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

Hepatobiliary Imaging

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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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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

Pathways of IDA derivates

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HIDA Little used today

HIDA

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DISIDA (Disofenin)

85% extracted by the hepatocytes

Visualization of gallbladder and CBD when bilirubin > 8 ng/dl

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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

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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 > 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 cameraA large field of view with a low energy all

purpose or high resolution collimatorA 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 >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

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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 CBDDiverting 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 40–60 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 >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

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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

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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 18–24 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 gastritisCause of epigastric discomfort

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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

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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/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

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The End

Thank for Your Attention !