Thoracic sonography.

Sonography has inherent limitations for thoracic imaging because sound waves are reflected by bone and air space (such as in lung parenchyma). However, sonography is less expensive and more convenient than computed tomography (CT) or magnetic resonance imaging (MRI); it provides immediate information with real-time imaging; and it can provide information not available from a standard radiograph. This review describes the utility and limitations of sonography and compares sonography to radiography, CT, and MRI with regard to diagnosing pleural, pulmonary, and aortic diseases, including pneumothorax, pleural effusions and masses, hemothorax, empyema, consolidated lung, pneumonia, pulmonary abscess, pulmonary embolism, mediastinal masses, aortic dissection, aortic intramural hematoma, and penetrating aortic ulcers.