Correlation between perfusion-weighted magnetic resonance imaging parameters and vascular endothelial growth factors, microvascular density, hypoxia-inducible factor 1α

Objective To investigate the relationship between perfusion-weighted magnetic resonance imaging (PWI) parameters and vascular endothelial growth factor (VEGF), microvascular density (MVD) and hypoxia-inducible factor 1α (HIF-1α) in nasopharyngeal carcinoma (NPC). Methods 94 NPC patients were prospectively studied, and the region of interest was noted by fiberscope. Before the treatment , the common magnetic resonance and PWI were used to obtain the images of region of interest and the relative parameters including transfer constant (Ktrans), rate constant of back flux (Kep), extravascular extracellular volume fraction(Ve), fractional plasm volume (fPV) were calculated, then the marking tissues were detected by biopsy. Immunohistochemical staining was conducted to detect the expressions of VEGF, MVD and HIF-1α, and the relationships between the parameters and proteins were analyzed. Results The positive rates of VEGF and HIF-1α in the NPC tissues were 71.27 % (67/94) and 30.85 % (29/94). There was a significant positive correlation between VEGF and MVD [VEGF-positve vs. VEGF-negtive: (31.273 ± 14.81)/mm2 vs. (23.633 ± 16.56)/mm2, r= 0.322, P= 0.037], but the expression of HIF-1α was not significantly correlated with the VEGF and MVD. The significantly positive correlation was found between VEGF and fPV (r= 0.339, P= 0.041), besides, there were no relations among the rest parameters. Conclusion PWI parameter fPV is positively related with VEGF, indicating that PWI could show angiogensis of NPC to some degree, and provide a guidance for predicting the radiosensitivity of NPC. Key words: Nasopharyngeal neoplasms; Magnetic resonance imaging; Perfusion imaging; Vascular endothelial growth factors; Hypoxia-inducible factor 1, alpha subunit; Microvascular density