“…Among five urgent US targets (FAST, pleura, bladder, abdominal aorta, and gallbladder), gallbladder US is the most difficult to perform [14]. Previous studies have shown that emergency department bedside ultrasonography (EUS) performed by EPs had a good agreement with the radiologists in detecting cholelithiasis; however, the EPs in these studies had varying degrees of experience [15,16].…”