Objective Volume navigation (Vnav) combines real-time ultrasound (US) with previously acquired volume data from magnetic resonance imaging (MRI) data into a single display. The efficacy of Vnav for preoperative assessment of the extent of breast cancer lesions was evaluated in the present study.Methods Twenty-nine breast cancer patients were evaluated using Vnav during second-look US or preoperative mapping. Retrospective chart review was performed. Correlation detection rates and pathological results were evaluated.Results Vnav identified lesions that were initially detected on MRI in 23 of 29 patients (79.3%). Of the 23 patients who had US correlated lesions, pathological diagnoses of the corresponding lesions were as follows: benign (n=9) and malignant (n=14).Conclusion Vnav may be a useful technique for identification of the extent of breast cancer lesions. Objective of the Invention (Vnav) combines real-time ultrasound (US) with previously acquired volume data from magnetic resonance imaging (MRI) data into a single display. The efficacy of Vnav for preoperative assessment of the extent of breast cancer lesions was evaluated in the Present study. Methods Twenty-nine breast cancer patients were evaluated using Vnav during second-look US or preoperative mapping. Retrospective chart review was performed. Correlation detection rates and pathological results were obtained. Results Vnav identified lesions that were initially detected on MRI in 23 of the 23 patients who had US correlated lesions, pathological diagnoses of the corresponding lesions were as follows: benign (n = 9) and malignant (n = 14) .Conclusion Vnav may be a useful technique for identification of the extent of breast cancer lesions