目的　探讨超声对肺外周及胸膜≤ 2cm转移癌的诊断价值及声像图特征。方法　对中晚期肺、乳腺及消化系等恶性肿瘤患者行肋间及肋缘下肺底扫查 ,观察肺外周及胸膜下≤ 2cm小转移癌声像图特征及诊断率。结果　经确诊小转移癌 61例中 ,超声显示 5 6例 ( 91.8%) ,其中约半数病灶≤ 1cm。声像图表现多呈类圆形( 83 .9%) ,边界清晰规整 ( 73 .2 %) ,内部呈均匀的弱回声或无回声 ( 78.6%) ,局部胸膜不清晰或中断 ( 75 %) ,后方显示典型的长“彗星尾征”( 89.3 %)。根据以上特征 ,2 5例 ( 4 4.6%)在未知X线、CT、临床诊断结果情况下超声作出诊断 ,其中 6例为超声首诊。超声对检出的病灶定性诊断较X线、CT敏感 ,但易漏诊 ,肩胛骨、肋骨、肺气体等为主要影响因素。结论　对于肺周及胸膜下的转移癌 ,超声检查不受肺气体干扰 ,显示率较高 ,声像图典型 ,尤其后方长“彗星尾征”为敏感的超声指征。超声作为X线、CT的辅助诊断手段 ,有助于提高肺周转移癌的早期诊断率 Objective To investigate the diagnostic value and sonographic features of ultrasonography on peripheral lung cancer and pleural ≤ 2cm metastatic carcinoma. Methods In the middle and advanced stage of lung, breast and digestive system and other malignant tumors under the intercostal and costal bottom of the lung scan, observation of peripheral and subpleural ≤ 2cm small metastatic sonography features and diagnostic rate. Results Of the 61 patients diagnosed with small metastatic disease, 56 (91.8%) showed ultrasound, of which about half of the lesions ≤ 1 cm. The sonography showed mostly round (83.9%), clear and regular border (73.2%), internal uniform weak echo or echo (78.6%), local pleural unclear or interrupted (75%), The rear shows a typical long tail comet sign (89.3%). According to the above characteristics, 25 cases (4.6%) were diagnosed by ultrasound with unknown X-ray, CT and clinical diagnosis results. Among them, 6 cases were diagnosed by ultrasound. Ultrasound on the detection of lesions qualitative diagnosis of X-ray, CT-sensitive, but easy to missed diagnosis, scapula, ribs, lung gas as the main influencing factors. Conclusion For lung cancer and subpleural metastatic cancer, the ultrasonography is not disturbed by pulmonary gas, and the rate is high. The sonogram is typical, especially the posterior long tail comet sign is a sensitive ultrasound sign. As a supplementary diagnostic tool of X-ray and CT, ultrasound can help to improve the early diagnosis rate of lung metastasis