The causes of gallbladder shrinkage in ultrasound are mainly seen in the following four aspects, including gallbladder atrophy, congenital abnormalities, feeding factors, and examination errors, etc., as follows: First, gallbladder atrophy: gallbladder atrophy is mainly seen in recurrent gallbladder inflammation with gallbladder stones, when there is not only gallbladder shrinkage, but also significant thickening of the gallbladder wall, and there will be multiple strong echogenicity, which can move with body position. For the gallbladder shrinkage caused by this condition, the atrophied gallbladder should be removed in time, otherwise it may lead to gallbladder cancer in a long time. Second, congenital abnormality: the gallbladder is congenitally abnormal in development and is relatively small in itself, at this time the function of the gallbladder is normal, the function of the liver is also normal, and the patient does not have clinical symptoms, so regular follow-up observation is possible at this time. Third, eating factor: the gallbladder shrinkage is the result of ultrasound performed after eating, when the gallbladder will contract and discharge bile, which is the normal performance of the gallbladder after meals, and the gallbladder can be measured under fasting to clarify whether there is shrinkage. Fourthly, examination error: Ultrasound examination error is caused by the fact that there is no gallbladder shrinkage, but is caused by abnormal ultrasound examination, then you can further perform gallbladder MRI to clarify whether there is gallbladder shrinkage.