Biliary ultrasound

Technique

• Can use phased array or curvilinear probe
• Look in midclavicular line at Right 11th/12th intercostal spaces or scan anteriorly from Morrison's pouch
• Patient in Left lateral decubitus (if can tolerate)
  • Allow for better visualization of gallbladder (moves gallbladder anteriorly)
  • Better visualization of gallstones

Landmarks

• Liver - used as a viewing window
• Exclamation Point Sign: portal vein and medial longitudinal fasciculus (MLF)

Anatomy & Pathophysiology

• Gallstones are classified as cholesterol stones and pigmented stones (black and brown), and are present in approx 20% of females and 8% of males in the United States
• These stones cause the majority of all biliary tract problems, and depending on where the stone become impacted, specific problems occur.
• Bile flows out the gallbladder, down the cystic duct into the common bile duct, and ultimately into the 1st portion of the duodenum.

Findings

Evaluate gallbladder for:

1. GB wall measurement
2. Pericholecystic free fluid
3. Gallstones
4. Common Bile Duct (CBD) measurement
5. Sonographic Murphy's (pain with ultrasound probe palpation over gallbladder)

• 

  Gallbladder wall thickening.

• 

  Acute cholecystitis.

• 

  Actue cholecystitis: Gallstone impacted in the neck of the gallbladder with gall bladder wall thickening.

Measurements

• GB wall is <4 mm + 1 mm/decade
  • Measure the anterior wall at narrowest point with a short-axis view
  • Causes:
    • 1. Acute cholecystitis
    • 2. Ascites
    • 3. CHF

• Gallstones
  • identify by hypoechoic "shadowing" behind hyperechoic stones
    • if no shadowing, may be polyps, sludge, etc.
  • SIN Sign: Stone-in Neck

• Common Bile Duct
  • Measure from inner to inner
  • Normal is up to 4 mm to age 40 (add 1mm per decade thereafter)
  • Mickey Mouse Sign: Portal Vein (face), CBD (right ear), and hepatic artery (left ear)
    • Color doppler will demonstrate the vein and artery

• Acalculous cholecystitis
  • GB is >10cm long & >4 cm wide

Pitfalls

• Easily confused with duodenum: look for peristalsis
• Contracted GB: three distinct wall layers is no pathological
• GB Polyp: soft tissue masses attached to the wall of the gallbladder and differentiated from gallstones by their lack of mobility and shadowing
• Renal Cyst: cysts in the superior pole of the kidney; get two views
• Ascitic fluid: located throughout peritoneum, including Morrison’s pouch. Pericholecystic fluid is localized to the anterior side of the gallbladder

See Also

• Ultrasound (Main)
• Gallbladder Disease (Main)
• WES sign

Source

Sonoguide