Gallbladder sludge

Gallbladder sludge, also known as biliary sand, biliary sediment, or thick bile, is a mixture of particulate matter and bile, normally seen as a liquid-liquid level in the gallbladder on ultrasound, corresponding to the precipitate of bile solutes. 


These precipitates consist of cholesterol monohydrate crystals, calcium bilirubinate granules, calcium salts, and mucus secreted by the gallbladder 1

Radiographic features


Gallbladder sludge appears as a low amplitude homogeneous echoes, layering on the posterior wall, and frequently forming fluid-fluid level with anechoic bile above it. 

  • it moves slowly with changes in patient position
  • sludge does not cause shadowing unless associated with gallstones 2

Sludge can get compacted forming a mass-like lesion referred to as tumefactive sludge 4

  • hypoechogenic well defined intraluminal mass
  • no posterior acoustic shadowing
  • no internal vascularity at color Doppler
  • mobility is not always demonstrated, therefore, raising differentials with polyps or gallbladder carcinoma 
  • T1: high-signal
  • T2: iso- to mild hyperintensity 
  • T1 C+ (Gd): no enhancement
  • DWI/ADC: no diffusion restriction
Gallbladder and biliary tract pathology
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Article information

rID: 21620
Section: Gamuts
Synonyms or Alternate Spellings:
  • Biliary sand
  • Biliary sediment
  • Sludge in gallbladder
  • Tumefactive gallbladder sludge
  • Tumefactive sludge

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Cases and figures

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  • Case 4
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