Ultrasound Detection of Common Bile Duct Stones

Diagnostic Accuracy

Ultrasound demonstrates a sensitivity of 73% (44-90%) and specificity of 91% (84-95%) for detecting common bile duct stones, according to the American College of Radiology 1, 2
The positive post-test probability varies based on pre-test probability:
- Low pre-test probability (9.5%): 45% positive post-test probability 1
- Moderate pre-test probability (40.8%): 85% positive post-test probability 1
- High pre-test probability (65.8%): 94% positive post-test probability 1

Direct visualization of common bile duct stones on ultrasound is a very strong predictor of choledocholithiasis, as stated by the World Journal of Emergency Surgery 3, 4
A common bile duct diameter >10mm is associated with a 39% incidence of stones, while a diameter <9.9mm is associated with only 14% incidence of stones 4

MRCP demonstrates 93% sensitivity for detecting common bile duct stones, according to the American College of Radiology 1
EUS demonstrates 95-98.5% sensitivity for detecting common bile duct stones, as recommended by the American College of Radiology 1

The American College of Radiology recommends documenting specific findings in ultrasound reports, including direct visualization of stones if present 5
Relying solely on ultrasound common bile duct diameter measurements may lead to missed diagnoses, as diameter alone has limited predictive value, as stated by the World Journal of Emergency Surgery 3, 4