Non-invasive analysis of rat ovarian angiogenesis by MRI

Magnetic resonance imaging (MRI) was employed for non-invasive analysis of vascular remodeling during follicular maturation in the PMSG/hCG rat ovary model. Changes in water diffusion and in perfusion led us to suggest that hypoxic stress may be a component in the regulation of angiogenesis in the growing follicle. However, in contrast with solid tumors of similar size, the spatial and temporal pattern of expression of vascular endothelial growth factor (VEGF), did not match the angiogenic response. The mismatch could be explained by the role of hyaluronan as a high molecular weight suppressor of angiogenesis maintaining an avascular follicular antrum.