Introduction: Chest sonography was used until recently mainly for diagnosis of pleural diseases. High resolution ultrasound machines enable ultrasound application not only in pleural diseases detection, but in diagnosing peripheral lung and mediastinal lesions. Ultrasonography can define the origin and structure of the lesion of thoracic wall, pleural and peripheral lung lesions and mediastinal lesions.
Pleural lesions: Ultrasonography is very useful in diagnosing pleural effusion and distinguishing pleural fluid and pleural thickening. This method can also differentiate transudate from exudates and tumor mass from pleural thickening.
Lung lesions: Ultrasonography can reveal the cause of white hemithorax differentiating pleural effusion from large tumor mass or atelectasis. Peripheral pulmonary lesions, extending into visceral pleura can be visualized by ultrasonography and differentiation solid tumor from inflammation is possible.
Mediastinal lesions: Computerized tomography and magnetic resonance are methods of choice in diagnosing mediastinal diseases. Ultrasonography is useful in distinguishing normal thymus from tumor mass and for ultrasonography-guided biopsy.
Conclusion: Ultrasonography is a very useful second line method in diagnosis of chest disease. The advantages of this method include bed, side availability, absence of radiation, and guided aspiration of fluid-filled areas and solid tumors.