双层探测器光谱CT定量参数对胃癌区域淋巴结转移的诊断价值

Diagnostic Value of Quantitative Parameters of Dual-Layer Spectral Detector CT in Regional Lymph Node Metastasis of Gastric Cancer

目的 探讨新型双层探测器光谱CT的碘浓度(IC)与有效原子序数(Zeff)鉴别胃癌区域淋巴结性质的价值。资料与方法 回顾性收集2021年5月—2022年9月广州中医药大学第二附属医院经手术病理证实且术前行光谱CT双期增强检查的108例胃癌患者(转移淋巴结116枚、非转移淋巴结92枚)的影像及临床资料。根据术前CT图像,测量淋巴结短径、评估边缘及强化均匀度。勾画目标淋巴结最大层面的实性部分,获得IC与Zeff,并计算标准化IC(nIC)及标准化Zeff(nZeff)。比较两组间各参数的差异;分析各参数鉴别诊断和联合诊断的效能;比较各参数的受试者特征曲线下面积(AUC)。结果 两组间短径、边缘、强化均匀度差异均有统计学意义(t/χ2=-7.575、30.971、20.913,P均<0.001)。良性淋巴结组动脉期各光谱参数均小于恶性组,静脉期各参数均大于恶性组(t=-10.723~12.610,P均<0.001)。3个常规特征中,短径的AUC最高(0.749),与动脉期IC和静脉期Zeff的AUC差异无统计学意义(P>0.05),但低于其他光谱参数。光谱参数中,静脉期nIC的AUC最高(0.925)。各光谱参数的敏感度与特异度均高于常规特征。多参数联合模型的诊断效能优于单变量模型,常规特征的联合模型AUC为0.815,光谱参数联合模型中,动静脉期参数联合模型的诊断效能最高(AUC=0.993)。结论 双期光谱CT定量参数可有效评估胃癌区域淋巴结性质,且诊断效能高于常规特征,多参数联合模型可提升诊断效能。

Purpose To explore the value of iodine concentration(IC) and effective atomic number(Z_(eff)) derived from dual-layer spectral detector CT in diagnosing the regional lymph nodes of gastric cancer. Materials and Methods From May 2021 to September 2022, 108 patients pathologically confirmed with gastric cancer(92 non-metastatic lymph nodes and 116 metastatic lymph nodes), who underwent dualphase enhanced dual-layer spectral detector CT scanning preoperatively in the Second Affiliated Hospital of Guangzhou University of Chinese Medicine, were included in the study. The imaging and clinical data of all cases were collected, retrospectively. According to preoperative CT images, the short diameter, margin and enhancement homogeneity of the lymph nodes were evaluated. The IC and Z_(eff) were obtained from the delineated region of interest of the solid portion of the maximum layer of the target lymph nodes, and the normalization IC(nIC) and normalization Z_(eff)(nZ_(eff)) were calculated. The difference of parameters between two groups were compared. The efficiency of differential diagnosis and combined diagnosis of each parameter was analyzed. The area under the receiver characteristic curve(AUC) for each parameter were compared. Results There were statistical differences in short diameter, margin and enhancement homogeneity between the two groups(t/χ^(2)=-7.575, 30.971, 20.913, all P<0.001). In the benign lymph nodes group, all spectral parameters in the arterial phase(AP) were lower than those in malignant lymph nodes, while the parameters in the venous phase(VP) were higher(t=-10.723-12.610, all P<0.001). Among the three conventional features, the AUC of short diameter was the highest(0.749). Compared with the AUC values of ICAP and Z_(eff)VP, the AUC values of short diameter and quantitative parameters had no statistical difference(P>0.05), but were lower than those of other spectral parameters. Among the spectral parameters, the AUC value of nICVP was the highest(0.925). The sensitivity and specificity of the spectral parameters were higher than those of conventional features. The diagnostic efficacy of the multi-parameter combined model was superior to that of the univariate model. The AUC value of the combined model with conventional features was 0.815. Among the combined model based on CT spectral parameters, the diagnostic efficacy of model combined with the parameters of arteriovenous phase was the highest(AUC=0.993). Conclusion The quantitative parameters of dual-phase enhancement derived from dual-layer spectral detector CT can effectively evaluate the characteristics of gastric cancer regional lymph nodes, and the diagnostic efficiency is higher than the conventional characteristics of lymph nodes. The multi-parameter combined model can improve the diagnostic efficiency.