New cholangiographic sign of common bile duct obstruction: initial opacification of intrahepatic ducts.

A previously undescribed sign of common bile duct obstruction during intravenous cholangiography - initial visualization of proximal intrahepatic ducts - was observed in 26 patients with surgically proven obstructive disease of the distal common duct. In all cases, opacification of intrahepatic biliary radicles occurred on standard interval films prior to visualization of the extrahepatic common bile duct, the reverse of the normal sequence. The abnormal opacification pattern reflects stasis of bile flow in the presence of distal obstruction and seems analogous to the urographic finding of opacified intra-renal calyces as the initial manifestation of distal ureteral obstruction. Recognition of the alteration in the initial cholangiographic opacification sequence signals the need for delayed films to confirm the diagnosis of a distal choledochal obstruction.