The Experimental Study On Ultrasonic Integrated Backscatter In Assessing Therapeutic Response To Radiofrequency Ablation In Rabbit VX2 Liver Tumor

Objective:To evaluate the role of ultrasonic integrated backscatter (IBS) in assessing the therapeutic response to radiofrequency ablation in rabbit VX2 liver tumor.Methods:After twenty four models of rabbit VX2 liver tumor were set up by ultrasonography-guided implantation of VX2 constitution masses,three rabbits were selected randomly to receive pathological examination. 21 rabbits VX2 liver tumors were subjected to radio frequency ablation treatment under ultrasonic guide after integrated backscatter were measured. After the treatment, 21 rabbits were divided three groups. There were 7 rabbits in every group. The IBS of the regions of interest were measured at different time points (1day, 7day and 14day, respectively). HP Sonos 5500 image system with quantitative analysis function was used for IBS measurement. With the machine setting fixed and optimal image obtained, the IBS and its changes in the rabbit liver tumor and the regions of interest were received and compared before and after the treatment. In the meantime, the peripheral blood was taken out respe- ctively before and after RFA. After that, all the rabbits were executed and pathological examination was performed.Results:1. The values standardized IBS showed significant difference before and after radiofrequency ablation at different time points(p<0.05); the values standardized IBS became higher and higher, there was significant difference between each groups(p<0.05). The IBS of the center of target was higher than that of peripheral,the values standardized IBS showed significant difference at different time points(p<0.05). The change of IBS were over 50%, can be determined necrosis by pathological examination. There was no significant difference of IBS in the normal liver of the around between the before and after RFA(p>0.05). The IBS of different organize according the go-up order was: the rabbit liver tumor, normal liver, peripheral of the target,center of the target.2. Light microscopic examination showed tumor tissue coagulative necrosis, tumor cells appeared nuclear pyknonsis, karyorrhexis and karyolysis, fibrin organi- zation was increase from the seven days.3. After RFA hepatic function changed apparently in seven days and restored gradually to the normal level in 14 days. Concrete variety: total protein(TP) and albu- min(A) obviously lowers, total bilirubin(T-BIL), ALT, AST, ALP were all increased. Besides TP, ALP, the rest index sign were all restored on about 14 days. After RFA, the kidney function analyzes was BUN and Cr increased on the 1 shorterly, in a while recovered the normal level.Conclusion:Ultrasonic integrated backscatter could assess the therapeutic response to radiofrequency ablation in Rabbit VX2 Liver tumor and heralds a new method of noninvasive quantitative measurement.