Correlation Study Between Multi-slice CT Perfusion And Tumor Hypoxia Imaging In Rabbit VX2 Lung Cancer

Objective:To establish the model of rabbit VX2 Lung Cancer successfully,perform conventional of multi-slice CT(MSCT)plain scan and perfusion scan,immunohistochemical staining for the tumor specimen.To analyze the correspondence relationship between every parameter in MSCT perfusion imaging and the express level of tumor hypoxia marker,investigate the correlation between the CT perfusion and hypoxia imaging in Rabbit VX2 Lung Cancer.Methods:17 female New Zealand white rabbits were implanted with the VX2 tumor in lung.MSCT plain scan and perfusion scan were performed when tumor was big in the scale 1.5～2cm.With the help of perfusion 3 software(GE Medical Systems), applying the method of high space resolution,we calculated and displayed the falsecolor perfusion parameter image,which can reflect the condition of tumor tissue perfusion, blood flow(BF),blood volume(BV),mean transit time(MTT)and permeability surface(PS)mapping images were acquired.The descending aorta as inflow artery,using the blood flow three-color-image(red,green,blue)as the discriminating standard,its scale was 0-10000Hu.we used red and green scale reflecting high perfusion region,blue and other regions which lower than blue reflecting low perfusion region. In the high and low perfusion image,we select three region of interest(ROI) respectively,using their mean value as the last value of every correlation perfusion parameter.during measurement,we should avoid the regions whose blood flow were zero in perfusion image.After CT perfusion,the rabbit was sacrificed and the corresponding tumor specimen was harvested.H E staining,hypoxia,VEGF and MVD immunohistochemical staining(streptavidin peroxidase method)were carried out.Results:Established the model of rabbit VX2 Lung Cancer successfully.Performed conventional of multi-slice CT(MSCT)plain scan and perfusion scan to rabbit VX2 Lung Cancer.To compare high perfusion region and low perfusion region,using the blood flow three-color-image(red,green,blue)as the discriminating standard,The mean values of BF,BV and PS had obviously difference in statistic between high and low perfusion(F=18.2,1,1,all the P value less than 0.05).HIF-1,VEGF had obviously difference in statistic between high and low perfusion(F=28,24.7,all the P value less than 0.05).MVD had no difference between two groups(F=32,P=0.57).The result of Spearman correlation analyze in group:in high perfusion region,BV and BF,MTT have positive correlation(r=0.60539,0.54881,p=0.0100,0.0225).BF and MTT,PS have no obviously correlation(r=-0.05488,-0.17892,p=0.8343,0.4920),MTT and PS have no obviously correlation(r=0.09467,p=0.7178);in low perfusion region, BV and BF,PS have positive correlation(r=0.77206,0.77206,p=0.0003,0.0003),but have no obviously correlation with MTT(r=-0.05762,p=0.8261),BF and MTT,PS also have obviously correlation(r=-0.58373,0.62990,p=0.0139,0.0067),MTT and PS have no obviously correlation(r=0.00752,p=0.9772).HIF-1αand BV,BF all have negative correlation in statistics(r=-0.74510,-0.50000,P=0.0006,0.0410)in high perfusion region,HIF-1 and BV,BF,PS all have negative correlation in statistics in low perfusion region(r=-0.50276,-0.48804,-0.52606,P=0.0397,0.0469,0.0301),MVD and PS have positive correlation in statistics(r=0.64490,P=0.0052).the HIF-1 had negative correlation with BV both in two groups(P=0.0006,0.0397,r=-0.74510, -0.50276).Conclusion:There were obviously difference between HIF-1 and BV in statistic in high and low perfusion region.the change of blood flow would influence tumor's oxygen supply,which is a hint that high and low perfusion region of CT perfusion image have obviously correlation with hypoxia image in rabbit's lung cancer.Low perfusion region of CT perfusion image could reflect the tumor hypoxia region initially.