Gallstone – ultrasound
Gallstone. This patient has a large solitary calculus in the gallbladder. The bile in the gallbladder is described as being ‘anechoic’, while the calculus is ‘echogenic’. Because the calculus reflects so many of the ultrasound waves back to the probe, we cannot see beyond it – the dark area deep to the calculus (arrows) is called ‘acoustic shadowing’.