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 (Dslow ), pseudodiffusivity (Dfast ), and perfusion fraction (Dpf ) 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 Dslow 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 Dpf 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 Dslow metrics differentiated between ER-positive and -negative groups, and the Dpf metrics were associated with the size of the DCIS component.

LEVEL OF EVIDENCE: 4 J. MAGN. RESON. IMAGING 2017;45:1394-1406.