Complete lung ultrasound using liquid filling: a review of methods regarding sonographic findings and clinical relevance

(200w) Lung ultrasound (LUS) is widely used for the diagnosis of pulmonary diseases such as solid nodules and consolidations in contact with the pleural cavity. However, sonography for processes of central disease remains impaired due to total sound reflection at the air tissue interfaces in the ventilated lung. These acoustic barriers can be overcome by replacing intra-alveolar air with liquid. Such filling has been reported using perfluorocarbon, saline or emulsions out of those. In order to achieve acoustic access enabling the use of LUS, complete gas free content is required. Such lung tissue - liquid compound will have untypical physical properties that might impact upon the sonographic visualization of central structures. Up to now, the filling of the lung has been reported for very specific applications and not classified regarding their sonographic findings. This work was therefore motivated to review the literature for methods of lung liquid instillation, classifying their methodological strength and limitations for achieving acoustic access and sonographic findings. Finally, their use for ultrasound based clinical applications will be discussed and the need for research will be outlined.