On ultrasonography the gallbladder is round and round-like in longitudinal and transverse views, with smooth hyperechoic gallbladder wall margins, the gallbladder cavity appears anechoic and the posterior aspect of the gallbladder is echogenically enhanced, with a long diameter of up to 8 cm, an anterior-posterior diameter of up to 3.5 cm and a wall thickness of up to 2 mm; a wall thickness of more than 3.0 mm is considered thickening of the gallbladder wall.