Gallstone Ileus

• erosion of gallstone through GB wall into GI tract
• fistula between GB and duodenum (stomach, colon)
• large stones impact in ileum = mechanical SBO
• Bouveret’s Syndrome = gastric outlet obstruction due to impaction of a stone
• XR findings = Rigler’s triad
  • pneumobilia
  • dilated SB
  • ectopic calcified gallstone

Acalculous Cholecystitis CT criteria

2 major or 1 major + 2 minor

Major criteria:

• Gallbladder wall thickening greater than 3 mm
• Subserosal halo (ie, gallbladder wall edema)
• Pericholecystic fatty inflammation
• Pericholecystic fluid (without ascites or hypoalbuminemia)
• Mucosal sloughing
• Intramural gas

Minor criteria:

• Gallbladder distention (>5 cm transverse)
• High-attenuation bile (sludge)

Porcelain Gallbladder

• calcification of gallbladder wall
• associated with chronic inflammation, 95% have gallstones
• up to 61% risk of malignancy, needs prophylactic cholecystectomy

Adenomyomatosis of gallbladder

• mucosal hyperplasia and thickening of muscular layer
• Rokitansky-Aschoff sinuses = mucosal herniation through muscle layer, contain cholesterol crystals
• U/S: bright reflections with comet-tail artifacts

Gallbladder polyps

• less than 5mm or 5-10mm in size, nonmobile, no shadow
• most common polyp is a cholesterol polyp
• others: adenomas, papillomas, leiomyomas, lipomas, neuromas
• metastatic melanoma produces gallbladder polyps
• 5-10mm polyps require folllow up.

Gallbladder Wall Thickening

• Cholecystitis: acute, chronic, acalculus, xanthogranulomatous
• Gallbladder carcinoma
• Adenomyomatosis
• Liver cirrhosis
• Hepatitis
• Right CHF
• Renal failure
• Pancreatitis

Gallbladder Carcinoma

• 5th most common GI malignancy
• stones are a risk factor
  • 75% have stones
  • chronic inflammation leads to epithelial dysplasia –> adenocarcinoma
• 20% 5ys
• 80% have direct tumor invasion at presentation
• ST mass in GB lumen, partially or completely obliterates GB lumen
• Greater than 1 cm (distinguish from polyp)
• irregular, asymmetric and eccentric wall thickening
• polypoid intraluminal mass
• porcelain gallbladder
• early spread to liver and lymph nodes
• invades liver, bile ducts, portal veins
• invades hepatoduodenal ligament –> CBD obstruction

Gallbladder Masses

Common

• polyps
• adenomyomatosis
• gallbladder cancer
• tumefactive sludge

Uncommon

• Metastasis
• Chronic cholecystitis

Cholecystitis

• obstruction of biliary outflow from bladder (ie. stone)
• U/S 95% sensitivity, 100% PPV and NPV for detecting stones
• 5% without stone; acalculous cholecystitis
• emphysematous cholecystitis
  • occurs in elderly men, diabetics
  • gas-forming organisms; e coli, clostridium
  • 5 times more likely to perforate
  • air reflections on US
  • percutaneous cholecystostomy as temporizing measure

Findings

• gallstones (shadowing and mobile)
• gallbladder wall thickening (greater than 3 mm)
• gallbladder enlargement (greater than 4 x 10 cm)
• pericholecystic fluid
• stone impacted in gallbladder neck or cystic duct
• Murphy’s sign
• PPV of stone + Murphy’s sign = 92%
• bright reflection in non-dependent gall bladder wall = emphysematous cholecystitis

Differential

• polyp (nonmobile)
• sludge (no shadowing)