In addition, intrahepatic calcified foci may also show acoustic shadowing, and a preliminary clinical judgment of the disease can be made based on the presence of acoustic shadowing. At present, it is believed that the reason for the formation of acoustic shadow is due to the high acoustic impedance when ultrasound encounters denser media such as stones, calcifications or bones, and the ultrasound waves are completely reflected back, and the deep layer presents an echo-free flat strip area because of the absence of acoustic energy. However, it is also clinically possible to have stony lesions without acoustic shadowing, which depends not only on the composition and structure of the stone itself, but also on the contrasting conditions of the media surrounding the stone, and is seen clinically mainly in viscous, deposited bile and in lesions with significant inflammation.