Diagnostic Radiology/Chest Imaging/Chest Signs

Be able to define, identify and state the significance of the following on a radiograph:


 * air bronchogram - indicates a parenchymal process, including non-obstructive atelectasis, as distinguished from pleural or mediastinal processes
 * air crescent sign - indicates a lung cavity, often due to fungal infection
 * deep sulcus sign on a supine radiograph - indicates pneumothorax
 * continuous diaphragm sign - indicates pneumomediastinum
 * ring around the artery sign (around pulmonary artery on lateral chest radiograph) - indicates pneumomediastinum
 * fallen lung sign - indicates a fractured bronchus
 * flat waist sign- indicates left lower lobe collapse
 * gloved finger sign - indicates bronchial impaction, which can be seen in allergic bronchopulmonary aspergillosis
 * Golden S sign - indicates lobar collapse with a central mass, suggesting an obstructing bronchogenic carcinoma in an adult
 * luftsichel sign - indicates upper lobe collapse, potentially due to an obstructing bronchogenic carcinoma in an adult
 * Hampton's hump - indicates a pulmonary infarct
 * silhouette sign - loss of the contour of the heart or diaphragm used to localize a parenchymal process (e.g. a process involving the medial segment of the right middle lobe obscures the right heart border; a lingula process obscures the left  heart border; a basilar segmental lower lobe process obscures the diaphragm)
 * cervicothoracic sign - a mediastinal opacity that projects above the clavicles is retrotracheal and posteriorly situated while an opacity effaced along its superior aspect and projecting at or below the clavicles is situated anteriorly
 * tapered margins sign - a lesion in the chest wall, mediastinum or pleura will have smooth tapered borders and obtuse angles with the chest wall or mediastinum while parenchymal lesions usually form acute angles
 * figure 3 sign - abnormal contour of the descending aorta, indicating coarctation of the aorta
 * fat pad sign or sandwich sign - indicates pericardial effusion on lateral chest radiograph
 * scimitar sign - an abnormal pulmonary vein in venolobar syndrome
 * double density sign - contour projecting over the right side of the heart, indicating enlargement of the left atrium
 * hilum overlay sign and hilum convergence sign -used to distinguish a hilar mass from a non-hilar mass

Be able to define, identify and state the significance of the following on a chest CT:
 * CT angiogram sign - enhancing pulmonary vessels against a background of low attenuation material in the lung
 * halo sign - suggesting invasive pulmonary aspergillosis in a leukemic patient
 * split pleura sign - a sign of empyema