PLEURAL EFFUSION DIAGNOSIS Chest radiography is often the first imaging method used to detect an effusion.The volume of fluid in the pleural space needs to exceed 250 mL to be visualized on the chest radiograph.When an effusion is present,there is blunting of the costophrenic angle(肋膈角)on the posteroanterior chest radiograph,and a meniscus(新月液面) can be seen posteriorly on the lateral chest radiograph. Fluid may also collect in either the minor or major fissures.第 一 部 分 DIAGNOSIS Chest radiography is often the first imaging method used to detect an effusion. The volume of fluid in the pleural space needs to exceed 250 mL to be visualized on the chest radiograph. When an effusion is present, there is blunting of the costophrenic angle（肋膈角） on the posteroanterior chest radiograph, and a meniscus（新月液面） can be seen posteriorly on the lateral chest radiograph. Fluid may also collect in either the minor or major fissures. PLEURAL EFFUSION