Hepatobiliary nuclear medicine

HIDA

• Used to evaluate for cholecystitis typically

• Bilirubin is transported in the blood bound to albumin

  • Then removed from albumin by hepatocytes

    • Secreted into bile canaliculi and cleared by biliary tree into the bowel

• The IDA compounds will follow a similar pathway

  • HIDA

  • DISIDA

• Technique

  • No food for 4-12 hour

  • Narcotics must be stopped 6-12 hours before test

  • IV inject 5-10 mCi Tc-99m IDA

  • Take 1-5 min frames for 60 minutes

  • If at the end of 60 minutes the gallbladder is not filled

    • Do delayed imaging up to 4 hours after the original hour

    • Give morphine IV (0.04 mg/kg over 1 min)

  • If you need GB ejection raction

    • Give CCK IV (0.02 ug/kg over 10-30 minutes) then take dynamic images over the next 30 minutes

• Normal scan

  • Liver is well visualized by 5 minute

  • Heart disappears after 10 minutes (earlier is ok)

  • IDA will then begin to be excreted from the liver into the bile ducts and the liver will begin to decrease in visualization and the bile ducts will begin to be visualized

  • GB will be visualized within 60 minutes

  • Note that 2/3 of biliary flow will by pass the GB and go straight t to duodenum

  • Normal GB EF is >35%

• Abnormal study

  • Typical cause of acute cholecystitis is going to be an obstructive stone

    • Causes inflammation of GB which then cannot take in the radiotracer

  • If GB not seen after 1 hour —> get delayed images or use morphine

• Acute cholecystitis

  • GB fails to fill (GB not visualized) after 4 hours

  • GB not visualized within 30 minutes after morphine is given

  • NOTE: You can still see the tracer in the CBD and in duodenum, just will not see the GB

  • Rim sign - increased radiotracer activity in the areas of liver surrounding the GB fossa

    • A positive rim sign is associated with a 40% chance of perforated or gangrenous gallbladder

  • Cystic Duct sign

    • Focus of increased tracer uptake in the cystic duct proximal to the site of the obstruction

    • Shit just gets backed up I guess and accumulates making this pronounced focus of uptake

• Chronic cholecystitis & Biliary Dyskinesia

  • Findings below are characteristic but ultimately nonspecific

  • Normal routine scan

  • GB EF < 35%

  • Delayed GB visualization beyond 1 hour

Acute Cholecystitis

• GB fails to fill (GB not visualized) after 4 hours

• GB not visualized within 30 minutes after morphine is given

• NOTE: You can still see the tracer in the CBD and in duodenum, just will not see the GB

• Cystic duct sign (top pic)

  • Focus of increased tracer uptake in the cystic duct proximal to the site of the obstruction

  • Shit just gets backed up I guess and accumulates making this pronounced focus of uptake

• Rim sign (bottom pic)

  • Increased radiotracer activity in the areas of liver surrounding the GB fossa

  • A positive rim sign is associated with a 40% chance of perforated or gangrenous gallbladder

Chronic Cholecytitis & Biliary Dyskinesia

• Findings below are characteristic but ultimately nonspecific

  • Normal routine scan

  • GB EF < 35%

  • Delayed GB visualization beyond 1 hour

Pediatric HB NM

• Typically done in kids with jaundice to differentiate between biliary atresia and neonatal hepatitis

• 5-7 days of phenobarbital may be used to help diagnosed because it stimulates biliary excretion from the liver

Biliary Atresia

• Increased tracer uptake in liver but none in bile ducts or small bowel

• Image is garbage but basically shows uptake in liver and none in bowel

• Imaging should be performed for 24 hours

Liver & Spleen Nuc med imaging

• Typically evaluated with CT first because better but some instances nuc med can be used

• Tc-colloid is tracer

• Normal study in pic to right

• Indications

  • Focal nodular hyperplasia

  • Splenomegaly/splenosis

  • Colloid shift (cirrhosis)

  • Hepatic parenchymal lesions, whatever that means

Focal Hepatic Lesions on Tc99-colloid scan

• Increased and decreased is relative to background of liver parenchyma

• Increased uptake

  • FNH (top pic)

  • Regenerative nodule

• Decreased uptake

  • Cyst

  • Hematoma

  • Hemangioma

  • Abscess

  • Mets, specifically colon cancer mets

  • Cirrhosis (hepatoma?)

Pediatric Hepatobiliary Nuclear Medicine

Liver & Spleen Imaging