Table I.

Ultrasonography and ERCP features

Features	A1/A2 P-value	B1/B2 P-value	A1/B1 P-value	A2/B2 P-value
Stones in gallbladder	NS	NS	NS	NS
Stones single vs. multiple	NS	NS	< 0.05	< 0.05
Stones in biliary tract	NS	NS	< 0.05	< 0.05
Cholestasis	NS	NS	< 0.05	< 0.05
Common bile duct > 6 mm	NS	NS	NS	NS
Cholecystitis	NS	NS	NS	< 0.05
Biliary prothesis	NS	NS	NS	NS