Feasibility of Diffusion-weighted Magnetic Resonance Imaging for Differentiating Idiopathic Granulomatous Mastitis From Malignant Breast Lesions

Objective: Idiopathic granulomatous mastitis (IGM) is an inflammatory breast disease that is often challenging to differentiate from malignancy. This study investigated the role of diffusion-weighted (DW) magnetic resonance imaging in differentiating IGM from malignant breast lesions. Methods: This retrospective study included 82 female patients with IGM [with a mean age of 33.48 years, minimum (min): 22 - maximum (max): 58 years] and 85 female patients with breast cancer (with a mean age of 48.14 years, min: 31 - max: 79 years). The diagnoses of all patients were confirmed by biopsy, including 114 IGM lesions and 115 malignant lesions in the analysis. DW sequences were acquired with b-values of 0 and 1000 mm2/sec on a 1.5 T device. The apparent diffusion coefficient (ADC) values of the lesions were measured manually by placing multiple regions of interest of 50-100 mm2 in the target lesions and contralateral normal parenchyma. Results: The ADC values of both IGM (1.119±0.454x10-3 mm2/s) and malignant lesions (1066±0.610x10-3 mm2/s) were lower than those of normal parenchyma. The ADC values of the mastitis group were significantly higher than the ADC values of the carcinoma group (p=0.00). The inter-observer (r=0.627) and intra-observer (r=0.775) agreement of ADC measurements were strong. Conclusion: DW imaging is a useful noninvasive technique to differentiate between IGM and breast carcinoma.