gb pathologies

Cholelithiasis

Stones in GB due to bile imbalance; may be associated with sludge

Echogenic foci with posterior shadowing; mobile; WES sign if GB packed

Sludge

Bile stasis; precursor to stone formation; can mimic mass

Low-level echoes layering dependently; no shadowing mobile with position change

Homogeneous Sludge

Uniform low-level echoes

Smooth Echogenic dependent layer

Sludge balls

Round, mobile sludge aggregates

Round, mobile Echogenic foci; no shadowing

Tumefactive sludge

Mass-like sludge; mimics neoplasm

Non-mobile Echogenic mass; no shadowing

Gallstones VS sludge balls

Feature	Gallstones	Sludge Balls (Tumefactive Sludge)
Composition	Solid crystals (cholesterol, bilirubin, etc.)	Thickened bile and mucin
Appearance	Echogenic foci, well-defined, round/oval	Echogenic clumps, amorphous, may appear mass-like
Mobility	Highly mobile with position change	May move slowly or be semi-mobile
Shadowing	✅ Yes – posterior acoustic shadowing	❌ No shadowing
Twinkling artifact	✅ Often present on color Doppler	❌ Absent
Doppler flow	❌ No blood flow	❌ No blood flow
Common Pitfall	May be missed if very small	Can mimic gallbladder tumors

Mobile debris

Fine, swirling echoes in bile

Cloud-like, non-shadowing Echogenic material

Dependent sludge

Settles in most dependent GB region

Consistently layers in lowest portion

Sludge layering

Horizontal fluid-fluid level

Layered Echogenic line; shifts with patient position

Acute cholecystitis

Cystic duct obstruction → inflammation

Thick wall >3 mm, +Murphy’s sign, pericholecystic fluid, hyperemia, stones/sludge

Acalculous cholecystitis

Acute inflammation without stones; seen in critically ill, trauma, burns

Wall thickening >3.5mm

Enlarged GB, wall thickening, sludge, pericholecystic fluid, positive Murphy’s sign, no stones

Gangrenous cholecystitis

Necrosis of GB wall due to ischemia; complication of acute cholecystitis

Irregular wall thickening, intraluminal membranes, sloughed mucosa, absence of color flow, possibly gas

Emphysematous cholecystitis

Infection with gas-forming bacteria; elderly diabetics; surgical emergency

Gas in GB wall/lumen as echogenic foci with dirty shadowing or ring-down artifact; air-fluid levels

Gallbladder perforation

Wall rupture due to untreated acute cholecystitis

Wall defect, adjacent abscess/fluid, complex pericholecystic area, possible stones/debris outside GB

Chronic cholecystitis

Long-standing inflammation, fibrosis; often associated with stones

Thick fibrotic wall, contracted GB, stones, no hyperemia; WES sign

Types of cholecystitis

Type	Definition	Cause	Symptoms	Ultrasound Findings	Key Differentiator
Acute Cholecystitis	Sudden inflammation of GB	Cystic duct obstruction by gallstone (most common)	RUQ pain, fever, +Murphy’s sign, nausea	Thick GB wall (>3mm), distended GB, pericholecystic fluid, gallstones, +Sonographic Murphy’s sign	Gallstones with signs of acute inflammation
Acalculous Cholecystitis	Acute GB inflammation without stones	Critically ill patients (trauma, burns, sepsis, TPN)	Often vague or absent in non-verbal or ICU patients	GB wall thickening, distention, pericholecystic fluid, no stones	Critically ill + same findings as acute cholecystitis but no stones
Chronic Cholecystitis	Repeated or long-term inflammation	Recurrent gallstones or chronic irritation	Intermittent RUQ pain, intolerance to fatty meals	Thickened fibrotic GB wall, small/contracted GB, stones, WES sign	Shrunken GB with stones and no acute symptoms
Emphysematous Cholecystitis	Severe form with gas-forming bacteria	Clostridium, E. coli (diabetics at risk)	RUQ pain, fever, very ill, sepsis risk	Air in GB wall/lumen, ring-down artifact, dirty shadowing	Gas in wall or lumen; surgical emergency
Gangrenous Cholecystitis	Complication of untreated acute cholecystitis leading to necrosis	Prolonged inflammation & ischemia	Severe pain, fever, unstable vitals	Irregular GB wall, sloughed membranes, intraluminal debris, no Murphy’s sign	Necrosis with absent Murphy's sign, debris inside GB

Hydropic GB / Mucocele

GB distension from prolonged cystic duct obstruction; filled with mucus

GB >5 cm transverse, anechoic content, thin wall; often with obstructing stone in neck

