| Objective:To analyse the differences of dual-source CT dual-energy imaging parameters between mediastinal lymph node lesions,and to appraise the value of dual-source CT dual-energy imaging in differential diagnosis of mediastinal lymph node lesions.Materials and methods:1.From March 2017 to January 2019 in the first affiliated Hospital of Guangxi Medical University,the patients with mediastinal lymph node enlargement met the following criteria:(1)no contrast medium allergy;(2)no radiotherapy or chemotherapy before CT examination;(3)it can cooperate with CT scanning.A total of 40 patients,including 34 males and 6 females,aged32-79 years and median age of(54.85 ±10.53)years,were included in the study.34 cases were pathologically confirmed,of which 9 cases were confirmed by transbronchial fine needle biopsy(3 cases of lymph node tuberculosis,3 cases of lymph node tuberculosis).Metastatic lymph nodes(n = 4),lymphoma(n = 2)There were 25 cases(1 case of lymphadenitis,2 cases of tuberculous lymph node,19 cases of metastatic lymph node and 3 cases of lymphoma).After anti-inflammatory or anti-tuberculosis treatment,the lymph nodes weresignificantly reduced in 6 cases(lymphadenitis in 5 cases,tuberculosis in 1 case).According to the pathological and clinical findings of mediastinal lymph nodes,they were divided into three groups: inflammatory lymphadenopathy group(n =12),metastatic lymph node group(n = 23)and lymphomas group(n = 5).Combined with CT images,85 lymph nodes met the criteria of grouping,of which 25 were lymphadenitis,5 were pathologically confirmed by surgical resection,and 6 were pathologically confirmed by transbronchial fine needle puncture.After treatment with anti-inflammatory or anti-tuberculosis treatment,14 of them were confirmed to be significantly reduced in lymph nodes after anti-inflammatory or anti-tuberculosis therapy.Of the 45 metastatic lymph nodes,39 were pathologically confirmed by surgical resection and 6 by bronchial fine needle aspiration.Among them,15 patients with adenocarcinoma(27 lymph nodes)and 3 patients with squamous cell carcinoma(6 lymph nodes)were diagnosed by pathology.There were 4 patients with small cell carcinoma(9 lymph nodes)and 1 patient with small cell neuroendocrine carcinoma(3lymph nodes).There were 15 lymphoma,3 nodular Hodgkin's lymphoma(10lymph nodes)and 2 diffuse large B cell lymphoma(5 lymph nodes).Lymph node short-path 1.0cm~7 The length and diameter of 5.5 cm,is 1.0 cm ~ 2 cm ~8.2 cm.2.The(Siemens Somatom definition flash),the second generation 64-layer dual-source CT scanner from Siemens,Germany,was used for scanning.The dual-energy CT-enhanced venous phase images were transmitted into the Dual-Energy software of dual-source CT.The long and short diameter of lymph node was measured on the same plane,and the iodine uptake content of lymph node was recorded at the same time.The concentration of iodine in all mediastinal lymph nodes was standardized by the concentration of iodine in theaorta.Standardized iodine concentration(normalized iodine co Ncentration,NIC)formula: standardized iodine concentration = lymph node iodine concentration /same layer aortic iodine concentration.3.This subject uses SPSS16.0 to carry on the statistical analysis to the measured data.The long and short paths,iodine concentration and standardized iodine concentration of lymph nodes in different groups were tested by normality test.If the variance of the data was homogeneous and normal distribution,one-way ANOVA was used and LSD statistical analysis was used to compare the differences between the two groups.Test level ? = 0.05.Nonparametric rank sum test was used to compare the density and enhancement of mediastinal lymph nodes.Mapping(Receiver Operating Charact of receiver operating characteristics for statistically significant Energy Spectrum CT quantitative parameters Erristic,ROC)curve,the diagnostic efficiency of mediastinal lymph node NIC was measured by the area(AUC)under the curve.When AUC > 0.5,there was statistical significance.The specificity,sensitivity and optimal diagnostic threshold of NIC for the differentiation of mediastinal lymph node were further analyzed.Results:1.There was a significant difference between metastatic lymph node group and lymphadenitis group,but there was no significant difference between lymph node group and metastatic lymph node group.2.By CT plain scan,it was found that most of the mediastinal lymph nodes were solid soft tissue shadows,metastatic lymph nodes and lymphadenitis with necrosis.In contrast enhanced CT scan,most metastatic lymph nodes showed uneven enhancement,and some of them also showed circular enhancement or uniform enhancement,while CT scan showed non-uniform enhancement in themetastatic lymph nodes and non-uniform enhancement in the metastatic lymph nodes.Lymphadenitis,lymphoma is mainly homogeneous enhancement,when the lymph node is large and necrosis,it can also be non-uniform enhancement.There was significant difference between metastatic lymph node group and inflammatory lymphadenopathy group,lymph node group and metastatic lymph node group(P < 0.05).3.The iodine concentration in the lymphadenopathy group was higher than that in the metastatic lymph node group and lymphomatous group,and the iodine concentration in the metastatic lymph node group was the lowest.There was a significant difference in the iodine concentration between the three groups in the venous phase(P < 0.05).4.There was significant difference in lymphadenopathy group,metastatic lymph node group and lymphoma group(P < 0.05),in which lymph node inflammatory transformation group and metastatic lymph node group had significant difference(P < 0.05),and there was no significant difference between lymphadenitis transformation group and metastatic lymph node group(P < 0.05).The most significant difference was found between lymph node metastasis group and lymph node metastasis group(P < 0.000).5.In this study,the standardized iodine content of iodine graph(NIC)was used as a diagnostic index to judge the benign and malignant lymph nodes in mediastinum.When NIC ? 0.287 was used as the threshold for the diagnosis of benign and malignant lymph nodes,the maximum AUC was 0.848.The differential diagnosis efficiency was the best.The specificity,sensitivity and index of AUC were 72%,86.7% and 0.587 respectively.Conclusion:1.The long and short diameters of mediastinal lymphomas were significantly higher than those of metastatic lymph nodes and lymphadenitis,lymphoma and lymphadenitis(P < 0.05).It is suggested that mediastinal lymph nodes are related to the length and short diameter of the lesion.2.There was significant difference between metastatic lymph node group and inflammatory lymphadenopathy group,lymph node group and metastatic lymph node group(P < 0.05).However,the CT density and enhancement patterns of mediastinal lymph node lesions overlap,so the accuracy of diagnosis is not high in the diagnosis of different types of lymph node lesions.3.There was a significant difference in iodine concentration and standardized iodine concentration among the three groups(P < 0.05),which was valuable for the differential diagnosis of lymph nodes of different nature in mediastinal mediastinum(P < 0.05),and there was a significant difference in iodine concentration and standardized iodine concentration among the three groups(P < 0.05).4.ROC curve analysis showed that NIC had high diagnostic value in diagnosing benign and malignant mediastinal lymph nodes.NIC could be used as an index for predicting benign and malignant mediastinal lymph nodes.When the NIC of lymph nodes is less than 0.287,the possibility of malignancy is high.It is suggested that NIC ? 0.287 should be regarded as one of the quantitative indexes for the determination of mediastinal malignant lymph nodes. |
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