Dilation of the common bile duct typically means a 'widening' of the duct at some point. It expands in size due to possible blockage by a stone, widens due to a spasm downstream that results in a back-up of bile and pancreatic fluids, or it may expand due to another form of disease state. Some people experience a dilation/wideing of the CBD in the years following removal of the gallbladder although the reason this happens is unknown at the current time.
what is the mean of common bile duct dilation (9mm)?cdc