1 Unit of Interventional and Diagnostic Ultrasound of Internal Medicine, IRCCS "Casa Sollievo della Sofferenza", Viale Cappuccini, 71013 San Giovanni Rotondo, Italy. Electronic address: sperandeom@libero.it.
2 Unit of Internal Medicine, IRCCS "Casa Sollievo della Sofferenza", San Giovanni Rotondo, Italy.