HEPATOBILIARY IMAGING

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HEPATOBILIARY IMAGING

• Presented by
• Yang Shiow-wen
• 11/26/2001

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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

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Hepatobiliary Imaging

• Performed with a variety of compounds that share
  the common imminodiacetate moiety

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Structures of IDA derivates

• Blue color A polar component (the diacetate)
• Red A lipophilic component

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IDA-chelated Tc-99m

• A magnification of two imminodiacetate compounds
• Polar components chelated a Tc-99m molecule

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Pathways of IDA derivates

• The lipophilic component binding to hepatocyte
  receptors for bilirubin
• Transported through the same pathways as
  bilirubin, except for conjugation
• Excretion decreased with increasing bilirubin
  levels

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HIDA

• HIDA
• Little used today

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DISIDA (Disofenin)

• 85 extracted by the hepatocytes
• Visualization of gallbladder and CBD when
  bilirubin gt 8 ng/dl

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BRIDA (Mebrofenin)

• 98 extracted by the hepatocytes (bilirubin lt1.5
  mg/dL)
• Visualization of gallbladder and CBD when
  bilirubin gt 30 ng/dl
• Higher hepatic extraction

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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

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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

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Contraindications

• Hypersensitivity to
• IDA derivative
• Local anesthetics of the amide type
• With disturbances of cardiac rhythm or conduction
• Pregnancy Category C

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Requirements for DISIDA Scan

• Patient preparation fasted for 2-4 hours
• Otherwise delayed or non-visualization
• Fasted for gt 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

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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

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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

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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

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Interventions

• CCK (0.01-0.02 ug/kg)
• Fasting for gt24-48 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

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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

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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

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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

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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

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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)

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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

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Acute Cholecystitis

• When acute cholecystitis is suspected and the
  gallbladder is not seen within 4060 min
• 3 4 hr delayed images should be obtained
• Rule out chronic cholecystitis
• Premedication with CCK
• Morphine augmentation

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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

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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

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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

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Chronic Cholecystitis

• Ultrasound is the primary modality of choice
• S\S
• Usually having gall stones
• The cystic duct is not blocked
• More chronic pain

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Common Bile Duct Obstruction

• Delayed visualization of the gall bladder
• Clinical settings associated with physiologic
  failure of the gallbladder to filling
• e.g. fasting for gt24 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

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Common Bile Duct Obstruction

• S\S
• Hyperbilirubinemia (gt 5 mg/dl)
• Dilation of CBD (sonography, gt3 days)
• A history of pancreatitis (serum amylase)
• DISIDA scan
• High grade or a total CBD obstruction
• Sensitivity 95
• Detection immediately

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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 1824 hrs
• Suspected High grade CBD obstruction
• Severe hepatocellular dysfunction may appear
  similar

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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

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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

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Duodenogastric Bile Reflux

• Highly correlated with bile gastritis
• Cause of epigastric discomfort

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False Positive Study

• Gallbladder non-visualization in the absence of
  acute cholecystitis
• Insufficient fasting (lt2 4 hr)
• Prolonged fasting (gt24 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

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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)

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Reflux into Stomach
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Radioactivity in Left Subphrenic Space-I
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Bile Leak Post-cholecystectomy-II
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References

• http//www.vh.org/Providers/Lectures/IROCH/Biliary
  Nucs/BiliaryNucs.html (Virtual Hospital)
• http//www.cancerboard.ab.ca/about/ercdocs/diiso.h
  tml
• http//www.nuclearonline.org/PI/Bracco20mebrofeni
  n20doc.pdf
• http//www.snm.org/pdf/hb2.pdf
• http//www.vh.org/Providers/Textbooks/ElectricGiNu
  cs/Text/Hepatobiliary.html
• Chapter 38, Hepatobiliary Imaging, Darlene
  Fink-Bennett, P759-770

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The End

• Thank for Your Attention !