasound as needed 2
- Women 30-39 years: Either ultrasound or diagnostic mammography is appropriate 2, 3
- Women <30 years: Ultrasound is the preferred initial imaging modality 2, 4
Clinical Scenarios Requiring Diagnostic Evaluation
Recall from screening mammography:
- Additional imaging to further evaluate an abnormality detected during routine screening 1
Palpable breast mass:
Nipple discharge, skin changes, or other breast symptoms:
- Diagnostic mammogram with or without ultrasound based on age and clinical presentation 1
Management Based on Combined Imaging Assessment
The final assessment integrates findings from both diagnostic mammography and ultrasound:
- BI-RADS 1-2 (Negative/Benign): Return to routine screening 1, 2
- BI-RADS 3 (Probably Benign): Short-interval follow-up with physical exam and imaging every 6 months for 1-2 years 1, 2
- BI-RADS 4-5 (Suspicious/Highly Suggestive): Tissue sampling via core needle biopsy 1, 2
Important Considerations
- Imaging-pathology concordance: After biopsy, results must be correlated with imaging findings to ensure concordance 1, 2
- Clinical correlation: Even with negative imaging, clinically suspicious findings warrant biopsy, as imaging is not 100% sensitive 1
- Follow-up: For probably benign findings (BI-RADS 3), follow-up intervals may vary based on level of suspicion 1
Limitations and Pitfalls
- Diagnostic mammography has higher sensitivity but lower specificity compared to screening mammography 1
- Breast density can limit mammographic sensitivity, particularly in younger women 3
- Negative imaging does not completely exclude malignancy when clinical suspicion is high 2
- The term "diagnostic" can be confusing as imaging results are often not specific enough to be truly diagnostic without tissue sampling 1
Conclusion
Diagnostic mammography and ultrasound are complementary techniques that together provide high sensitivity for breast cancer detection. The appropriate selection and sequence of these imaging modalities should be based on patient age, clinical presentation, and risk factors to optimize diagnostic accuracy while minimizing unnecessary procedures.