Figure 1.

Gangrenous cholecystitis. The gallbladder is markedly distended, with an antero-posterior diameter greater than 5 cm (calipers) (a). The gallbladder walls are thickened (up to 10 mm), with a layered appearance, showing multiple striations and alternating hypo/hyperechoic bands (calipers) (b,c). Inside the gallbladder lumen, a significant amount of biliary sludge (non-shadowing echoic material, determining a horizontal fluid–fluid level) surrounds a microlithiasis aggregate, a brighter echoic material with an acoustic posterior shadow (calipers) (d,e). A small triangular fluid collection is present between the gallbladder and liver surface (f).