PET/CT Imaging In Rabbit Models Of Liver VX₂ Tumor And The Correlation With CT Perfusion: Experimental Study

ObjectiveTo investigate the imaging characteristics of the rabbit models of liver VX₂ tumor on PET/CT imaging.To investigate the imaging characteristics of the rabbit models of liver VX₂ tumor on ¹⁸F-FDG PET/CT imaging and the correlation between ¹⁸F-FDG uptake and the expression of glucose transporter type 1(GLUT1),proliferating cell nuclear antigen(PCNA).To prospectively determine the relationship between hepatic tumor blood flow and glucose utilization in vivo by using the positron emission tomography(PET)and computed tomography(CT)perfusion technology.Materials and Methods1.Thirty New Zealand rabbits were included in the study and VX₂ tumor piece was implanted directly into the liver after laporotomy.¹⁸F-FDG PET/CT scan was performed on the seventh,fourteenth,twenty-first,twenty-eighth and thirty-fifth day after implantation.Visual evaluation and the average standardized uptake value (SUVavg),the maximum standardized uptake value(SUVmax)were analyzed quantitatively.¹⁸F-FDG PET/CT scan was performed on the seventh,fourteenth, twenty-first,twenty-eighth and thirty-fifth day after implantation.Visual evaluation and the maximum standardized uptake value(SUVmax)were analyzed quantitatively.2.Fifteen VX₂ tumor samples were studied by pathological and immunohistological examination in the tumor and the normal liver parenchyma.The expression indices of GLUT1,PCNA in all the samples were recorded and their correlations with corresponding SUVavg value were analyzed.3.Functional CT and PET scan were performed before tumor implantation and every 7 days thereafter.The weighted summation of the aortic and portal venous time attenuation curves was deconvolved against curves from the liver to derive hepatic blood flow(HBF).FDG uptake was measured as standardized uptake value(SUV). Data were analyzed with repeated-measures analysis of variance and the Tukey-Kramer multiple comparison test.Linear regression was used to compare SUV and HBF in tumors and normal tissue.Results1.For liver VX₂ tumor there was intense FDG uptake on PET imaging and PET imaging can provide good contrast between liver VX₂ tumor and normal liver tissue.In the corresponding region CT depicted a low attenuation area,and on fused ¹⁸F-FDG PET/CT image the focus can be visualized clearly and localized accurately.The distinction of tumor SUVavg between VX₂ tumor and normal liver was significant(t= 3.991,P＜0.01).¹⁸F-FDG uptakes by the VX2 liver tumors were 1.8 times higher than that by the normal liver tissue.For liver VX₂ tumor there was intense FDG uptake on ¹⁸F-FDG PET/CT imaging and ¹⁸F-FDG PET/CT imaging can provide good contrast between liver VX₂ tumor and normal liver tissue.In the corresponding region CT depicted a low attenuation area,and on fused ¹⁸F-FDG PET/CT image the focus can be visualized clearly and localized accurately.The distinction of tumor SUVmax between VX₂ tumor and normal liver was significant(t=3.659,P＜0.01).¹⁸F-FDG uptakes by the VX2 liver tumors were 1.8 times higher than that by the normal liver tissue.2.There were correlations between the expression indices of GLUT1 or PCNA and the corresponding SUVmax,r is 0.794 and 0.867 respectively,P＜0.01.3.In the hypo vascular tumor core,(a)mean HBF decreased from 225.12ml/min·100g±16.03(standard deviation)at baseline to 113.34 ml/min·100g±50.18 at the end of the study(P＜0.05)and(b)mean SUV increased from 1.78g/ml±0.49 to 2.86g/ml±1.03(P＜0.05)during the same period.ConclusionsThe VX₂ tumor can be visualized clearly and evaluated on ¹⁸F-FDG PET/CT imaging.The VX₂ tumor can be visualized clearly and evaluated on ¹⁸F-FDG PET/CT imaging.There was a good correlation between ¹⁸F-FDG uptake and the expression indices of GLUT1 or PCNA in liver VX₂ tumor.SUV reflects the metabolism and proliferation of the VX₂ tumor,indicates the grade malignancy.The positron emission tomography(PET)and computed tomography(CT)perfusion technology can be used to observe changes in HBF and glucose utilization in a growing liver VX2 tumor.