The Experiment Research On Microwave Ablation For VX2 Tumor In Rabbit's Lung Guided By MRI

Aim: analyze and research the microwave ablation(MWA)for VX2 tumor in rabbit lung guided by MRI and evaluate the feasibility for the curative effect.Method: the first part: we inoculated VX2 tumor in the muscular tissue of bilateral hind leg of two male New Zealand white rabbits and if the tumor formed,it was the cell strain of VX2 tumor model of rabbit lung.We made the general anesthesia for the 12 experiment rabbits used for test and planted the tumor tissue block in rabbit lung guided by CT;after 15 days we made CT reexamination to make sure whether the tumor was formed;we observed the complete cytoreduction by using the MRI from the rabbits which had the tumor on the lung with maximum diameter of 10 mm or over 10 mm and killed an experiment rabbit randomly which had the tumor in the lung to verify the pathological mechanism.The second part: we tested the antenna order of microwave ablation guided by MRI and the setting order was fs-tse-T2 WI and 3DVibe;we inserted the microwave antenna(which was compatible with MRI)into a agar block and made the included angle between the long axis of microwave antenna and main field were 0°,30°,60°and 90° respectively;we took the long axis of microwave antenna as the center and made coronal,sagittal and axial scanning and measured the artifacts size of microwave antenna.The third part: after removing the cony hair and making general anesthesia for seven experiment rabbits which have tumors on the lung,we put them on the scanning bed of MRI;we killed the experiment rabbits after finishing the MRI scanning and took out the rabbits' lungs to make general pathology and histopathology examination.We made pairwise comparison for the maximum diameter in the high-intensity zone of complete cytoreduction on fs-tse-T2 WI before microwave ablation(MWA),the maximum diameter in the high-intensity zone of 3DVibe center after MWA,the maximum diameter in the low-intensity zone of ablation focus center on fs-tse-T2 WI after MWA and the maximum diameter of coagulative necrosis part in pathology and we made the pairwise comparison for the maximum diameter in the signal part around the complete cytoreduction on 3DVibe after MWA,the maximum diameter in high-intensity zone around the complete cytoreduction on fs-tse T2 WI and the maximum diameter in thermal damage zone in pathology.Result:The first part: among 12 experiment rabbits,9 rabbits have tumors in the lung and the tumor formation rate is 75%.8 rabbits have the single lung tumors and one rabbit has the multiple metastatic tumors with the pleural metastasis.The second part: if the included angle between the long axis of microwave antenna and main field is bigger,the artifact is bigger.If the included angle of main field is same,the artifact of 3DVibe is bigger than fs-tse-T2 WI.The third part: microwave ablation(MWA)was finished guided by MRI for seven experiment rabbits in which the VX2 tumor was planted successfully and there is no severe complication during the operation.The signal of the microwave ablation needle which is compatible with the magnetic resonance is low on MRI image.On 3DVibe the signal of the complete cytoreduction is high;the signal on fs-tse-T2 WI is low,ring signals such as T1 WI was appear nearby;high signal zone of T2 WI surround it;on DWI,the signal of complete cytoreduction is low and high signal surrounds around.After MWA,we made the pairwise comparison for the maximum diameter of central high signal area on 3DVibe,the maximum diameter of low signal area of complete cytoreduction center on fs-tse-T2 WI and the maximum diameter of coagulative necrosis part in pathology and the difference has not the statistical significance(P>0.05).We made the pairwise comparison for the maximum diameter in signal zone nearby 3DVibe after MWA,the maximum diameter in high-intensity zone nearby fs-tse-T2 WI and the maximum diameter in thermal damage zone in pathology and the difference has not the statistical significance(P>0.05).Conclusion: 1.Treating the VX2 tumor in rabbit lung,by using MWA guided by MRI is an effective minimally invasive intervention method.2.After MWA,the images on MRI form some feature which has the same scope with the ablation in gross pathology.3.MRI can provide accurate evaluation for microwave ablation(MWA)in treating the VX2 tumor in the rabbit lung.