Application Of Magnetic Resonance Diffusion Kurtosis Imaging (MRI-DKI) To Observe The Effects Of Radiotherapy On Esophageal Cancer In Animal Experiments

Part one An animal experimental study of the effect of radiotherapy on esophageal cancer by diffusion weighted imaging(MR-DKI)Objective: To investigate the application value of DKI in predicting the curative effect of esophageal cancer radiotherapy from the aspect of animal model,and to provide a theoretical basis for its rational application in clinic.Methods: Forty nude mice(Eca-109)were randomly divided into experimental group(24)and control group(16).The experimental group was given 6MV-X line 15 Gy single dose radiation therapy.The control group did not undergo any treatment.The nude mice of both groups were under anesthesia on the first day before radiotherapy in the experimental group and after 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29 after radiotherapy Days were performed on T1 WI,T2WI,and multiple b-value DWI scans.The tumor volume,ADC value,MD value and MK value were compared between the two groups.Result:1.The tumor volume in the control group doubled on the 5th day after radiotherapy,and on the 17 th day in the experimental group.There was no significant difference in the volume of V0 between the two groups on the 1st day before radiotherapy(P=0.282).The volume of the transplanted tumors on the 1st and 3rd day after radiotherapy was approximately equal,and the tumor volume in the control group was slightly larger than the experimental group on the 5th day.However,there was still no statistical difference(P=0.320).From the 7th day after radiotherapy,the tumor volume in both groups began to show significant difference,and the volume of the transplanted tumor in the experimental group was significantly smaller than that of the control group(P<0.05).2.ADC values of transplanted tumors in experimental group decreased on the 1st day after radiotherapy,rapidly increased on the 3rd day,and reached the highest point on the 7th day.Since then,the ADC value gradually decreased and remained stable on the 17 th day.And it is similar to the pre-treatment level.In the control group,the ADC value of transplanted tumors in nude mice gradually decreased from the first day and kept at a low level from the 9th day.3.The MK value of the transplanted tumor in nude mice in the experimental group began to decline on the first day after radiotherapy and reached the lowest point on the 9th day.Afterwards,the MK value gradually increased and rose to the pre-treatment level after the 17 th day,after which it was basically stable in the treatment.Before the slightly higher level.The MK value in the control group gradually increased from the first day and remained at a high level since the 17 th day.4.The trend of the MD value of transplanted tumor in nude mice was similar to that of ADC.The results of this study showed that the MD value of the xenograft tumors of the experimental group decreased slightly in the experimental group on the first day after radiotherapy,rapidly increased on the third day,peaked on the seventh day,and gradually decreased after the seventh day,until the first 19 days.Stay at a more stable and slightly higher level than before treatment.The MD value of the transplanted tumor in the control group gradually decreased from the first day to the lowest point on the9 th day,and then rose slightly and remained at a slightly lower level than before treatment.Part two Study on the Correlation of MRI diffusion kurtosis imaging with AQP expression in esophageal carcinomaObjective: To study the expression of AQP in esophageal cancer xenografts before and after radiotherapy and to investigate whether there is a correlation between AQP and ADC values,MD values and MK values,andhow they affect the changes of DKI parameters.Methods: 84 Eca-109 nude mice models were prepared.Seven time points(1 day before radiotherapy and 1st,3rd,5th,7th,15 th,and 29 th after radiotherapy)were selected according to the results of previous experiments..Real-time fluorescence quantitative PCR(RT-PCR)was used to detect the expression of AQP in the transplanted tumors of esophageal carcinoma.Western blot was used to detect the expression of AQP3 before and after radiotherapy in esophageal carcinoma and the level of gene and protein.The correlation between AQP3 expression and ADC,MK,and MD was analyzed.Result:1.RT-PCR results showed that the relative expression of AQP3 gene in esophageal carcinoma tissue was relatively high,and the relative expression of AQP3 gene began to decrease on the first day after radiotherapy,and then decreased to the lowest point on the fifth day.Gradually rise and stay at a higher level.2.Western-Blot results showed that there was no significant difference in the relative expression of AQP3 protein on the 1st day before radiotherapy and on the 1st and 29 th day after radiotherapy(P=0.868,0.337,0.228).The relative expression levels of AQP3 protein in the two groups after 3rd,5th,7th,and15 th days of radiotherapy had statistically significant differences(P<0.05).The relative expression of AQP3 protein in the experimental group began to decrease on the first day after radiotherapy and decreased to the lowest on the7 th day.The expression level increased on the 15 th day and rose to the level of the pre-treatment level at the last observation point.The AQP3 protein in the control group The relative expression increased from the first day after radiotherapy to the highest point on the seventh day after radiotherapy and remained at a higher level thereafter.3.The expression of AQP3 on the two levels before and after radiotherapy was correlated with MK value,MD value and ADC value(P<0.05),that is,ADC value and MD value were negatively correlated with AQP3 gene expression level;MK value was AQP3 gene expression levelswere positively correlated.The ADC values and MD values were negatively correlated with the AQP3 protein expression levels;the MK values were positively correlated with the AQP3 protein expression levels.Conclusion:1.This study demonstrates from the animal model that a single high-dose radiation therapy can inhibit tumor growth in tumor-bearing nude mice,and ADC,MD,and MK values can change prior to tumor morphological changes.Compared with ADC,MD values With the same sensitivity and specificity as the former,MR diffusion kurtosis imaging technology has the value of early prediction of the effect of radiotherapy on esophageal cancer.2.There was a significant difference in the expression of AQP3 between esophageal cancer and radiotherapy before and after radiotherapy.The expression of AQP3 was weakly correlated with ADC,MD,and MK.It was speculated that the mechanism of DKI in predicting of the effect of radiotherapy on esophageal cancer may be related to the expression of AQP3.