The gallbladder is distended by heterogeneous content which may comprehend small echogenic stones and biliary sludge. Within the region of the gallbladder neck, there is an amorphous hypoechoic mass that does not show clear vascularity on colour Doppler. The gallbladder wall is thin and there are no pericholecystic fluid or stranding. The remainder of the liver and biliary tree is unremarkable (not shown).