Amorphous, mid-/high-level echoes within gallbladder or bile ducts

Free floating or mass-like, mobile, settling in dependent position

Floating punctate echoes may show ring-down artifact

Occasionally round, low to intermediate echogenicity and mass-like: “Tumefactive” sludge

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  No posterior acoustic shadowing (unlike stones) and no internal color flow (suggesting mass)

Cholelithiasis

Focal adenomyomatosis

Gallbladder polyp/mass

Gallbladder pus or blood

Presence of particulate material in bile

Larger particles (1-3 mm) are microliths, which may become nidus for gallstones

Predisposing factors: Prolonged fasting/total parenteral nutrition, pregnancy, rapid weight loss/bariatric surgery, critical illness

Mostly asymptomatic

May have clinical symptoms when complications occur

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  Stone formation, biliary colic, acute cholecystitis or pancreatitis

Adjust focal zone to gallbladder for optimal resolution

Distinguish sludge from side lobe artifacts

Change patient position to demonstrate mobility

Use color Doppler, but be aware that twinkling artifact may be mistaken for color flow