Experimental study on angiogenesis in rabbit VX_2 brain tumor using perfusion CT

Objective:To study the perfusion CT features of rabbit VX2 brain tumor with correlation to MVD and VEGF,and to validate perfusion CT for reflection of tumor angiogenesis.Methods:Rabbit VX2 brain tumor model was established by injection of 100 μL viable tumor cells(107/mL)through a 2 mm-hole 5 mm to the right of the sagittal suture and 5 mm posterior to the coronal suture bored by dental drill.MRI was performed every 2 days after seven days of implantation to evaluate the growth of the tumor.Twenty New Zealand White rabbits with tumor size over 3 mm in diameter were randomly divided into 2 groups according to the tumor growth time with those less than 3 weeks as group 1 and those more than 3 weeks as group 2,and perfusion CT were performed accordingly.CT measurements of BV,BF and PS from tumor,peritumor and contralateral normal tissue regions were obtained.After that the animals were sacrificed and 2% Evans blue(2 mL/kg)was given intravenously in 16 of these animals 1 h prior to sacrifice to detect breakdown of the blood brain barrier.VEGF and MVD were evaluated in im-munohistochemical examination of the specimens.Results:Tumor had significantly higher BV,BF and PS(P=0.000)than peritumor and normal tissue region.Tumor BV,BF and MVD in group 2 were significantly higher than that in group 1(P<0.01).Significant linear correlation was found between MVD and BV(r=0.915,P=0.000),MVD and BF(r=0.901,P=0.000),and MVD and PS(r=0.459,P=0.042).We also found a rank correlation between PS and blue stain of tumor(rs=0.861,P=0.000).Conclu-sion:Perfusion CT can distinguish tumor from peritumor and normal tissue clearly,reflect tumor angiogenesis accurately,and provide useful information for the evaluation of brain tumor.

Objective： To study the perfusion CT features of rabbit VX2 brain tumor with correlation to MVD and VEGF, and to validate perfusion CT for reflection of tumor angiogenesis. Methods： Rabbit VX2 brain tumor model was established by injection of 100 μL viable tumor cells （10qmL） through a 2 mm-hole 5 mm to the right of the sagittal suture and 5 mm posterior to the coronal suture bored by dental drill. MRI was performed every 2 days after seven days of implantation to evaluate the growth of the tumor. Twenty New Zealand White rabbits with tumor size over 3 mm in diameter were randomly divided into 2 groups according to the tumor growth time with those less than 3 weeks as group 1 and those more than 3 weeks as group 2, and perfusion CT were performed accordingly. CT measurements of BV, BF and PS from tumor, peritumor and contralateral normal tissue regions were obtained. After that the animals were sacrificed and 2% Evans blue （2 mL/kg） was given intravenously in 16 of these animals 1 h prior to sacrifice to detect breakdown of the blood brain barrier. VEGF and MVD were evaluated in immunohistochemical examination of the specimens. Results： Tumor had significantly higher BV, BF and PS （P=0.000） than peritumor and normal tissue region. Tumor BV, BF and MVD in group 2 were significantly higher than that in group 1 （P〈0.01）. Significant linear correlation was found between MVD and BV （t=-0.915, P=-0.000）, MVD and BF （t=0.901, P=-0.000）, and MVD and PS （t=-0.459, P=0.042）. We also found a rank correlation between PS and blue stain of tumor （rs=0.861, P=0.000）. Conclusion： Perfusion CT can distinguish tumor from peritumor and normal tissue clearly, reflect tumor angiogenesis accurately, and provide useful information for the evaluation of brain tumor.