Point-of-care ultrasound in the acute abdomen and gastrointestinal emergencies: An evidence-based guide and the case for standardisation

Figure 4 Annotated sonographic criteria on representative point-of-care ultrasound images acquired by the authors. A: Small-bowel obstruction – a fluid-filled dilated loop with valvulae conniventes (the keyboard sign), with a second dilated loop also labelled; B: Acute cholecystitis – an intraluminal gallstone with posterior acoustic shadowing, adjacent to the anechoic gallbladder lumen; C: Acute cholecystitis – the gallbladder wall, the anechoic lumen and a gallstone. Arrows indicate the labelled structures. Diagnostic thresholds (dilated small-bowel loop > 2.5 cm conventionally, with 2.75 cm proposed as a bedside-specific candidate; gallbladder wall > 3 mm in the emergency literature and ≥ 4 mm in the Tokyo Guidelines 2018) are defined, referenced and compared in the main text. GB: Gallbladder.