The objective is to compare power Doppler sonography (PD) and dynamic contrast-enhanced MRI (MR) and PET SUV in assessing the vascularity of benign and malignant breast lesions. Sixty two patients with 89 lesions (59 malignant lesions, 30 benign lesions) were evaluated by PD, MRI (MR) and PET SUV prior to surgery. Each imaging modality was evaluated independently. Lesion vascularity on PD was graded as avascular, intermediately vascular, or hypervascular. On MR, degree of maximal enhancement (minimal, moderate, or marked) and the kinetic pattern of enhancement (persistent, plateau, washout) were graded separately. For malignant lesions, PET SUV values were correlated with MRI kinetics. Gamma variable analysis was performed to assess the degree of correlation. Of the 89 lesions 44 were invasive ductal carcinoma, 2 were intraductal cancers, 6 were invasive lobular carcinoma, and 7 were invasive cancers with mixture of ductal and lobular features. There was a high degree of correlation between degree of maximal enhancement and enhancement kinetics on MRI (G=0.074, p<0.0001). The correlation between CDS and degree of maximal gadolinium enhancement was moderate (G=0.57, p=0.02). The correlation between PD vascularity and gadolinium enhancement kinetics was weak (G=0.37, p=0.12). Invasive malignancy demonstrated moderate correlation between SUV and MRI kinetics (G=0.64, p=0.14). There is a variable degree of correlation between various imaging modalities in assessing breast lesion vascularity. Further evaluation on the relationship between subjective reader assessment and objective quantitative image analysis is required to elucidate the differences in these measures of breast tumor physiology. This work was supported in part by the NIH grant P01CA085424-03.