磁共振扩散峰度成像预测食管癌放疗敏感性的实验研究

Experimental study of diffusion kurtosis imaging in predicting radiotherapy sensitivity of esophageal carcinoma

目的从动物模型层面探讨扩散峰度成像(DKI)在预测食管癌放疗敏感性方面的应用价值。方法建立人食管癌Eca-109裸鼠移植瘤模型,实验组给予单次剂量15Gy(6MVX射线)照射,对照组不接受任何处理。比较两组移植瘤体积及表观弥散系数(ADC)、平均扩散峰度(MK)、平均扩散系数(MD)的变化情况,观察实验组与对照组在相应时间点的细胞密度和坏死比例。结果实验组裸鼠移植瘤在照射后明显出现了生长延迟现象,从照后第7天开始实验组移植瘤体积明显小于对照组(t=3.206~6.149,P<0.05)。照后第3天开始实验组ADC值及MD值明显高于对照组,MK值明显低于对照组(tADC=-11.018^-2.049,tMD=-6.609^-2.052,tMK=2.492~9.323,P<0.05)。照后第3天开始对照组细胞密度高于实验组,实验组的坏死比例高于对照组(t密度=-8.387^-2.239,t坏死比例=2.980~17.430,P<0.05)。结论单次大剂量照射可以抑制荷瘤裸鼠肿瘤生长,ADC、MK、MD值均可以先于肿瘤形态学变化而发生改变,移植瘤细胞密度及坏死比例的变化与ADC、MK、MD值的变化基本吻合。DKI具有早期预测食管癌放疗敏感性的价值。

Objective To explore the value of diffusion kurtosis imaging(DKI)in predicting radiotherapy sensitivity of esophageal cancer from the animal model level.Methods BALB/c nude mice were subcutaneously injected with Eca-109 cell lines to form xenograft tumors.The tumors received a single dose of 15 Gy(6 MV X-rays)in the experimental group or had no any treatment as control.The volume of transplanted tumor,the change of ADC,MK and MD values,and the tumor cell density and necrosis ratio of these two groups were observed at the corresponding time points.Results The growth of xenograft volume in the experimental group was suppressed and it was significantly smaller than that in the control group(t=3.206-6.149,P<0.05)at the 7th day after radiotherapy.From the 3rd day after radiotherapy,the ADC and MD values of the experimental group were significantly higher than those of the control group,and the MK values was lower than those in the control group(tADC=-11.018--2.049,tMD=-6.609--2.052,tMK=2.492-9.323,P<0.05).Meanwhile,the tumor cell density of the control group was higher than that of the experimental group,and the proportion of necrosis in the experimental group was higher than that in the control group(tdensity=-8.387--2.239,tnecrosis=2.980-17.430,P<0.05).Conclusions A single large dose radiation could inhibit the growth of xenograft.ADC,MK,MD values changed at the early stage prior to morphological changes of tumor in consistent with the change of cell density and necrosis ratio.DKI has the potential value in predicting radiotherapy sensitivity of esophageal carcinoma.