Correlations between apparent diffusion coefficient values of invasive ductal carcinoma and pathologic factors on diffusion‐weighted MRI at 3.0 Tesla

Purpose To investigate correlations between apparent diffusion coefficient (ADC) values of invasive ductal carcinoma (IDC) and pathologic factors on diffusion-weighted MRI. We measured the ADC values of IDC of the breast and analyzed correlations between ADC values and factors such as tumor size, axillary lymph node status, histologic grade, estrogen receptor, progesterone receptor, and human epithelial growth factor 2 (HER2) using diffusion-weighted MRI at 3.0 Tesla (T). Materials and Methods We examined 110 patients with pathologically confirmed IDC using diffusion-weighted MRI at 3.0T. The ADC values of breast cancer were calculated using two b factors (0 and 1000 s/mm2). The relationship between ADC values and tumor size, histologic grade, axillary lymph node status, hormonal receptors, and HER2 were analyzed. Results The mean ADC value of IDC (n = 110) was 0.88 ± 0.15 × 10−2 mm2/s. Tumors were subgrouped according to size (<2 cm, 2–5 cm, and ≥5 cm). Multiple comparisons within subgroups according to size showed that the ADC values for the three tumor size groups were significantly different (correlation coefficient = −0.007). The mean apparent diffusion coefficient of HER2-positive IDC was significantly higher than that of HER2-negative invasive ductal carcinoma (correlation coefficient = 0.218). Conclusion ADC values of IDC were significantly correlated with tumor size and HER2 status. J. Magn. Reson. Imaging 2015;41:175–182. © 2013 Wiley Periodicals, Inc.