对比评估双能CT、MRI定量参数对直肠癌KRAS基因突变的价值

目的 对比评估术前双能CT及MRI定量参数对直肠癌KRAS基因突变的价值,同时探讨术后病理指标与KRAS基因突变的相关性。方法 回顾性分析2017年8月至2021年4月于兰州大学第二医院经手术病理证实并行KRAS基因检测的50例直肠癌患者。根据基因检测结果分为野生型组(29例)和突变型组(21例)。纳入分析的术前临床基线资料包括性别、年龄、血清肿瘤标志物,术后病理资料包括病理分期、淋巴管血管侵犯、神经侵犯及淋巴结转移情况。三期能谱CT定量参数包括碘(水)浓度、水(碘)浓度、有效原子序数及标准化碘浓度值。表观扩散系数(ADC)定量参数包括最小ADC、平均ADC和相对ADC值。此外,分别从静脉期CT图像获得直肠上静脉宽度,从MRI图像上获得肿瘤分段、肿瘤最大轴向长度及肿瘤最大纵向长度。采用χ²检验、两独立样本t检验、Mann-Whitney U检验比较定性及定量资料间的差异。采用受试者工作特征曲线对比评估两种检查方式参数及病理指标对直肠癌KRAS基因突变的诊断效能。结果 糖类抗原199异常组较正常组具有更高的KRAS基因突变率(P=0.036)。淋巴管血管侵犯阳性组更易出现KRAS基因突变(P=0.034)。KRAS基因突变型组静脉期标准化碘浓度值高于野生型组(P=0.016),MRI参数平均ADC、相对ADC值低于野生型组(P=0.008,P=0.002),其中相对ADC的诊断效能最高(AUC=0.755)。结论 双能CT及ADC定量参数对直肠癌KRAS基因突变诊断效能相近,其中相对ADC优于其他参数。

Comparative Evaluation of the Value of Quantitative Parameters of Dual-energy CT and MRI for KRAS Mutation in Rectal Cancer

Objective To evaluate and compare the value of quantitative parameters of preoperative dual-energy CT and MRI on KRAS mutation in rectal cancer,and to explore the correlations between postoperative pathological indicators and KRAS mutation. Methods This study retrospectively analyzed 50 patients with rectal cancer confirmed by surgery and pathology and receiving KRAS genetic testing in Lanzhou University Second Hospital from August 2017 to April 2021.According to the results of genetic testing,the patients were assigned into a wild-type group (29 patients) and a mutant type group (21 patients).The preoperative baseline data included sex,age,and serum tumor markers,and the postoperative pathological data included pathological stage,lymphovascular invasion,perineural invasion,and lymph node metastasis.The quantitative parameters of three-phase energy spectral CT included iodine (water) concentration,water (iodine) concentration,effective atomic number,and normalized iodine concentration.The quantitative parameters of apparent diffusion coefficient (ADC) included minimum ADC,average ADC,and relative ADC.In addition,the width of the superior rectal vein was obtained from the CT images of the venous phase,and the tumor segmentation,the maximum axial length of tumor,and the maximum longitudinal length of tumor were obtained from the MRI images.The qualitative and quantitative data were compared by χ² test,t-test,and Mann-Whitney U test.The diagnostic efficacy of the two detection methods for KRAS mutations in rectal cancer was compared,and the receiver operating characteristic curve was employed to evaluate the diagnostic efficacy. Results The KRAS mutation rate was higher in the carbohydrate antigen 199 abnormal group than the normal group (P=0.036) and higher in the positive group of lymphovascular invasion (P=0.034).The KRAS mutant type group had higher normalized iodine concentration in the venous phase (P=0.016) and lower average ADC and relative ADC (P=0.008, P=0.002,respectively) than the wild-type group.Among them,relative ADC had the highest diagnostic efficiency (AUC=0.755). Conclusion The quantitative parameters of dual-energy CT and ADC have similar diagnostic efficiency for KRAS mutation in rectal cancer,and relative ADC is superior to other parameters.