Intravoxel incoherent motion diffusion-weighted MRI in patients with breast cancer: Correlation with tumor stroma characteristics

Purpose: To determine whether imaging parameters derived from intravoxel incoherent motion (IVIM) diffusion weighted imaging (DWI) vary according to tumor-stroma ratio(TSR) or dominant stroma type of breast cancer. Methods: We prospectively enrolled 77 patients with breast cancer who underwent IVIM DWI on a 3.0 T MR scanner. The values of IVIM parameters (D, D* and f) were measured. After surgery, TSR or dominant stroma type was evaluated. The relationship between imaging parameters and tumor stroma characteristics was analyzed. Results: The mean D and f values were lower in stroma-poor tumor than in stroma-rich tumor (P= 0.012, 0.015). The mean D value was lower in the collagen-dominant type than in fibroblast-dominant or lymphocyte-dominant type (P= 0.032, 0.043). According to multivariate linear regression analyses, tumor size (P= 0.007), TSR (P= 0.008), dominant stroma type (collagen dominant, P= 0.012), and histological grade (P= 0.031) were independently correlated with D value; and tumor size (P= 0.011), TSR (P= 0.021) and histological grade (P= 0.037) were independently correlated with f value. Conclusion: In breast cancer, D and f values show significant differences according to TSR, and D value is lower in collagen dominant type than in fibroblast dominant or lymphocyte dominant types.