Diagnostic Ultrasound - Abdomen and Pelvis

Cholelithiasis
Diagnoses: Biliary System
IMAGING
• US: Highly reflective intraluminal structures
• Gravity dependent and mobile
• Collection of bright echoes with acoustic shadowing in
gallbladder (GB) representing GB packed with stones; may
be mistaken for duodenal bulb
• Nonshadowing gallstone when < 5 mm
• Radiography: Radiopaque in 10-20%
• T2WI MR: Small focus of signal void or low signal outlined
by markedly hyperintense bile within gallbladder
• Double-arc shadow sign or wall-echo-shadow (WES) sign: 2
echogenic curvilinear lines separated by sonolucent line
(anterior GB wall, bile, curvilinear echo from stone and then
shadow)
TOP DIFFERENTIAL DIAGNOSES
• Gallbladder polyp
• Gallbladder sludge
• Gallbladder carcinoma
KEY FACTS
• Focal adenomyomatosis
PATHOLOGY
• 80% cholesterol stones, containing > 50% cholesterol by
definition
• 20% pigmented stones, containing cholesterol and calcium
carbonate/bilirubinate
CLINICAL ISSUES
• Right upper quadrant pain/discomfort after fatty meal
• Asymptomatic, incidental finding on imaging
• Complications including acute or chronic cholecystitis,
choledocholithiasis, cholangitis, pancreatitis, gallstone ileus,
or cancer of gallbladder
DIAGNOSTIC CHECKLIST
• Ultrasound is best imaging tool for evaluation of patients
with upper abdominal pain/discomfort
• Nonshadowing calculi may be mistaken for other lesions in
GB such as polyp, sludge, carcinoma
(Left) Graphic shows multiple
small, faceted stones in the
gallbladder ſt and distal bile
duct . (Right) Left lateral
decubitus ultrasound in a
patient with acute calculous
cholecystitis shows an
impacted shadowing stone
in the gallbladder neck. Note
acoustic shadowing ſt. There
is mild gallbladder wall
thickening .
(Left) Left lateral decubitus
ultrasound shows a cluster of
large shadowing stones in
the gallbladder. Note the
acoustic shadowing ſt and
gallbladder wall thickening
. There was a positive
Murphy sign. (Right) Oblique
transabdominal ultrasound
shows multiple shadowing
stones in the gallbladder
fundus with a layer of
dependent sludge ſt.
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