Contrast-enhanced cone-beam breast-CT: Analysis of optimal acquisition time for discrimination of breast lesion malignancy

Objective: To investigate the optimal acquisition time of contrast-enhanced cone-beam breast-CT (CBBCT) for best discrimination of breast lesion malignancy and whether contrast enhancement can aid in classification of tumor histology. Material and methods: The study included patients with BI-RADS 4 or 5 lesions identified on mammography and/or ultrasound. All patients were examined by non-contrast (NC-CBBCT) and contrast-enhanced CBBCT (CE-CBBCT) at 2 and 3 min after contrast media (CM) injection. Lesion enhancement of suspicious breast lesions was evaluated in corresponding CBBCT slices. Results: A total of 31 patients with 57 breast lesions, 30 malignant and 27 benign, were included. Malignant breast lesions demonstrated higher contrast enhancement than benign breast lesions at both 2 min and 3 min CE-CBBCT (2 min: 48.17 vs. 0.3 HU, p < 0.001; 3 min: 57.38 vs. 15.43 HU, p < 0.001). Enhancement differences between malignant and benign breast lesions were largest at 2 min CE-CBBCT. Ductal carcinoma in situ (DCIS) showed highest mean contrast enhancement among malignant breast lesions (100.93 HU at 3 min CE-CBBCT, p = 0.0314) compared to invasive carcinoma of no special type with DCIS component (55.82 HU at 3 min CE-CBBCT) and invasive ductal carcinoma (52.31 HU at 3 min CE-CBBCT). Conclusions: The contrast enhancement on CE-CBBCT best discriminates between malignant and benign breast lesions at 2 min after CM injection. The enhancement has the potential to differentiate histopathological subtypes, with highest enhancement among malignant lesions seen for DCIS.