RADIOLOGY: HEPATOBILIARY: Case# 85: ACUTE CHOLECYSTITIS. Ninety-three year old black female with history of diverticulosis who presents complaining of right-sided abdominal pain, nausea and vomiting, and increased fever x2 days. The patient has a past surgical history of a total abdominal hysterectomy for fibroids and an appendectomy. An ultrasound yesterday shows gallstones and positive sonographic Murphys sign. Rule out diverticulitis versus an abscess. The gallbladder wall is thickened with inflammatory changes surrounding the gallbladder and fluid seen extending into the right paracolic gutter. There is a simile hepatic cyst within the posterior segment of the right lobe. There is no intra- or extrahepatic biliary ductal dilatation seen. There is thickening of the sigmoid colon with numerous diverticula, but there is no evidence of diverticulitis. The uterus and appendix are surgically absent. The right adrenal gland is slightly enlarged. Otherwise, the kidneys, left adrenal gland, pancreas, lung bases and urinary bladder are unremarkable. Acute cholecystitis, or inflammation of the gallbladder, can be classified as calculous (associated with gallstones) or acalculous. Symptoms associated with the onset of acute cholecystitis include progressive right upper quadrant or epigastric pain, mild fever, anorexia, tachycardia, diaphoresis, and nausea and vomiting. Lab abnormalities associated with this condition include mild to moderate leukocytosis often accompanied by mild elevations in serum alkaline phosphatase values. Most cases of acute cholecystitis are diagnosed clinically, via ultrasound, or via radionuclide hepatobiliary scan. CT is used to evaluate complicated or atypical cases. CT findings include gallstones (in 95% of patients), distended gallbladder lumen (greater than 5cm), thickening of the gallbladder wall (greater than 3mm), halo of subserosal edema in the gallbladder wall, pericholecystic fluid collection associated with perforation, increase in bile density to ~20 HU (due to biliary stasis, intraluminal pus, hemorrhage or cellular debris), and air in the gallbladder wall (emphysematous cholcystitis).