Diffusion-Weighted MRI for Diagnosis of Multifocal, Multicentric Breast Cancer

Detection of multifocal, multicentric breast cancer in patients with breast cancer affects surgical decision. Histology-proven additional cancer foci have been reported to be detected in 21.0% to 63.0% of affected breasts in women thought to have localized cancer based on clinical assessment and mammography. Dynamic contrast-enhanced (DCE) MRI is often applied in the preoperative local staging of breast cancer due to its high sensitivity and identifies additional foci that would have otherwise remained undetected on clinical assessment and conventional imaging (mammography and ultrasonography). However, DCE MRI is limited in use due to its low specificity with high false positive rate, causing unnecessary and incorrect conversion to more extensive surgery. Diffusion-weighted MRI (DWI) is a fast, functional MRI technique that measures the movement of water molecules to create tissue contrast without the need for contrast injection. Breast malignancies exhibit hindered diffusion and appear hyperintense on DWI with low apparent diffusion coefficient (ADC) values compared to normal surrounding tissue or benign tumors. Multiple studies including one prospective multi-center trial showed that DWI can reduce unnecessary benign biopsies of suspicious mammographic or DCE MRI-detected lesions and DWI is now considered as an important part of multi-parametric breast MRI protocols. However, little is known about the role of DWI as an adjunct to DCE MRI in the local staging of women with breast cancer. The purpose of our study is to determine whether DWI improves the performance of preoperative DCE MRI in the evaluation of additional lesions in breast cancer patients.