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Radiology.Academy.Sk

Gallbladder

Adjacent to interlobar fissure, 4 x 10 cm, GB wall < 3mm, Phrygian cap (fundal fold), fast 4-8 hours before scan to ensure adequate GB distension




Gallstones


75% cholesterol, 25% pigment, symptomatic 1% per year, sensitivity 95%;

Mobile, echogenic, dependent or floating intraluminal structures that cast acoustic shadow, stones < 3 mm may not cast a shadow.


DDx: Polyp (non-mobile), Sludge ball (mobile w/o shadow)




GB completely filled w/ stones may resemble gas-filled loop of bowel - echogenic shadowing structure → differentiate by:

!! stones produce a clean shadow, while gas produces a dirty shadow




WES (Wall-Echo-Shadow) complex


3 arc shaped lines

Stone can float in very concentrated bile (cholesterol)


Sludge


Calcium bilirubinate granules and cholesterol crystals. Mobile, non-shadowing reflectors in the dependent portion of GB forms bile-sludge level or sludge balls, early stage of stones. May be a cause of pancreatitis.


Acute Cholecystitis


Positive Predictive Value of Gallstone and Positive sonographic Murphy’s sign is 92%; NPV is 95%



  1. Gallstones

  2. GB wall thickening > 3 mm

  3. Pericholecystic fluid

  4. Sonongraphic Murphy’s sign

  5. GB enlargement


5% acalculous cholecystitis (likely ischemic in very sick patients)


Emphysematous cholecystitis


Ischemic, older men, DM, infection w/ gas forming organisms, Perforation likely. Very bright reflections from gas in the wall of non-dependent portion of GB w/ dirty acoustic shadowing and ring-down artifact from gas


GB Carcinoma


Chronic irritation from stones. Most common sono appearance is soft tissue mass centered in GB fossa (w/ or w/o stone). Mmay also present as irregular, asymmetric, eccentric, focal or diffuse GB wall thickening, or polypoid mass


DDx: Tumefactive sludge, inflammatory GB wall thickening, Polyps, Mets (melanoma), Adenomyomatosis


Polyps


Cholesterol polyps: enlarged papillary fronds filled w/ lipid-laden macrophages, ball on the wall sign, < 5 mm, lack of shadow , non-mobile; lesions > 5 mm should be monitored, > 10 mm should be removed. Cholesterolosis: Strawberry GB


DDx: much less common are Adenomas, Papillomas, Leiomyomas, Lipomas, Neuromas; Mets (melanoma)


Adenomyomatosis


Mucosal hyperplasia and thickening of the muscular layer of the GB, mucosal herniation into the muscular layer - Rokitansky-Aschoff sinuses contain cholesterol crystals producing comet-tail artifacts along the near wall.


Biliary causes of GB wall thickening > 3 mm





Non-biliary causes of GB wall thickening > 3 mm





Porcelain GB


Calcified wall from chronic GB inflammation. Increased risk for GB carcinoma 20-60%. Prophylactic cholecystectomy. Echogenic arc w/ dense posterior shadowing. Search for malignancy.


DDx: entirely stone filled GB (WES complex), Emphysematous cholecystitis