Is contrast enhancement required to visualize a known breast tumor in a pre-operative CT scan?

Background and purpose: A pre-operative CT scan with contrast enhancement (CE) has recently been proposed to improve tumorbed delineation in breast conserving therapy. However, it is not clear whether CE is required for visualization of a known breast tumor. The main aims of this study were to compare the sensitivity of a CE-CT scan with a native CT scan (i.e. without CE) and to identify characteristics predictive for the requirement of CE. Patients and methods: Both a CE-CT and a native CT were made in 58 breast cancer patients (age 37-75 yr), prior to breast conserving surgery. Visibility of the tumor on CT was scored by three observers (clearly visible/doubtful/not visible). Age, tumor size, palpable tumor yes/no, histology, and visibility on mammography were analyzed with respect to the visibility of the tumor on the native CT. Results: The sensitivity for tumor detection was better for CE-CT (95%) than for native CT (83%) (p <0.001). Only mammographic visibility scores appeared to be significantly correlated with the visibility of the tumor on the native CT (p = 0.013). Conclusion: In most patients CE is not required to visualize a known breast tumor. Mammographic visibility is a good parameter to decide on the use of CE.