Correlation of the apparent diffusion coefficient value and dynamic magnetic resonance imaging findings with prognostic factors in invasive ductal carcinoma

PURPOSE: To evaluate the correlation of the mean and minimal apparent diffusion coefficient values (ADC(mean) , ADC(minimal) ) and dynamic magnetic resonance imaging (MRI) findings with prognostic factors in invasive ductal carcinoma. MATERIALS AND METHODS: A total of 107 women with invasive ductal cancer underwent breast MRI. The ADC(mean) and ADC(minimal) of the cancers were computed. MRI findings were retrospectively evaluated according to the Breast Imaging Reporting and Data System (BI-RADS) lexicon: mass or nonmass type, mass shape, mass margin, nonmass distribution, and enhancement pattern. Histological records were reviewed for tumor size, lymph node metastasis, histologic grade, and expression of estrogen receptors (ER), progesterone receptors (PR), c-erbB-2(HER2), Ki-67, and epidermal growth factor receptors (EGFR). Correlations of ADC values and MR findings with prognostic factors were determined using the Mann-Whitney U-test and the Kruskal-Wallis test. RESULTS: The mean ADC(minimal) was 0.78 ± 0.24 (× 10⁻³ mm² /s), and the mean ADC(mean) was 1.01 ± 0.23 (× 10⁻³ mm² /s). There was a significant correlation of the ADC(mean) value with ER expression (P = 0.027) and HER2 expression (P = 0.018). There was no significant relationship between ADC(minimal) and prognostic factors or between ADC(mean) and traditional prognostic factors, PR, Ki-67 and EGFR. The majority of the mass type lesions were less than 5 cm in size and the majority of nonmass type lesions were more than 2 cm in size (P = 0.022). The margin of mass was significantly associated with lymph node metastasis (P = 0.031), ER expression (P = 0.013), PR expression (P = 0.036), HER2 expression (P = 0.019), and EGRF expression (P = 0.041). The rim internal enhancement was significantly correlated with Ki-67 expression (P = 0.008). CONCLUSION: The low ADC(mean) value was related to positive expression of ER and negative expression of HER2. A spiculated margin was related to a good prognosis, but rim enhancement was associated with a poor prognosis.