Pathophysiologic basis of contrast enhancement in breast tumors

While the diagnostic benefits of gadolinium (Gd)-chelate contrast agents ar e firmly established in magnetic resonance imaging (MRI) of tumors, the pat hophysiologic basis of the enhancement observed and its histopathologic cor relate remained vague. Tumor angiogenesis is fundamental for growth and met astasis and also of interest in new therapeutic concepts. By correlative an alysis of a) histology; b) vascular density (CD31): and c) vascular permeab ility (vascular permeability factor/vascular endothelial growth factor [VPF /VEGF]), we found a) significantly (P < 0.001) faster exchange rates in mal ignant compared with benign breast lesions; b) distinct differences in enha ncement characteristics between the histologic types (invasive ductal carci noma, invasive lobular carcinoma, and ductal carcinoma in situ); and c) dep endence of enhancement kinetics on the VPF/VEGF expression. The pathophysio logic basis for the differences In contrast enhancement patterns of tumors detectable by MRI is mainly due to vascular permeability, which leads to mo re characteristic differences than vascular density. MRI is able to subclas sify malignant breast tumors due to their different angiogenetic properties , (C) 1999 Wiley-Liss, Inc.