Quantitative Assessment of Iodine Intensity of Different Types of Lesions in the Low-Energy (LE) Images of Contrast-Enhanced Spectral Mammography (CESM)

Purpose: To assess the iodine enhancement intensity of breast lesions in low energy (LE) images obtained in contrast-enhanced spectral mammography (CESM) with different tissue compositions. Materials and Methods: A 50 mm dedicated phantom with different lesion insert and iodine insert were used to assess the enhancement intensity quantitatively. The target slab of the phantom consists of three lesions + iodine inserts together and 100% adipose equivalent,100% glandular equivalent inserts alone to mimic the adipose and glandular lesion without contrast-enhancement. Each iodine inserts having a concentration of 0.5 mgI/cm3, 1.0 mgI/cm3, 2.0 mgI/cm3. The phantom was exposed under semiautomated function at 28 kV, 30 kV, and 32 kV with Mo/Rh target/filter combination. Iodine intensity was estimated for three types of lesions at three breast equivalent compositions. Results: Lesions with fatty tissue had high intensity while lesions with glandular tissues had the minimum intensity. Among fatty lesions, highest mean intensity value (0.972±0.003) observed with minimum iodine concentration (F + 0.5 mgI/cm3). The highest mean intensity value (0.882±0.001) was found related to the glandular lesion with maximum iodine concentration (G + 2.0 mgI/cm3). The one-way ANOVA statistical test confirmed that mean intensity values were significantly varied among different lesions (P < 0.05). Conclusion: LE images obtained in CESM can be used to identify the different types of lesions without performing the full field digital mammography (FFDM) as an additional examination prior to the CESM procedure.