Transthoracic ultrasonography in respiratory medicine

Transthoracic ultrasonography (US) has become an essential modality for the evaluation of a wide range of thoracic pathologies by respiratory, emergency and critical care physicians. It can be performed with entry-level equipment and by personnel with minimal training. Its advantages include low cost, lack of radiation and immediate application at the point of care. The main indications for transthoracic US are the qualitative and quantitative assessment of pleural effusions, pleural thickening, diaphragmatic pathology, and chest wall and pleural tumours. US may also be used to visualise pulmonary pathologies that abutt the pleura, including consolidation and the interstitial syndrome. Transthoracic US is at least as sensitive as chest radiographs in the detection of pneumothoraces, and is useful in diagnosing skeletal abnormalities like rib fractures. It is the ideal tool to guide transthoracic procedures, including thoracocentesis and pleural biopsy. Moreover, US-assisted procedures can be performed by a single clinician with no sedation and minimal monitoring. US-assisted fine needle aspiration and/or cutting needle biopsy of extrathoracic lymph nodes, lesions arising from the chest wall, pleura, peripheral lung and mediastinum are safe and have a high yield in the of hands of clinicians. US can potentially also guide aspiration and biopsy of diffuse pulmonary infiltrates, consolidations and lung abscesses. Transthoracic US may also be used for the detection of pulmonary embolism.