Cholelithiasis, sonographic Murphy sign, and GB wall thickening
• CT findings
Distended GB (measuring > 5 cm in short axis)
GB wall thickening (> 3 mm) with mural and mucosal hyperenhancement and pericholecystic fat stranding
Calcified gallstones may be visualized (15% of cases)
Hyperenhancement of adjacent liver parenchyma
• Hepatobiliary scintigraphy (Tc99-HIDA)
Nonvisualization of GB 4 hours after injection of radiotracer (or 30 minutes after administration of morphine)
• Complications
Gangrenous cholecystitis: GB wall necrosis with ↑ morbidity/mortality
Perforated cholecystitis: Most often occurs due to progressive GB distension with eventual rupture
Emphysematous cholecystitis: Secondary infection of GB with gas-forming organisms
Hemorrhagic cholecystitis: Hemorrhage within GB lumen or wall
TOP DIFFERENTIAL DIAGNOSES
• Acalculous cholecystitis
• Nonspecific GB wall thickening
• Peptic ulcer disease
• Acute pancreatitis
• Hepatic flexure diverticulitis
CLINICAL ISSUES
• Immediate cholecystectomy in patients who are good surgical candidates
• Percutaneous cholecystostomy with antibiotics in patients who are high-risk surgical candidates
(Left) Transverse US shows a large echogenic stone with an acoustic shadow and a thickened gallbladder (GB) wall. These findings, along with a positive sonographic Murphy sign, suggested acute cholecystitis, confirmed at surgery.
(Right) This hepatobiliary scan is of a 48-year-old woman with RUQ pain and surgically confirmed acute cholecystitis. Note the presence of bowel , absence of GB activity, and a subtle GB fossa rim sign . Persistent pericholecystic activity may be due to tissue edema and biliary stasis.
(Left) Axial CECT demonstrates a tiny stone within the gallbladder, with thickening of the GB wall, pericholecystic free fluid , and fat stranding , a constellation of findings diagnostic of acute cholecystitis.
(Right) Axial CECT of a 37-year-old woman shows GB wall thickening and GB fossa hyperenhancement . This surrounding hepatic parenchymal hyperemia is analogous to the rim sign of hepatobiliary scintigraphy.
TERMINOLOGY
Definitions
• Acute inflammation of gallbladder (GB) precipitated by an obstructing calculus within GB neck or cystic duct
IMAGING
General Features
• Best diagnostic clue
Cholelithiasis, with an impacted, immobile stone within GB neck or cystic duct
GB wall thickening
Positive sonographic Murphy sign: Pain with insonation directly over GB (accentuated during deep inspiration)
– May be absent in elderly, anesthetized, or diabetic patients, or those with GB necrosis
• Location
Stone impacted in GB neck or cystic duct
• Size
Distended GB (> 5 cm transverse diameter)
• Morphology
Distended GB more rounded than normal pear-shaped configuration
Fluoroscopic Findings
• ERCP
No filling of GB with contrast as result of cystic duct/GB neck obstruction by stone
May document common bile duct (CBD) stones in patients with associated choledocholithiasis
CT Findings
• Uncomplicated cholecystitis
Distended GB (measuring > 5 cm in short axis)
GB wall thickening (> 3 mm) with mural and mucosal hyperenhancement and pericholecystic fat stranding
Cholesterol/bilirubin stones typically not visible, but calcified gallstones may be visualized (15% of cases)
– Stone visualization may improve at higher kVp settings (140 kVp)
Hyperenhancement of liver parenchyma adjacent to inflamed GB (particularly in arterial phase)
• Complicated cholecystitis
Gangrenous cholecystitis:Focal interruption or lack of enhancement of GB wall due to necrosis
– Small ulcerations or outpouchings of GB wall may occur at these sites
– Intraluminal linear membranes (secondary to sloughed mucosa)
– Intramural or pericholecystic abscesses
Emphysematous cholecystitis: Gas in lumen/wall of GB
– CT is best modality to identify ectopic gas and make diagnosis of emphysematous cholecystitis
Hemorrhagic cholecystitis: High-attenuation intraluminal clot ± active extravasation of contrast
