Role of MRI in Differentiating Benign from Malignant Breast Lesions Using Dynamic Contrast Enhanced MRI and Diffusion Weighted MRI

Abstract

BACKGROUND Breast cancer is the second most common cancer in Indian women. Dynamic contrast enhanced MRI (DCE-MRI) has improved specificity in characterising breast lesions. Diffusion weighted imaging can improve the sensitivity and specificity of MRI in the evaluation of breast lesions thus differentiating between benign and malignant breast lesions. The purpose of the study was to evaluate the role of diffusion weighted MRI and dynamic contrast enhanced MRI in differentiating benign from malignant breast lesions and to compare its findings with histopathological or fine needle aspiration cytology (FNAC) findings. METHODS A descriptive diagnostic study enrolled 30 female patients of palpable breast lumps with positive findings either on mammography or ultrasound. Ultrasonography was done on HD 15 (Philips Medical Systems, USA). This was followed by MRI which was done on MULTIVA 1.5 T using a dedicated breast array coil. RESULTS Fibroadenoma accounted for majority of benign lesions (4 / 10) while invasive ductal carcinoma (IDC) accounted for majority of malignant lesions (15 / 20). 7 / 10 benign lesions showed type I curve, while majority (15 / 20) of the malignant lesions showed type III curve. 8 / 10 benign breast lesions did not show restricted diffusion on diffusion weighted imaging (DWI) while all malignant lesions showed restricted diffusion on DWI. In our study, the mean apparent diffusion coefficient (ADC) value for benign and malignant lesions was 1.59 x 10-3 mm2 / s and 0.88 x 10- 3 mm2 / s respectively. CONCLUSIONS MR morphology, DCE-MRI and DWI are useful to characterise various breast lesions. MRI features of signal intensity of hypointensity on T2WI with other associated features of irregular shape, spiculate margins, heterogeneous enhancement on DCEMRI, type III dynamic curve and reduced ADC value are strong predictors of malignancy. KEY WORDS Breast MRI, DCE-MRI, DWI, Breast Carcinoma