Podcast
Questions and Answers
What role does the sphincter of Oddi play in biliary function?
What role does the sphincter of Oddi play in biliary function?
Which of the following agents is NOT a Tc-labeled derivative of iminodiacetic acids (IDA) used for hepatobiliary imaging?
Which of the following agents is NOT a Tc-labeled derivative of iminodiacetic acids (IDA) used for hepatobiliary imaging?
What is the significance of elevated bilirubin levels in the context of hepatobiliary imaging?
What is the significance of elevated bilirubin levels in the context of hepatobiliary imaging?
In pediatric applications of hepatobiliary imaging, which condition is often considered for detection?
In pediatric applications of hepatobiliary imaging, which condition is often considered for detection?
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Which statement about bile is incorrect?
Which statement about bile is incorrect?
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What factor does NOT influence the dosage determination of 99mTc-IDA in patients?
What factor does NOT influence the dosage determination of 99mTc-IDA in patients?
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What happens to bile flow and gallbladder function when the sphincter of Oddi is contracted?
What happens to bile flow and gallbladder function when the sphincter of Oddi is contracted?
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Cold defects visualized on Tc99m-sulfur colloid images may indicate what?
Cold defects visualized on Tc99m-sulfur colloid images may indicate what?
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What is the effect of prolonged fasting on gallbladder visualization during imaging?
What is the effect of prolonged fasting on gallbladder visualization during imaging?
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What is a normal gallbladder ejection fraction (GBEF) value considered to be?
What is a normal gallbladder ejection fraction (GBEF) value considered to be?
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In which scenario should morphine not be given during the imaging procedure?
In which scenario should morphine not be given during the imaging procedure?
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What is the time duration for gallbladder emptying after sincalide administration?
What is the time duration for gallbladder emptying after sincalide administration?
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What imaging position allows for the best view of the liver and biliary tract?
What imaging position allows for the best view of the liver and biliary tract?
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What administration method is used for morphine if the gallbladder is not visualized?
What administration method is used for morphine if the gallbladder is not visualized?
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What could delayed visualization of the gallbladder indicate?
What could delayed visualization of the gallbladder indicate?
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What is the recommended administration rate for sincalide?
What is the recommended administration rate for sincalide?
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Which side effect is associated with the administration of sincalide?
Which side effect is associated with the administration of sincalide?
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What does nonvisualization of the gallbladder likely indicate?
What does nonvisualization of the gallbladder likely indicate?
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What is the primary physiological role of bile in the digestive system?
What is the primary physiological role of bile in the digestive system?
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What effect does elevated bilirubin levels have on tracer uptake during hepatobiliary imaging?
What effect does elevated bilirubin levels have on tracer uptake during hepatobiliary imaging?
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Which of the following components does NOT form part of the biliary tract?
Which of the following components does NOT form part of the biliary tract?
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Which factor is least likely to influence the distribution of radiopharmaceutical agents in hepatobiliary imaging?
Which factor is least likely to influence the distribution of radiopharmaceutical agents in hepatobiliary imaging?
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What is the primary reason for discontinuing narcotics and sedatives before hepatobiliary imaging?
What is the primary reason for discontinuing narcotics and sedatives before hepatobiliary imaging?
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In pediatric hepatobiliary imaging, choledochal cysts are associated with which of the following?
In pediatric hepatobiliary imaging, choledochal cysts are associated with which of the following?
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What is the correct dosage range for adults receiving 99mTc-IDA based on normal conditions?
What is the correct dosage range for adults receiving 99mTc-IDA based on normal conditions?
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Which condition should hepatobiliary imaging help to rule out when a patient presents with upper abdominal pain?
Which condition should hepatobiliary imaging help to rule out when a patient presents with upper abdominal pain?
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What is the primary purpose of administering sincalide during hepatobiliary imaging?
What is the primary purpose of administering sincalide during hepatobiliary imaging?
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Which timing is most appropriate for administering morphine during the imaging procedure?
Which timing is most appropriate for administering morphine during the imaging procedure?
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What could be the result of administering both sincalide and morphine in close succession?
What could be the result of administering both sincalide and morphine in close succession?
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What finding during imaging might indicate acute cholecystitis?
What finding during imaging might indicate acute cholecystitis?
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Which of the following factors does NOT affect the speed of tracer uptake in hepatobiliary imaging?
Which of the following factors does NOT affect the speed of tracer uptake in hepatobiliary imaging?
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What side effects are most commonly associated with sincalide administration?
What side effects are most commonly associated with sincalide administration?
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Why might a patient with high bilirubin levels have delayed tracer clearance?
Why might a patient with high bilirubin levels have delayed tracer clearance?
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In the interpretation of imaging results, what does the absence of tracer excretion into the bowel within 24 hours suggest?
In the interpretation of imaging results, what does the absence of tracer excretion into the bowel within 24 hours suggest?
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What duration of gallbladder emptying is generally expected after sincalide administration?
What duration of gallbladder emptying is generally expected after sincalide administration?
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What condition could prolong the visualization of the gallbladder during imaging?
What condition could prolong the visualization of the gallbladder during imaging?
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Study Notes
Hepatobiliary Imaging
- Biliary Tract Components: Canaliculi, right and left hepatic ducts, common hepatic duct, cystic duct, common bile duct, and sphincter of Oddi.
- Bile Flow: Bile flows from canaliculi to hepatic ducts, then common hepatic duct, and finally to the duodenum via the sphincter of Oddi.
- Gallbladder Function: Stores bile when the sphincter of Oddi is contracted and releases it into the duodenum for digestion.
- Bile Function: Emulsifies fats, promotes peristalsis, and aids in fatty acid absorption.
- Bile Production: Bile is produced by erythrocyte breakdown and hepatocyte metabolism.
