Utility of Multiparametric MRI of the Breast with Combined High b-value DWI and Dynamic Contrast MRI to Differentiate Benign and Malignant Lesions: A Cross-sectional Study

Abstract

Introduction: Breast cancer is one of the most frequent malignancies in women worldwide, and it is the leading cause of cancer mortality. Early detection is key to a better prognosis. In India, many patients are diagnosed in later stages due to the absence of screening programs and less awareness in certain regions of the country. MRI is a highly sensitive investigation that can detect small and sometimes hidden or occult lesions not visible on mammography. The diffusion-weighted sequence has the potential to be used in conjunction with mammography, thereby improving diagnostic accuracy. Aim: To evaluate the utility of multiparametric MRI (mpMRI) of the breast, combining high b-value Diffusion-Weighted Imaging (DWI) and Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI), in differentiation benign and malignant lesions. Materials and Methods: This cross-sectional study was conducted at a Dr. D.Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, India from Jan 2017 - Dec 2020. A total of 254 women with 272 breast lesions were included. All cases underwent mpMRI on a 3Tesla scanner, which included T2- weighted imaging, dynamic post-contrast study, and DWI with a b-value of 1500 sec/mm² . Sensitivity, specificity, diagnostic accuracy, and area under the curve were calculated using the results of different parameters. Comparative Receiver Operating Characteristic (ROC) curves were plotted for DCE-MRI, DWI, and mpMRI. Histopathologic diagnosis was considered the standard of reference. Results: The mean age was 43.73±13.56 years, with an age range of 18-82 years. Both benign and malignant breast lesions were most common in the 40-49 years age group, accounting for a total of 80 (31.4%) lesions. Out of the 272 lesions, 141 (52.03%) were malignant and 131 (47.97%) were benign. DCE-MRI showed 97.87% sensitivity, 80.15% specificity, and 89.33% diagnostic accuracy. Diffusion-weighted MRI showed 97.16% sensitivity, 87.02% specificity, and 92.27% diagnostic accuracy. The ROC analysis for Apparent Diffusion Coefficient (ADC) values of the 272 lesions revealed an area under the curve of 0.985 (p<0.001) and a sensitivity of 92.91%, with an ADC cut-off of 0.987x10-³ mm² /sec. The multiparametric study demonstrated 98.58% sensitivity, 93.13% specificity, and 95.95% diagnostic accuracy. The area under the curve was 0.959 for mpMRI, 0.921 for DWI, and 0.890 for DCE-MRI. Conclusion: mpMRI with DCE-MRI and DWI using a high b-value of 1500 sec/mm² can be utilised to improve diagnostic accuracy