Dynamic contrast-enhanced and diffusion-weighted MRI of estrogen receptor-positive invasive breast cancers: Associations between quantitative MR parameters and Ki-67 proliferation status.

PURPOSE: To explore the association between quantitative parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) and Ki-67 proliferation status in patients with estrogen receptor (ER)-positive invasive breast cancer.

MATERIALS AND METHODS: We retrospectively reviewed the records of 88 patients with ER-positive invasive breast cancer who underwent preoperative DCE-MRI and DWI on a 3T scanner. Perfusion parameters (Ktrans , Kep , and Ve ) and apparent diffusion coefficients (ADCs) were recorded, and we correlated these data with the Ki-67 status. The Ki-67 proliferation index was categorized as high (≥14%) or low (<14%).

RESULTS: In the high-Ki-67 group, the mean Ktrans was significantly higher (P < 0.001) than that of the low-Ki-67 group, and the mean ADC significantly lower (P < 0.001). However, the mean Kep and Ve values did not differ between the two groups (P = 0.248 and P = 0.055, respectively). Univariate analysis showed that a higher Ktrans (>0.274), a lower ADC (≤0.893 × 10-3 mm2 /s), a larger tumor size (>2 cm), a higher histological grade (grade 3), the presence of axillary metastasis, and positive P53 status were significantly associated with high-Ki-67 status (all P values < 0.05). Of these variables, a higher Ktrans (>0.274; adjusted odds ratio [OR] = 9.027, 95% confidence interval [CI] = 1.929-42.245; P = 0.005) and a higher histological grade (grade 3; adjusted OR = 7.510, 95% CI = 1.305-43.205; P = 0.024) independently predicted a high Ki-67 status.

CONCLUSION: Ktrans derived from DCE-MRI is associated independently with the Ki-67 proliferation status in patients with ER-positive invasive breast cancer.

LEVEL OF EVIDENCE: 4 J. Magn. Reson. Imaging 2017;45:94-102.