Cholescintigraphy

Cholescintigraphy

99m Technetium-99m ( Tc)-labelled derivatives of iminodiacetic acid (hepatobiliary iminodiacetic acid [HIDA]; the utility of a hepatobiliary IDA or HIDA scan is that the radiotracer follows

Figure 71.8 Endoscopic ultrasonography. CBD, common bile duct; PD, pancreatic duct.

LIVER GALLBLADDER SMALL BOWEL the bilirubin metabolic pathway) are excreted into the bile. This allows visualisation of the biliary tree and gallbladder. In 90% of normal individuals the gallbladder is visualised within 30 minutes following injection, with 100% being seen within 1 hour ( Figure 71.9 ). The bowel is seen usually within an hour in the majority of patients. Non-visualisation of the gallbladder is suggestive of acute cholecystitis. If the patient has a contracted gallbladder, as often occurs in chronic cholecystitis, visualisation may be reduced or delayed. An abnor mally low gallbladder ejection fraction may be suggestive of gallbladder dyskinesia; however, interpretation of cholescintigraphy in this context is contro versial. Biliary scintigraphy may also be helpful in diagnosing bile leaks, biliary obstruction and in testing the patency of a bilioenteric anastomosis.

Figure 71.9 Dimethyl iminodiacetic acid (HIDA) scan before and after a meal to evaluate gallbladder function (courtesy of the Department of Nuclear Medicine, KEM Hospital, Mumbai, India).