Multimodal apparent diffusion MRI model in noninvasive evaluation of breast cancer and Ki-67 expression.

BACKGROUND

To assess the capability of multimodal apparent diffusion (MAD) weighted magnetic resonance imaging (MRI) to distinguish between malignant and benign breast lesions, and to predict Ki-67 expression level in breast cancer.

METHODS

This retrospective study was conducted with 93 patients who had postoperative pathology-confirmed breast cancer or benign breast lesions. MAD images were acquired using a 3.0 T MRI scanner with 16 b values. The MAD parameters, as flow (f, D), unimpeded (fluid) (f), hindered (f, D, and α), and restricted (f, D), were calculated. The differences of the parameters were compared by Mann-Whitney U test between the benign/malignant lesions and high/low Ki-67 expression level. The diagnostic performance was assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

The f in the malignant lesions was significantly higher than in the benign lesions (P = 0.001), whereas the f and D were found to be significantly lower (P = 0.007 and P < 0.001, respectively). Compared with individual parameter in differentiating malignant from benign breast lesions, the combination parameters of MAD (f, D, and f) provided the highest AUC (0.851). Of the 73 malignant lesions, 42 (57.5%) were assessed as Ki-67 low expression and 31 (42.5%) were Ki-67 high expression. The Ki-67 high status showed lower D, higher D and higher α (P < 0.05). The combination parameters of D, D, and α provided the highest AUC (0.691) for evaluating Ki-67 expression level.

CONCLUSIONS

MAD weighted MRI is a useful method for the breast lesions diagnostics and the preoperative prediction of Ki-67 expression level.