Interest in transthoracic ultrasound (US) procedures increased after the availability of portable US equipment suitable for use at the patient's bedside. It is possible to detect space-occupying lesions of the pleura, pleural effusion, focal or diffuse pleural thickening and subpleural lesions of the lung, even in emergency settings. Transthoracic US is useful as a guidance system for thoracentesis and peripheral lesion biopsy, where it minimises the occurrence of pneumothorax and haemorrhage. Transthoracic US imaging is strongly influenced by physical interaction of the ultrasonic beam at the tissue/air interface, which gives rise to reverberations classified as simple (A-line), "comet tail" and "ring down"(B-line) artifacts. Although these artifacts can be suggestive of a disease condition, they are essentially imaging errors present even in normal subjects and in empty-pleura post-pneumonectomy patients. In order to clarify some confusion and to report on the state of the art, we present a review of the literature on transthoracic US in diseases of the pleura and peripheral lung regions and our own clinical experience over 3 decades. The review focuses on quality assurance procedures and their value in diagnostic imaging and patient monitoring and warns against possible inappropriate indications and misleading information. Thoracic US is much more than "fishing for the moon in the well".

TUS is easily reproducible and we proved it to be a useful complementary diagnostic tool for the diagnosis and the follow-up of CAP.

Although numerous studies have been conducted on the use of ultrasonography (US) for the examination of thoracic structures, this procedure is not as widely accepted as abdominal US. The newer portable scanners can be used at the bedside to detect pleural malignancies and effusions, as well as peripheral lung nodules of the lung, even in seriously ill patients. Focal thickening of the pleura can be easily detected with US and further investigated with a US-guided biopsy. US guidance can also be used during percutaneous drainage of pleural effusion or transthoracic biopsy of peripheral lung lesions, thus reducing the incidence of procedure-related pneumothorax to almost zero. We review the current literature on thoracic US and present our clinical experience with the technique in large groups of patients with pleural and peripheral lung diseases.Sommario L'ecografia del torace non è ancora diffusa quanto quella addominale, nonostante una notevole quantità di studi ne attesti l'importanza. Le apparecchiature più recenti permettono di diagnosticare neoplasie, versamenti pleurici e noduli polmonari periferici al letto del paziente, anche nei casi più gravi. L'ispessimento pleurico focale è facilmente messo in luce dall'ecografia e può essere ulteriormente studiato tramite la biopsia ecoguidata. Questa può essere praticata anche su lesioni polmonari periferiche, riducendo quasi a zero il rischio di pneumotorace. In questo articolo esaminiamo la letteratura recente sull'ecografia del torace e presentiamo la nostra esperienza clinica su numerosi pazienti con patologia pleurica e della periferia polmonare. ª