Breast lesion morphology assessment with high and standard b values in diffusion-weighted imaging at 3 Tesla.

With increasing spatial resolution, diffusion-weighted imaging (DWI) may be suitable for morphologic lesion characterization in breast MRI – an area that has traditionally been occupied by dynamic contrast-enhanced imaging (DCE). This investigation compared DWI with b values of 800 and 1600 s/mm2 to DCE for lesion morphology assessment in high-resolution breast MRI at 3 Tesla. Multiparametric breast MRI was performed in 91 patients with 93 histopathologically proven lesions (31 benign, 62 malignant). Two radiologists independently evaluated three datasets per patient (DWI b800 ; DWI b1600 ; DCE) and assessed lesion visibility and BIRADS morphology criteria. Diagnostic accuracy was compared among readers and datasets using Cochran's Q test and pairwise post-hoc McNemar tests. Bland-Altman analyses were conducted for lesion size comparisons. Discrimination of carcinomas was superior compared to benign findings in both DWI b800 and DWI b1600 (p < 0.001) with no b value-dependent difference. Similarly, assessability of mass lesions was better than of non-mass lesions, irrespective of b value (p < 0.001). Intra-reader reliability for the analysis of morphologic BIRADS criteria among DCE and DWI datasets was at least moderate (Fleiss κ ≥0.557), while at least substantial inter-reader agreement was ascertained over all assessed categories (κ ≥0.776). In pairwise Bland-Altman analyses, the measurement bias between DCE and DWI b800 was 0.7 mm, whereas the difference between DCE and DWI b1600 was 2.8 mm. DWI b1600 allowed for higher specificity than DCE (p = 0.007/0.062). DWI can be employed for reliable morphologic lesion characterization in high-resolution breast MRI. High b values increase diagnostic specificity, while lesion size assessment is more precise with standard 800 s/mm2 images. [ABSTRACT FROM AUTHOR]