Diagnostic Value Of Ultrasonography In Airway Ultrasonography In Mediastinal Lymph Node Metastasis Of Lung

BackgroundLung cancer is one of the malignant tumors in the world with the highest incidence and mortality. It has become the main cause of tumor related death in the world. In china, the mortality of lung cancer has increased rapidly in the past few decades.Although the level of diagnosis and treatment of lung cancer in the past 20 years has greatly improved, the 5 year survival rate of lung cancer is still less than 15%.Accurate TNM staging of lung cancer is very important for the treatment and prognosis of the disease. Only some of the very early stage patients may appear to have more than 15% five year survival rate. The mediastinal stage was closely related to survival rate of the patients with lung cancer. In addition, the selection of the best treatment plan, the screening of clinical drug trials, and the evaluation of therapeutic effect were established on the basis of accurate mediastinal staging. Therefore, the researchers have been exploring accurate mediastinal staging tool. Endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA)has been widely used in the staging and diagnosis of lung cancer. However, in metastatic lymph nodes may have multiple pathological conditions such as necrosis, liquefaction, coexistence of benign and malignant and biopsy of lymph nodes can only represent the local lesion, the diagnostic accuracy of EBUS-TBNA is limited. Based on the important role of EBUS-TBNA in the staging of lung cancer, how to improve the accuracy of EBUS-TBNA attracts the attention of scholars.Ultrasound elastography is a new ultrasonic diagnostic technique developed in recent years. It can measure the elasticity of the tissue and reflect the hardness of the lesion. We can judge the nature of the lesion by analyzing the hardness of the lesion. Ultrasound elastography is applied widely in clinic, mainly used in differentiation nature of lesions in breast, prostate, thyroid and other superficial organs. The results show that the hardness of the malignant lesions is increased. Malignant lesions can be identified by the hardness characteristics. Endoscopic ultrasound elastography is mainly used in the diagnosis of digestive system diseases. It is highly sensitive and specific for the diagnosis of pancreatic masses and malignant lymph nodes. However, whether or not EBUS elastography can be used for the non-invasive discrimination of benign and malignant thoracic lymph nodes and lung lesions as a guide for EBUS-TBNA remains unknown. The purpose of this study is to assess the value of EBUS elastography in diagnosing mediastinal and hilar lymph node metastases and lung lesions. Elastography was performed on 68 mediastinal lymph nodes and 57 lung masses. By analysis of elastic score, strain ratio and comparing with conventional ultrasound imaging features, we explore the application value of EBUS elastography in the diagnosis of lung lesions and mediastinal lymph nodes.Chapter 1 Value of endobronchial ultrasound elastography in the diagnosis of mediastinal and hilar lymph node metastasis in lung cancerobjective1.To study the feasibility of endobronchial ultrasound (EBUS) elastography in the diagnosis of mediastinal and hilar lymph node metastasis.2.To investigate the diagnostic value of EBUS elastography for mediastinal and hilar lymph node metastasis in lung cancers.MethodsFrom January 2014 to June 2015,40 patients suspected of lung cancer were enrolled, and a total of 68 lymph nodes were evaluated by EBUS-guided transbronchial needle aspiration (EBUS-TBNA). EBUS-guided elastography of lymph nodes was performed prior to EBUS-TBNA. Standard EBUS characteristics were also described. Pathological determination of malignant or benign lymph nodes was used as the gold standard for this study. Comparisons of elastography and standard EBUS characteristics were made between benign and malignant lymph nodes.Results(1)The significant indicators of standard EBUS in diagnosis of malignant lymph nodes were hypoechonic nodes, uneven echo, distinct boundary and short diameter greater than 1cm(P<0.01).(2)The elastosonography grading score had significant differences between benign and malignant lymph nodes(P<0.01).Elastography grading score was more sensitive and specific in determining malignant lymph node than standard EBUS criteria. The receiver operating characteristic curve(ROC) for the elastography grading score showed an area under the curve(AUC) of 0.852. The best cut-off point of the strain grading score for differentiating malignant from benign lymph nodes was 2.5. The elastography grading score had a sensitivity of 85.7%, specificity of 76.9%, positive predictive value of 85.7% and negative predictive value of 76.9% for distinguishing malignant from benign nodes. The overall accuracy of elastography grading score was 82.3%. The combination of elastography grading score,low echo,distinct boundary and short diameter greater than 1cm had the best diagnostic efficiency value. The AUC for ROC for combined index was 0.911. The sensivity,specificity,positive predictive value, negative predictive value and accuracy for distinguishing between malignant and benign nodes of combined index were 88.1%,84.6%,90.2%,81.5% and 86.8%.(3) Elastography strain ratios showed significant differences between benign and malignant lymph nodes(87.69±49.15 VS 20.60±17.14) (P=0.000). The strain ratio of malignant and benign lymph nodes positively correlated with the elastography grading score (r=0.561, P=0.000).The elastography strain ratio was more sensitive and specific for determining malignant lymph nodes than elastography grading score or standard EBUS criteria. The receiver operating characteristic curve(ROC) for the elastography strain ratio showed an area under the curve(AUC) of 0.933. The best cut-off point of the strain ratio for differentiating malignant from benign lymph nodes was 32.07. The elastography strain ratio had a sensitivity of 88.1%, specificity of 80.8%, positive predictive value of 88.1% and negative predictive value of 80.8% for distinguishing malignant from benign nodes. The overall accuracy of elastography strain ratio was 85.3%.Conclusions1. EBUS elastography can be effectively used to predict mediastinal and hilar lymph node metastases in lung cancer. This non-invasive technique may thus complement standard EBUS and help guide EBUS-TBNA procedures.2. The elastography strain ratio was more sensitive and specific for determining malignant lymph nodes than elastography grading score or standard EBUS criteria.Chapter2 Value of endobronchial ultrasound elastography in the diagnosis of central lung lesionsobjectiveTo assess the value of endobronchial ultrasound elastography in the diagnosis of central lung lesions.MethodsA total of 57 patients with central lung lesions underwent ultrasonic bronchoscope examination. Elastography and standard Endobronchial ultrasound (EBUS) of lung lesions were performed before EBUS-guided transbronchial needle aspiration (EBUS-TBNA).We compared the elastography characteristics between benign and malignant lung lesions. Comparison of the diagnosis accuracy in malignant lung lesions between elastography and standard EBUS was also made.Results(1)The significant indicators of standard EBUS in diagnosis of malignant lung lesions were hypoechonic lesions, uneven echo, distinct boundary and air bronchogram (P<0.01).(2)The elastosonography grading score and strain ratio (SR) had significant differences between benign and malignant lung lesions(P<0.01).(3) The SR was more sensitive and specific for determining malignant lung lesions than elastography grading score or standard EBUS criteria. The receiver operating characteristic curve(ROC) for the elastography strain ratio showed an area under the curve(AUC) of 0.841. The best cut-off point of the strain ratio for differentiating malignant from benign lung lesions was 9.785. The elastography strain ratio had a sensitivity of 83.4%, specificity of 76.2%, positive predictive value of 86.1% and negative predictive value of 72.7% for distinguishing malignant from benign lung lesions. The overall accuracy of elastography strain ratio was 82.5%.ConclusionsEndobronchial ultrasound elastography can determine central lung lesions effectively. The diagnosis accuracy of SR in malignant lung lesions is higher than that of standard EBUS criteria and elastography grading score.