双能量CT鉴别诊断乳腺癌肺转移瘤和肺良性结节的研究

Application of dual-energy CT in differential diagnosis of lung metastases and benign nodules in breast cancer

目的探讨双能量CT鉴别诊断乳腺癌肺转移瘤和肺良性结节的价值。方法回顾性分析2017年3月至2021年6月在温州医科大学附属第五医院经病理证实的96例乳腺癌患者资料。所有患者均在术前2周内接受双能量CT胸部扫描。96例患者均为女性, 年龄31~84(56±12)岁;共纳入207个肺结节, 根据病理结果分为肺转移瘤81个和良性结节126个。分析并测量常规CT特征[病灶最长径、边界、位置及动、静脉期结节CT值与平扫CT值的差值(ΔCT)]及双能量CT参数[动脉期、静脉期标准化碘浓度(NIC)、标准化有效原子序数(nZeff)及能谱曲线斜率(λHU)]。采用χ^(2)检验、独立样本t检验及Kruskal-Wallis秩和检验对肺转移瘤和肺良性结节的常规CT特征和双能量CT参数的差异进行分析。使用最小收缩和选择算子(LASSO)回归方法对常规CT特征、双能量CT参数进行筛选, 再行logistic回归分析最终筛选出肺转移瘤的独立危险因素。采用受试者操作特征(ROC)曲线评价单独CT参数及logistic模型鉴别肺转移瘤和肺良性结节的效能。结果肺转移瘤与良性结节的最长径及动、静脉期ΔCT、NIC、λHU和nZeff的差异均具有统计学意义(P<0.05)。经LASSO回归及二元logistic回归分析最终筛选出静脉期λHU(OR=59.413, 95%CI 14.233~248.002, P<0.001)和静脉期nZeff(OR=4.508, 95%CI 2.787~7.290, P<0.001)是预测肺转移瘤的独立危险因素。各单独CT参数鉴别肺转移瘤与肺良性结节的效能以静脉期λHU最高, 曲线下面积(AUC)为0.794, 准确度为74.88%。以静脉期λHU联合静脉期nZeff构建logistic模型鉴别肺转移瘤与肺良性结节的AUC可达0.958, 准确度为92.27%, 明显高于二者单独诊断的效能(Z=6.02、9.54, P<0.001)。结论双能量CT在鉴别乳腺癌肺转移瘤和肺良性结节中具有较大的应用价值, 当静脉期λHU联合静脉期nZeff构建logistic模型后, 其诊断效能可显著提升。

Objective To investigate the application value of dual-energy CT in the differential diagnosis of lung metastases and benign nodules in breast cancer.Methods The data of 96 patients with pathology-confirmed breast cancer at the Fifth Affiliated Hospital of Wenzhou Medical University from March 2017 to June 2021 were analyzed retrospectively.All patients received dual-energy chest CT scans within 2 weeks before surgery.All 96 patients were female,aged 31-84(56±12)years.A total of 207 pulmonary nodules from 96 patients were classified into 81 lung metastases and 126 benign nodules according to pathological findings.Conventional CT features[longest diameter,boundary,location and CT value difference between arterial and venous phases(ΔCT)of nodules]and dual-energy CT parameters[standardized iodine concentration(NIC),slope of energy spectrum(λHU)and normalized effective atomic number(nZeff)in arterial and venous phases]were analyzed and measured.Theχ2 test,independent samples t test and Kruskal-Wallis rank-sum test were used to analyze the differences of conventional CT features and dual-energy CT parameters between lung metastases and benign nodules.First,the least shrinkage and selection operator(LASSO)regression method was used to screen conventional CT features and dual-energy CT parameters,and then logistic regression analysis was performed to screen out independent risk factors for lung metastases.Receiver operating characteristic(ROC)curves were used to evaluate the efficacy of CT parameters alone and logistic model in differentiating lung metastases from benign lung nodules.Results There were statistically significant differences between lung metastases and benign nodules in longest diameter,∆CT,NIC,λHU and nZeff in arterial and venous phases(all P<0.05).LASSO regression and binary logistic regression analysis showed that the venous phaseλHU(OR=59.413,95%CI 14.233-248.002,P<0.001)and the venous phase nZeff(OR=4.508,95%CI 2.787-7.290,P<0.001)were independent risk factors for predicting lung metastases.Among them,the venous phaseλHU had the highest diagnostic efficiency,with an area under curve(AUC)of 0.794 and an accuracy of 74.88%.The AUC of the logistic model constructed by combining the venous phaseλHU and the venous phase nZeff could reach 0.958,and the accuracy was improved to 92.27%,which was significantly higher than the efficacy of the two alone(Z=6.02,9.54,all P<0.001).Conclusion Dual-energy CT has great application value in the identification of lung metastases and benign nodules in patients with breast cancer,especially when combined with venous phaseλHU and venous phase nZeff,the diagnostic efficiency is further improved.