Peritumoral apparent diffusion coefficients for prediction of lymphovascular invasion in clinically node-negative invasive breast cancer

ObjectivesTo evaluate whether visual assessment of T2-weighted imaging (T2WI) or an apparent diffusion coefficient (ADC) could predict lymphovascular invasion (LVI) status in cases with clinically node-negative invasive breast cancer. Materials and methodsOne hundred and thirty-six patients with 136 lesions underwent MRI. Visual assessment of T2WI, tumour-ADC, peritumoral maximum-ADC and the peritumour-tumour ADC ratio (the ratio between them) were compared with LVI status of surgical specimens. ResultsNo significant relationship was found between LVI and T2WI. Tumour-ADC was significantly lower in the LVI-positive (n = 77, 896 +/- 148 x 10(-6) mm(2)/s) than the LVI-negative group (n = 59, 1002 +/- 163 x 10(-6) mm(2)/s; p < 0.0001). Peritumoral maximum-ADC was significantly higher in the LVI-positive (1805 +/- 355 x 10(-6) mm(2)/s) than the LVI-negative group (1625 +/- 346 x 10(-6) mm(2)/s; p = 0.0003). Peritumour-tumour ADC ratio was significantly higher in the LVI-positive (2.05 +/- 0.46) than the LVI-negative group (1.65 +/- 0.40; p < 0.0001). Receiver operating characteristic curve analysis revealed that the area under the curve (AUC) of the peritumour-tumour ADC ratio was the highest (0.81). The most effective threshold for the peritumour-tumour ADC ratio was 1.84, and the sensitivity, specificity, positive predictive value and negative predictive value were 77 % (59/77), 76 % (45/59), 81 % (59/73) and 71 % (45/63), respectively. ConclusionsWe suggest that the peritumour-tumour ADC ratio can assist in predicting LVI status on preoperative imaging.