“…Transabdominal ultrasound is the gold-standard imaging for acute cholecystitis and detects over 80% of cases ( 31 – 35 ). In acute uncomplicated cholecystitis, ultrasound may show gallstones, a positive sonographic Murphy's sign, thickened gallbladder wall, pericholecystic fluid, “sludge” in the gallbladder, gallbladder distension, and hyperaemia of the gallbladder wall on Doppler ( 30 , 36 – 38 ). However, it is limited in detecting severe variants such as gangrenous or emphysematous cholecystitis or intra-abdominal abscess, where CT is more appropriate ( 14 , 24 , 30 , 37 ).…”