The cystic duct sign during morphine-augmented cholescintigraphy

Area of Science:

• Hepatobiliary imaging
• Radiology
• Nuclear medicine

Background:

• Hepatobiliary scintigraphy (HBS) is a key diagnostic tool for evaluating gallbladder and biliary tree pathology.
• Morphine is frequently administered during HBS to enhance visualization of the common bile duct and improve diagnostic accuracy.
• A dilated cystic duct can mimic gallbladder or lead to false-negative interpretations in HBS.

Observation:

• Transient visualization of the cystic duct was observed following intravenous morphine administration.
• This phenomenon occurred in a patient with a confirmed obstructing cystic duct calculus.
• The morphine-induced effect mimicked a non-obstructed system, potentially masking the underlying pathology.

Findings:

• Morphine's pharmacologic effects can accentuate the appearance of a "dilated cystic duct."
• This accentuation can lead to a false-negative interpretation of cholescintigraphy, particularly in cases of cystic duct obstruction.
• The transient nature of the visualization necessitates careful interpretation of HBS studies post-morphine administration.

Implications:

• Clinicians should be aware of morphine's potential to cause transient cystic duct visualization.
• This effect may lead to misdiagnosis of cystic duct obstruction if not recognized.
• Consideration of alternative imaging protocols or delayed imaging may be warranted in specific clinical scenarios to avoid false-negative results.