Characterization of lesions in dense breasts: Does tomosynthesis help?

CONTEXT: Mammography in dense breasts is challenging due to lesion obscuration by tissue overlap. Does tomosynthesis offers a solution?

AIMS: To study the impact of digital breast tomosynthesis (DBT) in characterizing lesions in breasts of different mammographic densities.

SETTINGS AND

DESIGN

Prospective blinded study comparing mammography in two views with Mammography + Tomosynthesis.

METHODS AND MATERIAL: Tomosynthesis was performed in 199 patients who were assigned Breast imaging reporting and data system (BIRADS) categories 0, 3, 4, or 5 on two-dimensional (2D) mammogram. Mammograms were first categorized into one of 4 mammographic breast densities in accordance with the American College of Radiology (ACR). Three radiologists independently analyzed these images and assigned a BIRADS category first based on 2D mammogram alone, and then assigned a fresh BIRADS category after taking mammography and tomosynthesis into consideration. A composite gold-standard was used in the study (histopathology, ultrasound, follow-up mammogram, magnetic resonance imaging). Each lesion was categorized into 3 groups-superior categorization with DBT, no change in BIRADS, or inferior BIRADS category based on comparison with the gold-standard. The percentage of lesions in each group was calculated for different breast densities.

RESULTS

There were 260 lesions (ages 28-85). Overall, superior categorization was seen in 21.2% of our readings on addition of DBT to mammography. DBT was most useful in ACR Densities 3 and 4 breasts where it led to more appropriate categorization in 27 and 42% of lesions, respectively. DBT also increased diagnostic confidence in 54.5 and 63.6% of lesions in ACR Densities 3 and 4, respectively.

CONCLUSIONS

In a diagnostic setting, the utility of tomosynthesis increases with increasing breast density. This helps in identifying the sub category of patients where DBT can actually change management.