What is spot compression in mammography?

Spot Compression in Mammography

Spot compression is a specialized mammographic technique that uses a small compression paddle to increase detailed visualization of specific areas of concern in the breast, improving diagnostic accuracy by enhancing resolution for better characterization of abnormalities. 1

Purpose and Technique

Spot compression serves several important functions in mammographic evaluation:

• Improves visualization of suspicious areas by spreading out overlapping tissues
• Enhances resolution for better assessment of calcifications, their number, and extent
• Helps characterize equivocal findings that appear on routine mammographic views
• Can be used with any view to increase detailed visualization of specific areas 2, 1

The technique involves:

• Applying localized compression to a specific area of concern
• Using a small paddle rather than compressing the entire breast
• Can be combined with magnification for even better detail of microcalcifications

Clinical Applications

Spot compression views are particularly valuable in several clinical scenarios:

• Evaluation of mammographic abnormalities (masses, asymmetries, architectural distortion)
• Assessment of microcalcifications (especially with magnification)
• Post-surgical follow-up of the tumor excision site 2
• Characterization of equivocal findings to potentially avoid unnecessary biopsies 3

Early research demonstrated that spot compression helped characterize equivocal findings seen on routine mammographic views and improved the accuracy of mammographic interpretation. In one study, 65 of 75 lesions appeared less suspicious after spot compression, while 8 appeared more suspicious and were confirmed as cancer 3.

Integration with Other Imaging Techniques

Spot compression is typically used as part of a comprehensive diagnostic approach:

1. For women ≥40 years with breast abnormalities, diagnostic mammography with spot compression views is recommended first
2. This is followed by targeted ultrasound of the area of concern 1
3. Magnification can be combined with spot compression for optimal evaluation of microcalcifications 1

Evolving Technology

Recent developments in breast imaging technology have implications for spot compression:

• Digital breast tomosynthesis (DBT) spot compression views are now available and show improved diagnostic accuracy 4
• A 2022 study found that DBT spot compression views increased intrareader agreement, interreader agreement, and diagnostic accuracy (primarily through improved specificity) 4
• However, some research suggests that with the advent of tomosynthesis, traditional spot compression may become less necessary in certain contexts 5

Pitfalls to Avoid

When utilizing spot compression views, be aware of these potential pitfalls:

• Failure to obtain spot compression views in multiple projections may miss important features 1
• Not marking the palpable area with a radio-opaque marker can lead to missing the area of concern 1
• Inadequate positioning can result in the area of interest not being properly imaged 5
• Overlooking the need for magnification views can lead to improper evaluation of microcalcifications 1

Spot compression remains a fundamental technique in mammographic evaluation, providing crucial diagnostic information for breast abnormalities, though its role may evolve with newer technologies like digital breast tomosynthesis.