The aim of the present study was to clarify the morphologic characteristics of time-intensity curves (TICs) that are useful for distinguishing benign from malignant lesions. One hundred three patients with breast lesions underwent dynamic breast MRI. The areas under the receiver operating characteristic (ROC) curves (AUC) from every component of TIC were compared between benign and malignant disease. As a result, angle of cross line between 1 and 4 min is more useful than rapid enhancement for distinguishing benign from malignant lesions.