Torsion of Gallbladder

GB twists on mesentery; elderly or congenital; surgical emergency

Enlarged, floating GB; whirlpool sign; hyperemic early, avascular later; abnormal orientation

Choledocholithiasis

Stones in CBD; may cause cholangitis or pancreatitis

Echogenic shadowing foci in CBD; dilated ducts; sludge or debris may be present

Cholangitis

Biliary duct infection, often due to obstruction

Duct wall thickening, dirty echoes in bile ducts, dilated intrahepatic ducts, possible abscess

Biliary atresia

Neonatal absence of biliary ducts; fatal if untreated

Absent GB; triangular cord sign; hepatomegaly; minimal/absent intrahepatic duct dilation

Choledochal cyst

Congenital cystic dilation of biliary ducts

Anechoic mass near porta hepatis; fusiform or saccular dilation of CBD

Gallbladder polyps

Benign mucosal projections ; usually <10mm

Non-mobile, non-shadowing Echogenic lesions

Types of gallbladder polyps

Type	Description	Common?	Malignant Risk?
Cholesterol polyps	Accumulation of cholesterol-laden macrophages	✅ Yes	❌ No
Adenomas	True epithelial tumors	⚠ Less common	⚠ Yes, potential for cancer
Inflammatory polyps	Related to chronic inflammation	🚫 Rare	❌ No
Adenomyomatosis	Thickening with intramural diverticula	Moderate	❌ No (usually)
Gallbladder carcinoma	Malignant mass/polyploid lesion	❗ Rare	✅ Yes

Benign vs malignant polyps

Feature	Benign	Suspicious for Malignancy
Size	<10 mm	>10 mm
Shape	Round, smooth	Irregular, sessile
Mobility	Fixed (unlike stones)	Fixed
Shadowing	No	No
Growth rate	Stable	Rapidly growing over time

Cholesterol polyps

Most common GB polyp type; lipid-laden macrophages

Small, multiple Echogenic polyps; non-shadowing, non-mobile; often <10mm

Gallbladder adenoma

Benign epithelial tumor; <1cm usually; pre malignant if >1cm

Non-mobile, non-shadowing Echogenic polyploid lesion; smooth contours; color Doppler may show flow

Gallbladder carcinoma

Rare, aggressive malignancy; associated with stones or porcelain GB

Irregular, heterogeneous mass; wall thickening; polypod lesion>1cm; may invade liver

Porcelain gallbladder

Calcified GB wall; strongly associated with carcinoma

Echogenic wall with shadowing; complete or partial calcification pattern

Courvoisier gallbladder

Enlarged painless GB due to distal biliary obstruction (usually pancreatic tumor)

Large distended GB; no stones; pancreatic head mass; dilated ducts

Biliary obstruction

Blockage in biliary outflow

Intrahepatic duct dilation; CBD>6mm; parallel channel sign; may see cause : stone, stricture, mass

Biliary stricture

Narrowing from surgery, trauma, or inflammation

Focal narrowing with proximal duct dilation; no vascular flow across narrowed segment

Cholesterolosis

“Strawberry GB”

Lipid deposition in mucosa

Echogenic foci in wall; diffuse or multiple small polyps; no shadowing; GB wall appears speckled

Adenomyomatosis

Hyperplasia of GB wall and mucosa with Rokitansky-Asschoff sinuses

Comet-tail artifacts; thickened wall; anechoic intramural spaces, especially in fundus

Rokitansky-Aschoff sinuses

Intramural mucosal diverticula seen in adenomyomatosis

Small anechoic intramural cystic spaces; ring-down or comet-tail artifacts

WES sign

Wall echo shadow : when GB is full of stones

Murphy’s sign

Clinical test used to diagnose conditions such as acute cholecystitis : inflammation of the GB

When pressure is applied to upper right abdomen while patient takes a deep breath = they experience pain and stops breathing due to discomfort

Comet-tail artifact

Reverberation seen in Adenomyomatosis

Triangular cord sign

Echogenic band at porta hepatic (biliary atresia)

Indicative of biliary atresia in infants, appearing as a triangular or tubular echogenic density near the portal vein bifurcation

Parallel channel sign

Dilated bile duct and portal vein side by side (biliary obstruction)

A sonographic finding observed during U/S of the biliary tree

Appears as 2 parallel lines representing dilated intrahepatic bile ducts alongside the adjacent portal vein branches

Sign is often associated with obstructive jaundice particularly when there is mild bile duct dilation

