Objective:To test the use of diffusion-weighted imaging (DWI) in stratifying suspicious
breast lesions (BI-RADS 4), correlating them with histopathology. We also
investigated the performance of DWI related to the main enhancement patterns
(mass and non-mass) and tested its reproducibility.Materials and Methods:Seventy-six patients presented 92 lesions during the sampling period. Two
independent examiners reviewed magnetic resonance imaging studies, described
the lesions, and determined the apparent diffusion coefficient (ADC) values.
Differences among benign, indeterminate- to high-risk, and malignant
findings, in terms of the ADCs, were assessed by analysis of variance. Using
receiver operating characteristic (ROC) curves, we compared the performance
of ADC values in masses and non-mass lesions, and tested the reproducibility
of measurements by determining the coefficient of variation and smallest
real difference.Results:Among the 92 lesions evaluated, the histopathology showed that 37 were
benign, 11 were indeterminate- to high-risk, and 44 were malignant. The mean
ADC differed significantly among those histopathological groups, the value
obtained for the malignant lesions (1.10 × 10-3
mm2/s) being significantly lower than that obtained for the
other groups (p < 0.001). ROC curves demonstrated that DWI performed
better when applied to masses than when applied to non-mass lesions (area
under the curve, 0.88 vs. 0.67). Reproducibility was good (coefficient of
variation, 7.03%; and smallest real difference, ± 0.242 ×
10-3 mm2/s).Conclusion:DWI can differentiate between malignant and nonmalignant (benign or
indeterminate- to high-risk) lesions, showing better performance for masses.
Nevertheless, stratification based on histopathological criteria that are
more refined has yet to be achieved.