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)
Findings
Evaluate gallbladder for:
- GB wall measurement
- Pericholecystic free fluid
- Gallstones
- Common Bile Duct (CBD) measurement
- Sonographic Murphy's (pain with ultrasound probe palpation over gallbladder)
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
- identify by hypoechoic "shadowing" behind hyperechoic stones
- 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 to views
- Ascitic fluid: located throughout peritoneum, including Morrison’s pouch. Pericholecystic fluid is localized to the anterior side of the gallbladder
See Also
Source
Sonoguide