Abstract: Background and purpose: Diffusion-weighted imaging (DWI) is a non-invasive technique of breast magnetic resonance imaging (MRI). DWI is an alternative to dynamic contrast-enhanced (DCE) MRI for differentiating malignant from benign lesions in breast screening or not. This study aimed to evaluate the potential role of DWI in differentiating malignant breast lesions from benign lesions. Methods: Seventy-four patients underwent digital mammography, DCE and DWI (49 patients’ b-value of 0, 400, 600 and 800 s/mm²). The detectability, sensitivity and specificity of DWI and DCE were compared. Absolute apparent diffusion coefficient (ADC) was compared with standardized ADC for quantitative analysis. Results: Sixty-four of 74 patients had positive pathologic findings (38 malignant, 26 benign). All of the malignant lesions were detected on DWI and DCE. The sensitivity of DWI was 83.33%, 90.00% and 93.33%, and the specificity was 85.91%, 76.19% and 72.72%, for b-value of 400, 600 and 800 s/mm², respectively. The sensitivity and specificity of DCE were 86.61% and 90.48%. There was no significant difference between absolute and standardized ADC in detecting breast cancer (P>0.05). Conclusion: DWI is an important complemented technique to DCE-MRI for differentiating malignant from benign lesions in breast MRI.

Key words: Diffusion-weighted imaging, Dynamic contrast-enhanced, Magnetic resonance imaging, Breast cancer