1 Diagnostic and Interventional Ultrasound Unit, Valle del Serchio General Hospital, Lucca, Italy.
2 Pulmonary Medicine Unit, Department of Medical and Surgical Sciences, Fondazione Policlinico Universitario Agostino Gemelli, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy.
3 Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario Agostino Gemelli, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy.
4 Emergency Department, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico San Matteo, and Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy.