Multimodality CT Imaging Technology For Diagnosis Of Metastatic Lymph Nodes In Gastric Cancer

Part 1 Diagnostic Value of Multislice Spiral CT Perfusion Imaging in Metastatic Lymph Nodes of Gastric CancerObjective:To explore the diagnostic value of Toshiba 320-slice CT perfusion imaging in metastatic lymph nodes of gastric cancer.Methods:From November 2018 to November 2019,29 patients with gastric cancer confirmed by gastroscopy in the affiliated hospital of Chengde medical college were collected.90 suspected metastatic lymph nodes were obtained with a short diameter ? 5 mm.after informed consent of the patients,Toshiba 320-row dynamic volume CT was used for plain scan+enhanced scan and perfusion examination.the scanning conditions of different patients were the same.After image post-processing,the perfusion pseudocolor map of the "target" lymph node and the perfusion parameter values are obtained.The parameters include: blood flow(AF),Blood Volume(BV)and vascular surface permeability(PS).Postoperative pathology confirmed 46 metastatic lymph nodes and 44 non-metastatic lymph nodes.According to pathological results,the "target" lymph nodes were divided into metastatic group and non-metastatic group.The perfusion parameters of lymph nodes of metastatic group and non-metastatic group were compared.ROC curve analysis was performed on perfusion parameters affecting diagnosis and truncation values were calculated.Results:Arterialflow(AF)and vascular surface permeability(PS)in metastatic lymph node group are higher than those in non-metastatic lymph node group,with significant difference and statistical significance(P ? 0.01).The area under ROC curve of PS is the largest,so the diagnostic efficiency of PS is better than AF in evaluating metastatic lymph nodes of gastric cancer.The optimal critical value of PS is 37.8ml/100 ml,the sensitivity is 89.1%,and the specificity is 68.2%.Conclusion:The AF value and PS value of CT perfusion parameters can evaluate the metastasis of gastric cancer lymph nodes in gastric cancer patients,and provide reference basis for clinical selection of treatment scheme and prognosis of gastric cancer patients.Part 2 Diagnostic Value of CT Perfusion Imaging Combined with CT Plain Scan,Three-phase Enhanced Scan and MPR Multimodality Imaging in Metastatic Lymph Nodes of Gastric CancerObjective:To explore the diagnostic value of CT perfusion imaging combined with CT plain scan,three-phase contrast enhancement and MPR in comprehensive evaluation of metastatic lymph nodes in gastric cancer patients.Methods:Analysis of 90 suspected metastatic lymph nodes in 29 patients with gastric cancer,divided into three groups according to the examination method: conventional CT examination(including CT plain scan and enhancement,MPR),CTPI,conventional CT + CTPI examination technology).CTPI examination uses AF and PS values to determine whether lymph node metastasis;routine CT examination diagnostic indicators: short-length-diameter ratio ?0.7,plain scan ct value ?25HU or enhanced scan venous phase ?75 HU(mild to moderate enhancement);or above No,but lymph node fusion occurred;routine CT examination + CTPI examination,comprehensive analysis of the above indicators.Two experienced deputy chief physicians engaged in CT diagnosis used double-blind method to analyze and diagnose the obtained images and parameters.Results:Among the 90 suspected metastatic lymph nodes,the diagnostic accuracy rates of CT routine examination,CTPI,CT routine examination +CTPI were 76.7%(69/90),75.6%(68/90),91.1%(82/90),and Kappa values were 0.532,0.508,and 0.822 respectively.Among them,the contrast between CT routine examination and CT routine examination +CTPI examination(?2 =6.947,P=0.008),CT routine examination +CTPI examination and CTPI(?2 =7.840,P=0.005)has significant difference in the diagnostic accuracy rate of lymph node nature(p ? 0.05).The diagnostic specificity of CT routine examination,CTPI,CT routine examination +CTPI for metastatic lymph nodes of gastric cancer were 72.7%(32/44),72.2%(29/44)and 90.9%(40/44),respectively.Among them,the contrast between CT routine examination and CT routine examination +CTPI examination(?2 =3.773,P=0.048),CT routine examination +CTPI examination and CTPI(?2 =6.715,P=0.010)has significant difference in the diagnostic accuracy of lymph node nature,with statistical significance(p ? 0.05).The sensitivity of the three groups to the evaluation of metastatic lymph nodes in gastric cancer was 80.4%,84.8%,and 91.3%,respectively.There was no difference between the three groups(P> 0.05).Conclusion:CTPI combined with CT plain scan and three-phase enhancement,MPR multi-modality CT imaging technology has better diagnostic value for the diagnosis of gastric cancer lymph node nature,and has higher accuracy for the detection of benign lymph nodes,which can provide more accurate imaging basis for clinical preoperative staging and postoperative examination.