- Bile Secretion Stimulation: Cholecystokinin (CCK) stimulates gallbladder bile release when fatty foods enter the duodenum.
Clinical Indications
- Upper Abdominal Pain: Hepatobiliary imaging helps rule out cystic duct obstruction (acute cholecystitis) in patients with upper abdominal pain.
- Jaundice: Imaging differentiates between causes of jaundice, including biliary tract obstruction.
- Post-Surgical Evaluation: Images assess bile drainage and reflux following surgical procedures.
- Cold Defects (Tc99m-sulfur colloid): May indicate normal or abnormal variants in the biliary system.
- Pediatric Applications: Detects choledochal cysts, biliary atresia, and other congenital biliary tree anomalies.
Radiopharmaceuticals
- Agents: Mebrofenin, disofenin, lidofenin (Tc-labeled iminodiacetic acids).
- Drug Distribution: Compounds are extracted from the blood by hepatocytes and transported into canaliculi with bile.
- Bile Flow Tracking: IDA compounds follow bile flow, visualizing the biliary system.
- Factors Affecting Uptake: IDA compound structure, hepatic blood flow, hepatocyte health, and bilirubin level.
- Bilirubin Effects: High bilirubin levels reduce tracer uptake, potentially requiring higher dosages.
- Dosage: Adult dosage of 99mTc-IDA varies from 2 to 8 mCi, adjusted for serum bilirubin.
Patient Preparation
- Cystic Duct Obstruction: Bile flow into the gallbladder rules out cystic duct obstruction.
- Medication Discontinuation: Narcotics, sedatives, and drugs that relax the sphincter of Oddi should be stopped before imaging.
- Morphine Effects: Opiates increase sphincter tone, promoting gallbladder filling.
- Fasting: 2–4 hours before, but not exceeding 24 hours, to prevent gallbladder emptying of tracer.
- Fasting Rationale: Prevents tracer emptying after a fatty meal.
Imaging Procedure
- Procedure Start: Imaging begins after tracer injection using a scintillation camera with a low-energy collimator.
- Patient Position: Supine position for simultaneous liver, biliary tract, and small intestine imaging.
- Image Acquisition: Sequential 5-minute images over 45–60 minutes.
- Initial Projections: Anterior oblique or right lateral views after the first hour for bowel assessment.
- Delayed Imaging: Obtain views up to 24 hours if gallbladder or bile ducts aren't initially visualized.
- Delayed Small Intestine Views: Acquire if gallbladder and common bile duct are visualized but no tracer in the small intestine.
Sincalide (Kinevac)
- Usage: Empties the gallbladder before injecting the radioactive tracer.
- Administration: 0.01–0.02 g/kg intravenously over 3–5 minutes, 30–60 minutes before injection.
- Indications: Prolonged fasting, hyperalimentation.
- Administration Timing: Typically given 60 minutes after tracer to visualize the gallbladder and calculate GBEF.
- Effect on Gallbladder: Empties the gallbladder; administered before and after tracer for GBEF calculation.
- Morphine Interaction: Avoid administering after morphine to avoid potential interference and inaccurate GBEF.
- Gallbladder Emptying Time: Typically begins 2 minutes after, lasting approximately 11 minutes.
- Acquisition: 30-minute image acquisition at 1-2 frames/minute after infusion.
- Normal GBEF: Generally 35% or greater; less than 35% may suggest acute acalculous cholecystitis.
- Contraindications: Hypersensitivity, intestinal obstruction.
- Side Effects: Nausea, abdominal pain, urge to defecate, dizziness, flushing.
Morphine Sulfate (Astranorph, Duramorph)
- Administration: Intravenously if gallbladder isn't visualized within 40–60 minutes after tracer.
- Effect: Contracts sphincter of Oddi, increasing bile duct pressure, forcing tracer into the gallbladder.
- Nonvisualization After Morphine: Increased likelihood of acute cholecystitis.
- Dose: 0.04–0.1 mg/kg intravenously over 2–3 minutes.
- Imaging Duration: Continued for approximately 30 minutes post-injection.
- Contraindications: Premature infants, respiratory distress, morphine allergy, acute pancreatitis.
Phenobarbital (Luminal)
- Use: Differentiates biliary atresia from other neonatal jaundice causes.
- Administration: Pretreatment at 5 mg/kg/day for 3–5 days before imaging.
- Interpretation: Tracer excretion into the bowel within 24 hours suggests non-obstructive jaundice; otherwise, it suggests biliary atresia.
- Contraindications: Patient allergies or respiratory depression.
- Adverse Effects: Respiratory depression, drowsiness, hyper-excitability in children, rash, nausea, vomiting.
Image Findings
- Tracer Uptake Times: Hepatocytes (minutes), hepatic ducts/gallbladder (15–30 minutes), gallbladder (45–60 minutes), small intestine (30 minutes).
- Low GBEF (<35%): Possible acute acalculous cholecystitis.
- Nonvisualization of Gallbladder: Indicates cystic duct obstruction (acute cholecystitis).
- Delayed Gallbladder Visualization: Possible chronic cholecystitis.
- Small Intestine Issues: May indicate common bile duct obstruction.
- Bile Outside the System: Possible bile leak.
Technical Considerations
- Prolonged Fasting: Thick, viscous bile can lead to gallbladder non-visualization.
- Elevated Bilirubin: Increased bilirubin delays hepatocyte tracer clearance, possibly requiring identification on lateral/oblique views due to kidney excretion.
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Description
Explore the essential components and functions of the hepatobiliary system, including bile flow, bile production, and the clinical implications of hepatobiliary imaging. This quiz also addresses the role of imaging in diagnosing conditions such as acute cholecystitis and jaundice.
