Intravoxel incoherent motion (IVIM)‐derived parameters in diffusion‐weighted MRI: Associations with prognostic factors in invasive ductal carcinoma

Purpose To investigate relationships between intravoxel incoherent motion (IVIM) metrics of invasive ductal carcinoma of the breast and prognostic factors. Materials and Methods This retrospective study included a total of 82 masses from 72 patients who underwent 3T breast magnetic resonance imaging (MRI) and diffusion‐weighted imaging. IVIM metrics of tissue diffusivity (D slow ), pseudodiffusivity (D fast ), and perfusion fraction (D pf ) were measured using histogram analysis for whole lesion volumes. We evaluated relationships between IVIM metrics and prognostic factors or subtypes of invasive ductal carcinoma. Results The D slow 50 th , 75 th , and 90 th percentile metrics were reduced in the estrogen receptor (ER)‐positive group compared with the ER‐negative group (individually, P = 0.044, 0.024, 0.045). Additionally, the D slow 75 th percentile value was a significant differentiator of histologic grade, tumor subtype, and Ki‐67 grouping (individually, P = 0.024, 0.049, 0.016). The D pf mean, 75 th , 90 th percentile, skewness, and kurtosis metrics were correlated with the size of ductal carcinoma in situ (DCIS) component (individually, P = 0.034, 0.032, 0.027, 0.013, 0.013). Conclusion The D slow metrics differentiated between ER‐positive and ‐negative groups, and the D pf metrics were associated with the size of the DCIS component. Level of Evidence : 4 J. MAGN. RESON. IMAGING 2017;45:1394–1406