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Hepatobiliary scintigraphy performed in a patient suspected of having common bile duct obstruction showed persistence of the hepatic parenchymal phase and no bile duct or gallbladder activity during the first hour of imaging. On endoscopic retrograde cholangiopancreatography examination several hours later, an obstructing gallstone was identified in the common bile duct, and the stone was extracted in conjunction with a papillotomy. Delayed scintigraphic images at 6 hours were unchanged from the earlier views, but imaging at 24 hours showed tracer activity in the small bowel and colon along with persistent hepatic parenchymal activity. These results demonstrate that hepatobiliary radiopharmaceuticals remain in an excretable form in the liver in patients with complete common duct obstruction, but that resumption of bile flow and tracer excretion does not occur until a number of hours after relief of the obstruction.

Visualization of a "dilated cystic duct" during standard hepatobiliary imaging represents a potential source of false-negative cholescintigraphy. Intravenous morphine, commonly used to shorten study time and improve the specificity of hepatobiliary imaging, may, by virtue of its pharmacologic/physiologic actions, accentuate the appearance of a "dilated cystic duct." We present a case of transient cystic duct visualization following morphine administration in a patient with an obstructing cystic duct calculus.

Previous results from tests on a limited number of patients suggested that the combination of relatively normal hepatocyte clearance, prolonged parenchymal transit time, and eventual passage of radiotracer into the intestine or gallbladder without evidence of biliary tract dilatation were relatively specific for intrahepatic cholestasis. We reevaluated the specificity of cholescintigraphy for the diagnosis of intrahepatic cholestasis in an unselected group of patients from a general hospital. Sixteen patients had the cholescintigraphic findings of intrahepatic cholestasis and an established diagnosis of biliary tract dilatation or nondilatation by ultrasound, ERCP, or intraoperative cholangiography. Using 6 mm as the upper limits of normal for the diameter of the common hepatic duct by ultrasonography resulted in a specificity of 63% (10 correct out of 16); using 6 mm plus 1 mm for for every decade over 60 years of age gave a specificity of 75% (12 correct out of 16); and using the more liberal criterion of 8 mm as the upper limits of normal increased the specificity to 81% (13 out of 16). The data suggest that cholescintigraphy alone is unreliable in differentiating intrahepatic cholestasis from extrahepatic obstruction, even when the obstruction is partial and radiotracer eventually passes through the extrahepatic biliary tract.

Extracorporeal shock wave lithotripsy (ESWL) has been reported to be a safe and relatively effective non-invasive treatment for radiolucent gallbladder calculi in selected patients. Ideally, the goal of successful treatment is the passage of all fragments from the gallbladder into the intestinal tract. Biliary colic has been reported in up to 35% of treated patients, although complications such as cholecystitis, cholangitis, common bile duct obstruction, and pancreatitis are surprisingly infrequent. Cholescintigraphy is the procedure of choice in patients with biliary colic and suspected acute cholecystitis. It has proven to be more sensitive than ultrasound in detecting acute common bile duct (CBD) obstruction, since functional obstruction precedes morphologic dilatation of the CBD. This report reviews two cases of post-lithotripsy cystic and common duct obstruction and discusses the role of Tc-DISIDA scintigraphy following gallstone ESWL.

Hepatobiliary imaging with Tc-99m IDA derivatives has proven value for evaluation of biliary disease. Prompt hepatocellular uptake with persistent nonvisualization of the common bile duct and bowel is usually indicative of a high-grade common bile duct obstruction, but is not pathognomonic. A functional abnormality due to hepatocyte dysfunction resulting in intrahepatic cholestasis can also cause this pattern. Two cases of hepatocellular excretory dysfunction, one due to E. coli endotoxemia with intrahepatic cholestasis and the other due to acute hepatitis A that produces ductal obstructive patterns on Tc-99m disofenin scintigraphy in patients with documented patent biliary ducts, are reported. Transhepatic cholangiography or endoscopic retrograde cholangiography may be useful when the diagnosis of biliary ductal obstruction is in doubt.

The records of all patients undergoing hepatobiliary imaging at our hospital from January 1980 to March 1983 were reviewed and 29 scans met the criteria for a pattern consistent with complete biliary tract obstruction. Biliary tract obstruction (due to choledocholithiasis, primary or secondary carcinoma involving the common bile duct, and pancreatitis) was documented in 24 of these patients. However, the remaining five patients had a patent common bile duct, and the etiologic factor was intrahepatic cholestasis secondary to sepsis in four and peritonitis in one. A classification of altered biliary dynamics in hepatobiliary imaging, which is based on the classification of jaundice, is proposed.

A patient with right upper quadrant pain showed normal tracer extraction and a prolonged hepatocellular phase during biliary imaging, findings that are most consistent with complete common duct obstruction. He had no other evidence of biliary tract obstruction and was diagnosed subsequently as having viral hepatitis. Hepatitis must be considered when biliary imaging suggests complete common bile duct obstruction.

Tc-99m IDA cholescintigraphy frequently provides information regarding nonbiliary pathology, such as small bowel obstruction. The cholescintigraphic finding of functional cystic duct obstruction concomitant with persistent small bowel dilatation and lack of progression of labeled bile suggests the diagnosis of gallstone ileus.

A case of acute gangrenous cholecystitis due to cystic duct obstruction by a metastasis from malignant melanoma detected by cholescintigraphy is presented.

The authors report a case in which a radionuclide hepatobiliary image was falsely indicative of cystic duct obstruction in a patient with an indwelling cholecystostomy tube and an externalized gallbladder-duodenal stent. Cystic duct patency was demonstrated radiographically shortly before and after the radionuclide study. The authors recommend that cystic duct obstruction indicated by a radionuclide hepatobiliary image be confirmed by another means if a cholecystostomy tube is present, or if the patient recently has undergone percutaneous gallbladder or cystic duct manipulations.

A Tc-99m PIPIDA scan was performed in a young auto accident victim who had a transient rise in serum bilirubin level. Initially, the stasis of activity in the right ureter was mistaken for activity in the common bile duct. Misinterpretation of biliary imaging studies can be prevented with awareness of pitfalls and readiness to obtain delayed images and additional images in different projections.