单、双指数DWI模型与肺腺癌EGFR、Ki-67表达的相关性研究

Correlation between Mono-and Bi-Exponential DWI Models and Expression of EGFR and Ki-67 in Lung Adenocarcinoma

目的探讨单、双指数DWI模型各参数与表皮生长因子受体(EGFR)基因突变状态及Ki-67表达的相关性。方法回顾性分析经病理证实且行MRI多b值DWI扫描的肺腺癌患者51例,根据EGFR基因是否突变,分为基因突变型组及野生型组,根据Ki-67指数分为高表达组及低表达组。通过MRI单指数DWI模型获得病变表观扩散系数(ADC)值,通过双指数体素内不相干运动(IVIM)模型获得D、D^(*)和f值。评估单、双指数DWI模型各参数值与EGFR基因突变状态及Ki-67指数的相关性,比较EGFR突变型与野生型组、Ki-67高表达与低表达组间各参数值的差异,绘制受试者工作特征曲线评价存在统计学相关性的参数对EGFR、Ki-67表达水平的预测效能。结果51例肺腺癌患者中,EGFR基因突变型25例,野生型26例;Ki-67高表达28例,低表达23例。D值与EGFR基因突变状态呈正相关(r=0.368,P<0.05);ADC值与Ki-67指数呈低度负相关(r=-0.298,P<0.05),D值与Ki-67指数呈中度负相关(r=-0.508,P<0.05)。EGFR基因突变型组D值高于野生型组,差异有统计学意义(P<0.05);Ki-67高表达组ADC、D值低于低表达组,差异有统计学意义(P<0.05)。D值鉴别EGFR基因突变状态的曲线下面积为0.712,当D≥1.03×10^(-3)mm^(2)/s时,倾向于EGFR基因突变。ADC、D值鉴别Ki-67高、低表达的曲线下面积分别为0.726、0.859(Z=1.979;P=0.048),当ADC<1.22×10^(-3)mm^(2)/s、D<1.06×10^(-3)mm^(2)/s时,倾向于Ki-67高表达。结论D值与EGFR突变状态呈正相关,ADC值与Ki-67指数呈低度负相关,D值与Ki-67指数呈中度负相关。因此,单、双指数DWI模型有助于临床对肺腺癌患者进行个体化评估,以双指数模型更具优势。

Objective To investigate the correlation between the parameters of mono-and bi-exponential diffusion weighted imaging(DWI)models and EGFR gene mutation as well as Ki-67 expression.Methods 51 patients with lung adenocarcinoma confirmed pathologically were retrospectively analyzed.All patients were examined by multi-b value DWI lung MRI,and were classified into EGFR mutation group and wild-type group according to whether EGFR gene mutation oc-curred,or divided into high and low Ki-67 expression groups based on Ki-67 expression levels.ADC value of the mono-ex-ponential DWI model and parameters(D,D^(*),and f)of bi-exponential DWI model(IVIM)were obtained.The correlation between the above DWI parameters and expression of EGFR and Ki-67 were evaluated,the differences of each DWI parame-ters between different EGFR mutations groups or Ki-67 expression groups were compared,and the ROC curves for evaluating the predictive efficacy of statistically correlated parameters on EGFR or Ki-67 were drawn.Results Among 51 patients with lung adenocarcinoma,25 were EGFR mutation type and 26 were wild-type,and the expression of Ki-67 was high in 28 cases and low in 23 cases.The D value was positively correlated with EGFR gene mutation status with statistic significance(r=0.368,P<0.05).There was a low negative correlation between ADC value and Ki-67 index(r=-0.298,P<0.05)and a moderate negative correlation between D value and Ki-67 index(r=-0.508,P<0.05).The D value in the EGFR mutations group was significantly higher than that in the wild type group(P<0.05).The ADC and D value of the high Ki-67 group were significantly lower than those of the low Ki-67 group(P<0.05).The D value showed a good performance in discriminating EGFR mutation group and wild-type group with an area under the ROC curve(AUC)of 0.712.When D≥1.03×10^(-3)mm^(2)/s,the diagnosis tended to be EGFR gene mutation.The AUC of ADC and D value for distinguishing high from the low Ki-67 group was 0.726、0.859,respectively(Z=1.979;P=0.048).When ADC<1.22×10^(-3)mm^(2)/s or D<1.06×10^(-3)mm^(2)/s,a diagnosis of high Ki-67 expression was preferred.Conclusion The D value was positively corre-lated with EGFR gene mutation status.There was a low negative correlation between the ADC value and Ki-67 expression and a moderate negative correlation between the D value and Ki-67 level.Therefore,mono-and bi-exponential DWI models are helpful in individualized evaluation of patients with lung adenocarcinoma,and the performance of bi-exponential DWI model was better than that of mono-exponential models.