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HEPATOBILIARY IMAGING. Presented by Yang Shiow-wen 11/26/2001. Hepatobiliary Imaging. Evaluates hepatocellular function and patency of the biliary system Tracing the production and flow of bile from the liver through the biliary system into the small intestine
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HEPATOBILIARY IMAGING Presented by Yang Shiow-wen 11/26/2001
Hepatobiliary Imaging • Evaluates hepatocellular function and patency of the biliary system • Tracing the production and flow of bile from the liver through the biliary system into the small intestine • Sequential images of the liver, biliary tree and gut are obtained • A "HIDA" scan or a "DISIDA" scan
Hepatobiliary Imaging • Performed with a variety of compounds that share the common imminodiacetate moiety
Structures of IDA derivates • Blue color: A polar component (the diacetate) • Red: A lipophilic component
IDA-chelated Tc-99m • A magnification of two imminodiacetate compounds • Polar components chelated a Tc-99m molecule
Pathways of IDA derivates • Thelipophilic component : binding to hepatocyte receptors for bilirubin • Transported through the same pathways as bilirubin, except for conjugation • Excretion decreased with increasing bilirubin levels
HIDA • HIDA • Little used today
DISIDA (Disofenin) • 85% extracted by the hepatocytes • Visualization of gallbladder and CBD when bilirubin > 8 ng/dl
BRIDA (Mebrofenin) • 98% extracted by the hepatocytes(bilirubin <1.5 mg/dL) • Visualization of gallbladder and CBD when bilirubin > 30 ng/dl • Higher hepatic extraction
BRIDA (Mebrofenin) • Rapid biliary to bowel transit time • Taken into consideration when evaluating acute cholecystitis • Mebrofenin may be preferred over Disofenin in suspected biliary atresia
Indications • Functional assessment of the hepatobiliary system • Integrity of the hepatobiliary tree • Evaluation of suspected acute cholecystitis • Evaluation of suspected chronic biliary tract disorders • Evaluation of common bile duct obstruction • Detection of bile extravasation • Evaluation of congenital abnormalities of the biliary tree
Contraindications • Hypersensitivity to • IDA derivative • Local anesthetics of the amide type • With disturbances of cardiac rhythm or conduction • Pregnancy Category: C
Requirements for DISIDA Scan • Patient preparation: fasted for 2-4 hours • Otherwise delayed or non-visualization • Fasted for > 24 hrs or on TPN, a false-positive study may occur • Radiotracer • Adult • 1.5-5 mCi Tc-99m IDA compounds i.v. • 3 – 10 mCi for hyperbilirubinemia • Children • 0.05 – 0.2 mCi/kg • minimum of 0.3 – 0.5 mCi
Requirements for DISIDA Scan Additional information • History of previous surgeries, especially biliary and gastrointestinal • Time of most recent meal • Current medications • esp. opioid compounds • Delaying the study for 4 hr after the last dose • Bilirubin and liver enzyme levels • Results of ultrasound
Requirements for DISIDA Scan • Gamma camera • A large field of view with a low energy all purpose or high resolution collimator • A smaller field of view with a diverging collimator
Requirements for DISIDA Scan • Serial anterior views for 60 minutes • Until activity is seen in both the gallbladder (patency of the cystic duct) and the small bowel (patency of the common bile duct) • Every 5 minutes for 30 minutes • Once at 45 minutes • Once at 1 hour • Right lateral views • At 30, 60 minutes • Oblique views • Separate gallbladder from small bowel activity • Delayed views • At 2 hours, 4 hours, 6 hours or 24 hours after injection • Severely ill patient, suspected CBD obstruction, suspected biliary atresia
Interventions • CCK (0.01-0.02 ug/kg) • Fasting for >24-48 hours, or on TPN • Empty the gall bladder (low resistance to bile flow state) • Preferential gallbladder filling • Delayed biliary to bowel transit • Injection 30 min prior to the test • Administered slowly (3 – 5 min) • Prevent biliary spasm and abdominal cramps • Water (5-10 cc) • Distinguish transient duodenal activity from gallbladder
Interventions • Morphine sulfate (0.04-0.1 mg/kg) • When acute cholecystitis is suspected and the GB is not seen by 60 min • & Radiotracer within the small intestine • Enhancing sphincter of Oddi tone • Increasing pressure within the CBD • Diverting bile away from the sphincter of Oddi & into functionally obstructed sludge filled gallbladder
Interventions • Fatty meal stimulation • Gallbladder ejection fraction measurement • Phenobarbital • When biliary atresia is suspected • 5 mg/kg/day (orally) for 3 – 5 days prior to the study • Enhancing the biliary excretion of the radiotracer
Processing • Gallbladder ejection fraction (GBEF) • Using the immediate pre-CCK and the post-CCK data • Regions of interest (ROI) are drawn around the GB and adjacent liver (background) • Hepatic extraction fraction (HEF) • Index of hepatocellular function • Deconvolution analysis from ROI over the liver and heart
Normal Study • Immediate demonstration of hepatic parenchyma • Prompt clearance of the blood pool within the first 5 minutes • Biliary excretion should commence within 20 minutes (5-10 min) • Biliary ducts would visualize followed the gallbladder • Gallbladder and small bowels are visualized within 1 hour
Acute Cholecystitis • The most common indication • S\S • Nausea, vomiting, fever • Right upper quadrant pain post-prandially • Mild to moderate leukocytosis • Abnormal liver function test • Pain radiates to the back (scapula) • Obstruction of cystic duct • By a gallstone • Inflammation, edema, gallbladder mucous, or a tumor (5%)
