Why would a hidascan show no tracer in bowel after 90 minutes but yet mrcp is normal (except little sludge in gbneck)?the intra&extra hepatic biliary are non-dialated.hs shows hepatic tracer with excretion into biliary system and gb seen in 16 mins?

After the tracer is injected in the vein, it goes to the liver, gets excreted in the bile, goes throughcthe biliary ducts and accumulates in the gallbladder which is a reservoir. From the gallbladder it is released into the small bowel. If after a certain time no tracer is seen out of the gallbladder it means the cystic duct is obstructed ( by stone, sludge etc.)