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.

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 3min 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 2min and 3min CE-CBBCT (2min: 48.17 vs. 0.3 HU, p<0.001; 3min: 57.38 vs. 15.43 HU, p<0.001). Enhancement differences between malignant and benign breast lesions were largest at 2min CE-CBBCT. Ductal carcinoma in situ (DCIS) showed highest mean contrast enhancement among malignant breast lesions (100.93 HU at 3min CE-CBBCT, p=0.0314) compared to invasive carcinoma of no special type with DCIS component (55.82 HU at 3min CE-CBBCT) and invasive ductal carcinoma (52.31 HU at 3min CE-CBBCT).

Conclusions: The contrast enhancement on CE-CBBCT best discriminates between malignant and benign breast lesions at 2min after CM injection. The enhancement has the potential to differentiate histopathological subtypes, with highest enhancement among malignant lesions seen for DCIS.