Diffusion magnetic resonance imaging in breast cancer characterisation: correlations between the apparent diffusion coefficient and major prognostic factors.

PURPOSE: This study was done to investigate the correlation between the apparent diffusion coefficient (ADC) and prognostic factors of breast cancer. MATERIALS AND METHODS:From January 2008 to June 2011, all consecutive patients with breast cancer who underwent breast magnetic resonance imaging (MRI) and subsequent surgery in our hospital were enrolled in our study. The MRI protocol included a diffusion-weighted imaging sequence with b values of 0 and 1,000 s/mm2. For each target lesion in the breast, the ADC value was compared with regard to major prognostic factors: histology, tumour grade, tumour size, lymph node status, and age. RESULTS: A total of 289 patients with a mean age of 53.49 years were included in the study. The mean ADC value of malignant lesions was 1.02 × 10-3 mm2/s. In situ carcinomas, grade 1 lesions, and tumours without lymph nodal involvement had mean ADC values that were significantly higher than those of invasive carcinomas (p = 0.009), grade 2/3 lesions (p < 0.001), and tumours with nodal metastases (p = 0.001). No significant differences were observed in ADC values among tumours of different sizes or among patient age groups. CONCLUSIONS: ADC values appear to correlate with tumour grade and some major prognostic factors.