Definition: Acute inflammatory disease caused by poor bile drainage stagnation due to bacteria, stones, parasites, etc., obstructing the bile duct, or pancreatic reflux. Pathology: Simple, septic and gangrenous. At the beginning of the disease, the gallbladder is congested, edematous, and infiltrated with white blood cells. Further development, the cyst is filled with turbid bilious pus, mucosal necrosis, ulcer formation, and there may be a large number of leukocyte infiltrates in all layers of the cyst wall or small abscesses, which may lead to hemorrhagic infarction of the gallbladder wall, forming acute gangrenous cholecystitis. Clinical manifestations: Sudden onset, severe pain in the right upper abdomen, when the inflammation spreads to the peritoneum, it can cause abdominal muscle tonicity and traction pain to the right scapular region. Patients often have fever, stomach chills, vomiting and other symptoms. An enlarged gallbladder can be palpated in the right upper abdomen, and there is obvious pressure pain. Ultrasound manifestations: 1. Gallbladder wall thickening is normally 1-2mm, and greater than or equal to 3mm is considered thickening. In acute cholecystitis, the gallbladder wall is 45%-100% thickened, mostly up to 0.5-1.0 cm, with limitation or involvement of the whole gallbladder wall. 2. The “bilateral shadow” sign in the gallbladder wall is caused by subplasma edema, hemorrhage and inflammatory cell infiltration. 3.The enlarged gallbladder fluid is caused by the obstruction of the cystic duct or common bile duct due to cholecystitis combined with stones and poor bile excretion. 4, ultrasound Murphy’s sign positive probe placed on the surface of the gallbladder body, slightly forceful pressure, the patient deep inspiration, there is pain, suggesting positive 5, gallbladder perforation perforation, dilated gallbladder shrinkage, luminal echogenicity increased, irregular morphology, the gallbladder around the boundary of the dark area can be seen, the thickness of the point or band echo; if there is an abscess around, showing round or oval transmissive dark area or edge If there is an abscess around it, it shows round or oval dark areas or irregularly edged hypoacoustic masses. 6, Rarely, gallbladder emphysema, gas accumulation in the cavity of the gallbladder, manifested as a dense strong light mass, or a “comet tail-like” reflection. If the fasting gallbladder is smaller than normal size, it indicates severe lesion and loss of function; if the gallbladder is enlarged, it means there is obstruction below the gallbladder.