Whirlpool sign

Twisting of pedicle in GB torsion

The whirlpool sign of the mesentery, also known as the whirl sign, is seen when the bowel rotates around its mesentery leading to whirls of the mesenteric vessels

It represents the swirling appearance of the mesentery and superior mesenteric vein around the superior mesenteric artery

Ring-down artifact

Air/gas reverberation in emphysematous cholecystitis

Ring down artifact is a special type of resonance artifact

Appearance is similar to the ladder-like reverberation of comet-tail artifact but it is produced by a completely different mechanism

Biliary system

R&L hepatic ducts

Common hepatic duct

Common bile duct

Pear-shaped gallbladder

Cystic duct

Location of GB

Gall bladder fossa

Posteroinferior side of liver

Look for the Main Lobar Fissure(MLF) as a landmark

Anterior view of GB anatomy

Gallbladder anatomy

Pear shaped

Divided into : fundus, body, neck

Joins with the cystic duct

Gallbladder

Serves as a reservoir for bile

Sores and concentrates bile during the fasting state

Contracts upon eating

Location of bile ducts

Part of the portal triad, running with the portal veins and hepatic arteries, intrasegmentally 

Intrahepatic ducts are separated from extrahepatic ducts by the porta hepatis 

Intrahepatic ducts

Each hepatic ducts is formed by the unions of bile canaliculi from the liver lobules 

Intrasegmental ducts grow larger as they converge towards the porta hepatis 

Cystic duct

Contains the spiral valves of Hester

Small folds with the cystic duct that contain some muscle

Regulate the release of bile

CBD

Extrahepatic(outside liver) 

Created when the cystic duct(CD) and common hepatic duct (CHD) unite 

Length variation 

CD and CHD may join more distally 

= CBD will be shorter 

Common bile duct measurement

Normal common bile duct has a diameter of up to 6 mm 

Length variation 

- CD and CHD may join more distally 

- CBD will be shorter 

Vasculature - Gallbladder

Cystic artery originates from the right hepatic artery 

Venous drainage of the gallbladder is by the way of the hepatic portal system 

Normal gallbladder U/S

Main Lobar Fissure (MFL)

Intrahepatic ducts

NOT seen in normal patients

Small ducts that join together into larger ducts, ending in the left and right hepatic ducts

Common hepatic duct

Cystic duct

CHD vs CBD

Normal size biliary tree

CHD < 4mm 

CBD < 6mm 

Anatomic variations GB

Gallbladder may fold back on itself at the neck, forming Hartmann’s pouch 

Folding of the fundus = Phrygian cap

Partial septation 

Complete septation (double gallbladder) 

GB duplication 

Ectopic GB 

GB agenesis 

Mickey Mouse sign

Hartmann’s Pouch

Seen at the neck fo the gallbladder

Appear as a little pocket and can often catch gallstones within

Phrygian cap

Seen at a fold/kink in the fundus of the gallbladder

Common finding

Gallbladder folds

Folds are commonly seen and are normal

Gallbladder septations

Lumen of gallbladder fails at being completely open

Results in strands of tissue crossing through the lumen

Double gallbladder (GB duplication)

Full septations/2 gallbladders

Very rare

Can’t confirm by ultrasound

Ectopic gallbladder

Rare 

Can be located in a variety of anomalous positions : 

Intrahepatic 

GB completely surrounded by liver parenchyma 

May complicate the clinical diagnosis of acute cholecystitis because of a paucity of peritoneal signs resulting from the long distance between the GB and peritoneum 

Anomaly also makes cholecystectomy more difficult 

Suprahepatic 

Retrohepatic 

Supradiaphragmatic 

Retroperitoneal 

Gallbladder agenesis

Rare

Asymptomatic

Jaundice may be present with a dilated common bile duct

High incidence of choledocholithiasis

Intrinsic thickening of GB wall 

Cholecystitis 

Gallbladder perforation 

Sepsis 

Hyperplastic cholecystosis 

Gallbladder carcinoma 

AIDS cholangiography 

Sclerosing cholangitis 

Extrinsic thickening of gallbladder wall 

Hepatitis and cirrhosis 

Hypoalbuminemia 

Renal failure 

Right heart failure 

Ascites 

Multiple myeloma 

Portal node lymphatic obstruction 

Removal of the gallbladder - cholecystectomy 

Bile is no longer retained in the bile ducts; it is free to flow into the duodenum during fasting and digestive phases 

Extrahepatic bile ducts dilate, usually less than 1 cm 

Presbyductia

Dilation of CBD 

Increase of CBD size by 1mm per decade over 50 years old considered normal 

Also after a cholecystectomy 

Not considered dilated until greater 10 mm