DWI评价兔VX2移植瘤转移淋巴结放疗的早期疗效

DWI evaluation on early response to radiotherapy in rabbit models bearing VX2 with lymph node metastasis

目的探讨DWI对评价转移淋巴结早期放疗疗效的价值。方法建立转移性淋巴结动物模型,随机分为放疗组(16枚淋巴结)与对照组(10枚淋巴结),分别于放疗前、后第1、3、7天进行常规MR及DWI检查,测量淋巴结的体积和ADC值。对两组淋巴结ADC值采用重复测量数据的方差分析。对每个时间点两组淋巴结体积和ADC值行独立样本t检验。结果放疗组4枚淋巴结第7天出现坏死,呈长T1、T2信号,且放疗后第1天淋巴结ADC值下降(1.04±0.17)×10-3mm2/s,第3、7天逐渐升高[(1.27±0.20)×10-3mm2/s、(1.69±0.33)×10-3mm2/s]。放疗后第7天两组淋巴结ADC值差异有统计学意义(F=17.87,P<0.05),放疗后第3、7天ADC值与放疗前及放疗后第1天ADC值差异有统计学意义(P均<0.05)。结论 ADC值能用于观测动物转移性淋巴结的早期放疗反应。

Objective To observe the value of DWI in monitoring lymph node metastasis early response to radiotherapy.Methods Animal models of lymph node metastasis were divided into irradiation group（16 lymph nodes） and control groups（10 lymph nodes）.MRI and DWI were performed respectively before and 1,3,and 7 days after irradiation in all rabbits.The volumes and ADC values of lymph nodes were measured,and the variants were evaluated with repeated measures ANOV.At each time interval,the Student＇s t test was used to assess differences between two groups.Results In irradiation group,necrosis was found in 4 nodes 7 days after therapy.Necrosis revealed hypointensity on T1WI and hyperintensity on T2WI.ADC values of all nodes adopted irradiation decreased 1 day after therapy（1.04±0.17）×10-3 mm2/s,then ADC values increased gradually（[1.27±0.20]×10-3 mm2/s and [1.69±0.33]×10-3 mm2/s） 3 days and 7 days later.Significant difference of variation of ADC values between two groups present 7 days after therapy（F=17.87,P〈0.05）.In irradiation group,3 and 7 days after therapy,ADC values were significantly higher than pre-treatment and 1 day after therapy（both P〈0.05）.Conclusion ADC values can be used to observe early radiation response in animal models.