Discrimination of Breast Cancer from Healthy Breast Tissue Using a Three-component Diffusion-weighted MRI Model.

Abstract

Diffusion-weighted MRI (DW-MRI) is a contrast-free modality that has demonstrated ability to discriminate between predefined benign and malignant breast lesions. However, how well DW-MRI discriminates cancer from all other breast tissue voxels in a clinical setting is unknown. Here we explore the voxelwise ability to distinguish cancer from healthy breast tissue using signal contributions from the newly developed three-component multi-b-value DW-MRI model. Patients with pathology-proven breast cancer from two datasets (<i>n</i> = 81 and <i>n</i> = 25) underwent multi-b-value DW-MRI. The three-component signal contributions <i>C</i> ₁ and <i>C</i> ₂ and their product, <i>C</i> ₁ <i>C</i> ₂, and signal fractions <i>F</i> ₁, <i>F</i> ₂, and <i>F</i> ₁ <i>F</i> ₂ were compared with the image defined on maximum b-value (<i>DWI</i> _max), conventional apparent diffusion coefficient (<i>ADC</i>), and apparent diffusion kurtosis (<i>K</i> _app). The ability to discriminate between cancer and healthy breast tissue was assessed by the false-positive rate given a sensitivity of 80% (FPR₈₀) and ROC AUC. Mean FPR₈₀ for both datasets was 0.016 [95% confidence interval (CI), 0.008-0.024] for <i>C</i> ₁ <i>C</i> ₂, 0.136 (95% CI, 0.092-0.180) for <i>C</i> ₁, 0.068 (95% CI, 0.049-0.087) for <i>C</i> ₂, 0.462 (95% CI, 0.425-0.499) for <i>F</i> ₁ <i>F</i> ₂, 0.832 (95% CI, 0.797-0.868) for <i>F</i> ₁, 0.176 (95% CI, 0.150-0.203) for <i>F</i> ₂, 0.159 (95% CI, 0.114-0.204) for <i>DWI</i> _max, 0.731 (95% CI, 0.692-0.770) for <i>ADC</i>, and 0.684 (95% CI, 0.660-0.709) for <i>K</i> _app. Mean ROC AUC for <i>C</i> ₁ <i>C</i> ₂ was 0.984 (95% CI, 0.977-0.991). The <i>C</i> ₁ <i>C</i> ₂ parameter of the three-component model yields a clinically useful discrimination between cancer and healthy breast tissue, superior to other DW-MRI methods and obliviating predefining lesions. This novel DW-MRI method may serve as noncontrast alternative to standard-of-care dynamic contrast-enhanced MRI.