Perfusion Parameters of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Patients with Rectal Cancer: Correlation with Microvascular Density and Vascular Endothelial Growth Factor Expression

OBJECTIVE: To determine whether quantitative perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) correlate with immunohistochemical markers of angiogenesis in rectal cancer. MATERIALS AND METHODS: Preoperative DCE-MRI was performed in 63 patients with rectal adenocarcinoma. Transendothelial volume transfer (Ktrans) and fractional volume of the extravascular-extracellular space (Ve) were measured by Interactive Data Language software in rectal cancer. After surgery, microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression scores were determined using immunohistochemical staining of rectal cancer specimens. Perfusion parameters (Ktrans, Ve) of DCE-MRI in rectal cancer were found to be correlated with MVD and VEGF expression scores by Spearman's rank coefficient analysis. T stage and N stage (negative or positive) were correlated with perfusion parameters and MVD. RESULTS: Significant correlation was not found between any DCE-MRI perfusion parameters and MVD (rs = -0.056 and p = 0.662 for Ktrans; rs = -0.103 and p = 0.416 for Ve), or between any DCE-MRI perfusion parameters and the VEGF expression score (rs = -0.042, p = 0.741 for Ktrans ; r = 0.086, p = 0.497 for Ve) in rectal cancer. TN stage showed no significant correlation with perfusion parameters or MVD (p > 0.05 for all). CONCLUSION: DCE-MRI perfusion parameters, Ktrans and Ve, correlated poorly with MVD and VEGF expression scores in rectal cancer, suggesting that these parameters do not simply denote static histological vascular properties.

Contribuição ao estudo da influência da radiação ionizante pré-operatória sobre a marcação do linfonodo sentinela do reto com azul patente: estudo experimental em ratos / Contribution to the study of the influence of preoperative ionizing radiation on the identification of the sentinel lymph node with patent blue: an experimental in rats

A radiação ionizante prévia promove alterações actínicas em tecidos peritumorais,o que poderia influenciar a demarcação do linfonodo sentinela.O presente estudo desenvolveu modelo experimental para demarcação do linfonodo sentinela do reto do rato e para definição da dose de radiação (curva de calibração).O objetivo foi avaliar a influência da radiação ionizante pré-operatória sobre a marcação, com corante azul patente, do linfonodo sentinela do reto de ratos.A amostra foi constituída por 40 ratos machos Wistar e dividida em 2 grupos:Grupo 1(controle não irradiado;n=20) e Grupo 2(irradiado com 1200cGy e demarcado 2 dias após;n=20).Foi observado aumento linear do tempo de coloração do linfonodo no Grupo 2.Concluindo,a irradiação pré-operatória não influiu na demarcação do linfonodo sentinela do reto do rato / Previous ionizing radiation induces actinic alterations in peritumoral tissues and thus might influence the localization of the sentinel lymph node.The present study developed an experimental model for the localization of the sentinel lymph node of the rectum of the rat and for the definition of the dose of radiation (calibration curve).The objective was to evaluate the influence of preoperative ionizing radiation on the staining of a patent blue dye in the sentinel lymph node of the rectum in rats.The sample was composed of 40 male Wistar rats and was divided in two groups: Group 1( non-irradiated control; n = 20 ) and Group 2( irradiated with 1200cGy and stained 2 days afterwards; n = 20).It was observed a linear increase in the time for the staining of the lymph in Group 2.In conclusion, preoperative irradiation did not influence the staining of the sentinel lymph node of the rectum in rats...