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 50th, 75th and 90th 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 Dslow 75th 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, 75th, 90th 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.