Thoracic ultrasonography is an important imaging adjunct for diagnosing and managing disease involving pediatric chest following careful evaluation of chest radiographs. Ultrasound was initially applied mainly to detect pleural fluid however, the applications of US for the chest have been widely extended over time. Although air in healthy lungs and calcium in bony structures hinder transmission of the US beam, chest lesions involving the lung, mediastinum and pleura can be studied through anatomical “acoustic windows”. The technique has several advantages that are particularly beneficial in children: unlike CT, US does not use ionizing radiation or require administration of contrast material to identify vascular structures, most patients do not require sedation and examination can be performed at bedside. Improvements in the resolution of the equipment provide images of excellent quality, which facilitates recognition of parenchymal, pleural and extra-pleural lesions. Ultrasound also excels at demonstrating and characterizing pleural fluid collections. Sonography is the only technique that permits visualization of the lesions in real time and in different planes.
In this review, I will discuss and illustrate the US findings of diseases affecting lung parenchyma, pleura, diaphragm and mediastinum.