Virtually all solid tumors need new blood vessels to grow after obtaining a size of a few mm3.Unlike normal vessels,tumor vessels are characteristically leaky,fragile,and incompletely formed.T1-weighted dynamic contrast enhanced (DCE) MRI is sensitive to detect this loss of vascular integrity.Moreover,there have increased vessel density and mean capillary diameter in malignant lesions compared with those in benign lesions.T2*-weighted dynamic susceptibility contrast (DSC) MRII has been used to detect this increased vascularity.