Acute Cholecystitis • DISIDA scan • Sensitivity: 95%, specificity 93-96% • Positive predictive value: 92.1%, negative predictive value: 99% • Adequate filling of the gallbladder • Acute cholecystitis is effectively excluded • Cystic duct obstruction • Failure to visualize the gallbladder up to 4 hours
Acute Cholecystitis • When acute cholecystitis is suspected and the gallbladder is not seen within 40–60 min • 3 – 4 hr delayed images should be obtained • Rule out chronic cholecystitis • Premedication with CCK • Morphine augmentation
Acute Cholecystitis • Premedication with CCK • Same sensitivity and specificity • Disadvantages • Not differentiated chronic cholecystitis from normal • Nausea, vomiting, exacerbation of bladder pain • Missed acute cholecystitis exhibiting delayed gallbladder visualization • Without delayed views • Malrotaion, enterogastric reflux, masses displacing or inflammatory processes of the small bowel
Acute Cholecystitis • Ingestion of morphine sulfate • More accurately, less complication • Differential diagnosis for non-visualization of the gallbladder • Relaxation of the sphincter of Oddi • Imaging is usually continued for another 30 min • Contraindications • Absolute: Respiratory depression in non-ventilated patients, morphine allergy • Relative: acute pancreatitis
Acute Cholecystitis • The hallmark of acute cholecystitis (acalculous as well as calculous) • Persistent gallbladder non-visualization 30 min post-morphine or on the 3 – 4 hr delayed image • Rim sign • A band or rim of increased activity adjacent to gallbladder fossa • Associated with severe phlegmonous/gangrenous acute cholecystitis, a surgical emergency • Cystic duct obstruction, acute cholecystitis
Chronic Cholecystitis • Ultrasound is the primary modality of choice • S\S • Usually having gall stones • The cystic duct is not blocked • More chronic pain
Common Bile DuctObstruction • Delayed visualization of the gall bladder • Clinical settings associated with physiologic failure of the gallbladder to filling • e.g. fasting for >24 – 48 hr, severely ill or post-operative patients may result in GB non-visualization within the first hour • A larger dose of morphine (0.1 mg/kg) decrease the false positive rate • Separated from acute cholecystitis using morphine or delayed imaging • Reduced gallbladder ejection fraction in response to CCK • Indicative of chronic cholecystitis, gallbladder dyskinesia or the cystic duct syndrome • Visualization of the GB after the bowel
Common Bile Duct Obstruction • S\S • Hyperbilirubinemia (> 5 mg/dl) • Dilation of CBD (sonography, >3 days) • A history of pancreatitis (serum amylase) • DISIDA scan • High grade or a total CBD obstruction • Sensitivity: 95% • Detection immediately
Common Bile Duct Obstruction • Delayed biliary-to-bowel transit beyond 60 min raises the suspicion • Activity in the small bowel seen within 60 min does not entirely exclude partial CBD obstruction • When neither the gallbladder nor the small bowel are seen within 18–24 hrs • Suspected High grade CBD obstruction • Severe hepatocellular dysfunction may appear similar
Bile Leaks • Most appropriate non-invasive imaging technique for evaluation of bile leaks • Sensitivity: 87%, Specificity: 100% (2-3 ml of labeled bile) • Radiopharmaceutical activity • In an extrahepatic and extraluminal location • More intense with time • Differentiating intraluminal activity from a leak • Standing views in addition to decubitus views • Cinematic display • 3 – 4 hrs delayed imaging
Biliary Atresia • Excluded by demonstrating transit of radiotracer into the bowel • Failure of tracer to enter the gut • Hepatocellular disease • Immature intrahepatic transport mechanisms • Biliary atresia • CBD obstruction • Urinary excretion of the tracer (especially in diaper) may be confused with bowel activity
Duodenogastric Bile Reflux • Highly correlated with bile gastritis • Cause of epigastric discomfort
False Positive Study • Gallbladder non-visualization in the absence of acute cholecystitis • Insufficient fasting (<2 – 4 hr) • Prolonged fasting (>24 – 48 hr), especially total parenteral nutrition (despite CCK pre-treatment and Morphine augmentation) • Severe hepatocellular disease • High grade common bile duct obstruction • Severe intercurrent illness (despite CCK pre-treatment and Morphine augmentation) • Pancreatitis (rare) • Rapid biliary-to-bowel transit (insufficient tracer activity remaining in the liver for delayed imaging) • Severe chronic cholecystitis • Previous cholecystectomy
False Negative Study • Gallbladder visualization in the presence of acute cholecystitis • Bowel loop simulating gallbladder (drinking water may help to clarify anatomy) • Acute acalculous cholecystitis • The presence of the "dilated cystic duct" sign simulating GB. (Morphine should not be given) • Bile leak due to GB perforation • Congenital anomalies simulating gallbladder • Activity in the kidneys simulating gallbladder or small bowel (may be clarified by a lateral image)
References • http://www.vh.org/Providers/Lectures/IROCH/BiliaryNucs/BiliaryNucs.html (Virtual Hospital) • http://www.cancerboard.ab.ca/about/ercdocs/diiso.html • http://www.nuclearonline.org/PI/Bracco%20mebrofenin%20doc.pdf • http://www.snm.org/pdf/hb2.pdf • http://www.vh.org/Providers/Textbooks/ElectricGiNucs/Text/Hepatobiliary.html • Chapter 38, Hepatobiliary Imaging, Darlene Fink-Bennett, P759-770
The End Thank for Your Attention !