How is use of abdominal US in acute abdomen?

● For acute cholecystitis: shows us liver, spleen and kidneys. ● Appearance in ultrasound: thickening of the wall of gallbladder >1cm ingeneral or we see periparietal edema (behind the gallbladder between it and the liver). If there is air in the biliary tract: fistula with intestine. If still nothing shows: go for CT