Clinical Value of Ultrasound in the Diagnosis of Supraclavicular Lymph Node 
Metastasis of Primary Lung Cancer

Background and objective Primary lung cancer has been common malignant tumors. Accurate preoperative N staging can avoid unnecessary surgical operations, and patients with N3 has non-surgical treatment of indications. The aim of this study is to investigate the clinical value of ultrasound in the diagnosis of supraclavicular lymph node metastasis and staging of primary lung cancer. Methods We retrospectively analyzed 131 patients who were pathologically diagnosed with lung cancer from October 2012 to November 2013. All patients received ultrasound and contrast-enhanced computed tomograohy (CT) examination of the supraclavicular area, and those who were with positive results underwent ultrasound-guided biopsy. The accuracy of the two methods was compared according to their consistency with the pathological results. The pathological diagnosis was used as the diagnosis standard of lymph node metastasis. Results There were 50 cases of patients who were confirmed supraclavicular lymph node metastasis pathologically in a total of 131 cases of patients with lung cancer. Fifty-four cases were tested positive by ultrasound, and 50 cases were pathologically proven to be with lymph node metastasis. For comparison, the ratio was 36 out of 41 for contrast-enhanced CT. The sensitivity, specificity, You den's index, the positive predictive value and the negative predictive value of ultrasound (100%, 95.06%, 95.06%, 92.59%, 100%) was significantly higher than that of contrast-enhanced CT (72%, 93.83%, 65.83%, 87.80%, 84.44%). The differences of accuracy of the two methods in TNM staging of lung cancer had statistically significance (P