Figure 5b. (a) Graph illustrates results of receiver operating characteristic analysis of the postcontrast peripheral vessel numbers in 86 breast masses, for classification of benign and malignant disease. The area under the curve is 0.77, and the optimal cutoff value is four postcontrast peripheral vessels. (b) Graph illustrates results of receiver operating characteristic analysis of the combined score for increase in peripheral vessel number and duration of enhancement in 32 axillary lymph nodes, for classification of benign and malignant disease. The area under the curve is 0.86, and the optimal score is 0.41.