– Blood within GB lumen or bile ducts
Gallbladder perforation:Focal pericholecystic fluid collection or abscess adjacent to disrupted GB wall; extraluminal gallstones
– CT better than US for visualizing GB wall defect
MR Findings
• Distended GB with wall thickening, gallstones, and pericholecystic fat stranding/fluid
• Hyperenhancement of GB wall and mucosa on T1WI C+, with possible enhancement of surrounding liver parenchyma (rim sign)
• Use of hepatobiliary contrast agents (such as Eovist), which are normally secreted into bile, may be helpful
Lack of filling or delayed filling (> 60 minutes) of GB supports diagnosis of acute cholecystitis
Normal filling (< 60 minutes) does not exclude cholecystitis
GB usually fills with contrast in chronic cholecystitis
Ultrasonographic Findings
• Grayscale ultrasound
Uncomplicated cholecystitis
– Cholelithiasis (usually an immobile, impacted stone in GB neck or cystic duct), sonographic Murphy sign, and GB wall thickening > 3 mm
– GB distension > 5 cm in short axis
– Increased vascularity of GB wall on color Doppler images
Complicated cholecystitis
– Perforated cholecystitis: Pericholecystic abscess with collapsed GB
High-frequency transducer may allow better visualization of GB fundus to help exclude early perforation
Sonographic hole sign: Visualization of GB wall defect on US
– Gangrenous cholecystitis: Asymmetric wall thickening, intraluminal linear membranes, and irregularity and ulcerations of GB wall
Striated GB, contrary to prior teaching, not convincingly associated with gangrene
GB wall hyperemia may be absent on color Doppler images as result of wall necrosis
– Emphysematous cholecystitis: Gas in GB lumen and wall (brightly echogenic reflectors with dense “dirty” posterior acoustic shadowing)
GB itself may be difficult to visualize as result of shadowing from gas
– Hemorrhagic cholecystitis: Echogenic clot within GB lumen or visualized biliary tree
• Color Doppler
Increased vascularity of GB wall (flow may be absent in gangrenous cholecystitis)
Nuclear Medicine Findings
• Hepatobiliary scintigraphy
Tc-99m iminodiacetic acid derivatives
Nonvisualization of GB 4 hours after radiotracer injection (or 30 minutes after morphine administration)
Increased uptake in GB fossa (rim sign) due to hyperemia in 35% of patients
– Very specific (but not sensitive) for acute cholecystitis
– Positive predictive value of 57% for gangrenous cholecystitis
Hepatobiliary scintigraphy more sensitive (97%) and specific (90%) compared to US (88% and 80%, respectively)
False-positive results in patients who have recently eaten, undergone prolonged fasting (> 24 hours), received hyperalimentation, have severe concurrent illness, or who have severe hepatocellular dysfunction
Imaging Recommendations
• Best imaging tool
US is best screening tool
Hepatobiliary scintigraphy for confirmation (particularly when US is equivocal)
CECT to evaluate potential complications
• Protocol advice
Measure GB wall thickness adjacent to liver
Move patient during ultrasound to assess stone mobility
DIFFERENTIAL DIAGNOSIS
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with an acoustic shadow 
and a thickened gallbladder (GB) wall. These findings, along with a positive sonographic Murphy sign, suggested acute cholecystitis, confirmed at surgery.
, absence of GB activity, and a subtle GB fossa rim sign 
. Persistent pericholecystic activity may be due to tissue edema and biliary stasis.
within the gallbladder, with thickening of the GB wall, pericholecystic free fluid 
, and fat stranding 
, a constellation of findings diagnostic of acute cholecystitis.
. This surrounding hepatic parenchymal hyperemia is analogous to the rim sign of hepatobiliary scintigraphy.
GB wall thickening (> 3 mm) with mural and mucosal hyperenhancement and pericholecystic fat stranding
Uncomplicated cholecystitis
Complicated cholecystitis
Nonvisualization of GB 4 hours after radiotracer injection (or 30 minutes after morphine administration)
