不同碘定量测量方式评价非小细胞肺癌EGFR突变状态:截面法vs.体积法

Assessment of EGFR Mutation Status in Patients with Non-Small-Cell Lung Cancer using Different Iodine Quantification Methods in Dual-Energy CT: Areal vs. Volumetric Analyses

目的探究最大截面法、体积法所测双能量CT碘相关定量参数,预测非小细胞肺癌(NSCLC)表皮生长因子受体(EGFR)突变的可行性,并探究二者碘定量参数之间的相关程度。方法 58例NSCLC患者于活检或手术前行动脉期双能量CT扫描。分别采用最大截面法及体积法勾画感兴趣区,获得最大截面碘浓度(ICareal)、最大截面标准化碘浓度(NICareal)以及体积碘浓度(ICvolumetric)、体积标准化碘浓度(NICvolumetric)。体积法测量中,软件进一步切割肿瘤,获取由内到外各层及各层内部的体积碘定量参数。比较EGFR突变组与野生组间碘定量参数的差异,采用受试者工作特征曲(ROC)曲线分析,获得ROC曲线下面积(AUC)、比较最大截面及体积法所测参数预测EGFR突变的效能。结果 58例NSCLC病变中,28例EGFR突变阳性,30例EGFR突变阴性。EGFR突变组NICareal(0.16±0.06)明显高于EGFR野生组(0.12±0.05)(t=2.869,P=0.006)。EGFR突变组内部及内层NICvolumetric均明显高于EGFR野生组(t=2.415~2.699,P=0.009~0.019)。但EGFR突变组与野生组之间病变整体及边缘部体积碘定量参数差异无统计学意义。ROC曲线示NICareal(AUC=0.693)的诊断效能稍高于内部及内层NICvolumetric(AUC=0.655~0.677)。NICareal与内部NICvolumetric明显相关(r=0.818~0.821)。结论最大截面及体积法所测碘定量参数均可用于预测NSCLC的EGFR突变状态,最大截面碘定量参数测量在临床应用中更简便,推荐用于临床常规评价。

Objective To investigate the feasibility of areal and volumetric iodine quantification metrics with dual-energy CT in predicting EGFR mutation status of non-small cell lung cancer(NSCLC) and the correlation between the two methods. Methods 58 untreated NSCLC patients who underwent DECT in an arterial phase before biopsy or surgery were prospectively enrolled.For each lesion, areal iodine content(IC) and normalized iodine content(NIC) at maximum area among slices and volumetric IC and NIC of the whole-tumor were evaluated by two radiologists.In the volumetric analysis, tumor was further sectioned, volumetric parameters of every segment and peel were noted.The diagnostic performances of areal and volumetric iodine metrics in characterizing EGFR mutations were compared, and the two iodine quantification methods were correlated with each other. Results EGFR mutations were found in 28 of 58 patients.NICareal of EGFR mutant group(0.16±0.06) was higher than that of wild-type group(0.12±0.05)(t=2.869,P=0.006).NICvolumetric of the inner segment and peel in EGFR mutant group were higher than that in wild-type group(t=2.415-2.699,P=0.009-0.019).However, volumetric parameters of the total lesion and marginal part showed no significant difference between the two groups.ROC curve analysis revealed that diagnostic performance of NICareal(AUC=0.693) was similar to that of NICvolumetric of inner segments and peels(AUC=0.655-0.677).NICareal was strongly correlated with inner segmental NICvolumetric(r=0.818-0.821). Conclusion Areal and volumetric iodine metrics were applicable in predicting EGFR mutation status, the maximum area iodine quantification was suggested in clinical use due to its convenient access.