| Objective:Using the second generation of 64 Germany Siemens layer dual source CT scanner to double energy scanning of lung cancer with mediastinal metastasis lymph nodes in different enery X-ray attenuation trend changes,by analyzing the spectrum curve mediastinal lymph nodes,and to explore dual source CT spectrum curve and normalized iodine concentration in lymph node metastasis of lung cancer diagnosis.Materials and methods:1.Between March 2013 and February 2015,42 consecutive patients(29 men,13 women;age range,36～79 years;mean age,57.36years)with definite masses who were detected by Chest X-ray or plain CT scanning were chosen to perform DSCT perfusion scanning.None of the patients had been treated with anticancer drugs before DSCT perfusion scanning and surgery.All the patients received the DSCT perfusion scanning with one to two week before surgery.And all lesions were confirmed by pathologic examination after surgical resection.The clinical document(including operating record,histological report,and situations of lymphatic involvement)is integrated.Lymph nodes 74(lung cancer metastasis lymph node 33,non-metastasis lymph nodes 41).All patients with pulmonary carcinoma were classified into two group according to the pathologic reports:lung cancer patients with lymph node metastasis in 17 cases(33 lymph nodes metastasis),8 cases of adenocarcinoma patients(15 lymph nodes),7 cases of squamous cell carcinoma(12 lymph nodes),small cell neuroendocrine carcinoma in one patient(2 lymph nodes),large cell neuroendocrine carcinoma in one patient(4 lymph nodes)and lung cancer without lymph node metastasis in patients with 25 cases(41 without metastasis lymph nodes,set in the control group),including 10 cases of adenocarcinoma,squamous cell carcinoma in 9 cases,glandular scales one case of cancer,alveolar carcinoma patients one case,two cases of carcinoid patients,patients with small cell neuroendocrine carcinoma in 2 cases.2.Using the second generation of Germany Siemens 64 storey dual-source CT scanner(Siemens Somatom definition definition flash)scan,the dual-energy image enhancement scanning incoming Siemens dual-source CT Special Dual-Energy software,observed on pulmonary venous phase single energy image doors and mediastinal lymph nodes,choose to obtain pathological lymph nodes,lymph measuring at the same level,the short diameter and a single energy CT image value,while recording lymph iodine content;all mediastinal lymph iodine concentration of iodine concentrations normalized by the aorta.Normalized iodine concentration(NIC)formula:=lymph standardized iodine concentration of iodine concentration/layer of the aorta with iodine concentrations.3.Statistical analysis:using SPSS 16.0 software to different groups of lymph nodes under 40～190keV every 10 kev CT value of iodine and NIC analysis.If the data conforms to normal distribution and equal variance by two independent samples t-test analysis with metastasis lymph nodes in different between the groups with and non-metastasis lymph nodes kev CT value are compared in pairs,comparative inspection level P=0.05.By all of mediastinal lymph nodes NIC and pathological condition to calculate the index of the receiver-operating characteristics(Receiver Operating Characteristic,ROC)curve.Was obtained for determining whether mediastinal lymph node metastasis of NIC diagnosis threshold.Rusults:1.The group of 42 cases of lung cancer,according to the lymph short diameter>1cm as a criterion of lymph node metastasis,the correct diagnosis of 27 lung cancer lymph metastasis,26 without lung cancer lymph node metastasis;missed six lymph nodes(no mediastinal lymph nodes),Misdiagnosis of 15 lymph nodes(pathologically confirmed reactive hyperplasia,lymph diameter>1cm).Its diagnostic sensitivity of 64.3%(27/42)and a specificity of 81.3%(26/32),the rate was 71.6%(53/74);positive predictive value of 81.8%(27/33),and negative predictive value of 63.4%(26/41).2.We observe under different keV single energy image,and make the image contrast,CNR observed that the best single lymph for 70keV energy image.42 cases of lung cancer patients,33 of lung cancer metastatic lymph node short diameter of about 0.4～2.97cm,6<1.0cm,27 ≥ 1.0cm.Most images on a single energy density is lower lung cancer metastatic lymph.41 lung cancer without lymph metastasis short diameter 0.5～1.78cm,high image density on a single energy.3.Lung cancer with lymph node metastasis and without lymph node metastasis keV value line spectrum curve trend is roughly same,to gradual decline of the curve,with the increase keV,the curve gradually flattening,that both the first half of the energy curve(40keV～140keV)Traveling steep,the difference is large;the second half of(140keV～190keV)walk line is smooth,the difference is small.4.This group of lung cancer with lymph node metastasis and without lymph node metastasis CT value difference at 40keV～90keV interval was statistically significant(P<0.05),the difference between the maximum value 40keV under CT;at 100keV～190keV range of lung cancer with lymph.node metastasis CT value difference between groups with and without lymph node metastasis was not statistically significant(P>0.05).5.Group with lymph node metastasis and without lymph node metastasis group both in the venous phase of NIC was statistically difference(P<0.05).6.In this study,as judged by NIC indicators of lung cancer lymph node metastasis,and when to NIC ≤ 0.14135 mg/dL for judging lymph node metastasis of lung cancer diagnostic threshold,its largest AUC was 0.87,the highest performance differential diagnosis at this time,the diagnostic sensitivity was 81.3%,a specificity of 83.3%,the symbol rate is 82.4%.Conclusion:1.lung cancer with lymph node metastasis and without lymph node metastasis NIC differences were statistically significant(P<0.05);lung cancer lymph metastasis group NIC value is low,no lymph metastasis group of high value NIC.2.lung cancer with lymph node metastasis and without lymph node metastasis was statistically significant(P<0.05)CT value of the difference between any two at 40keV／90keV range,at 40keV next biggest difference.3.Analysis to determine NIC lymph node metastasis of lung cancer have a higher diagnostic value,NIC can be used to determine preoperative predictors of lymph node metastasis in lung cancer use ROC curves.When lymph nodes NIC≤ 0.14135 mg/dL,strongly suggesting the possibility of lymph metastasis.Recommend quantitative indicators will focus NIC ≤0.14135 mg/dL as strongly suggestive of lung cancer lymph metastasis. |
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