Examqo › Examqo library › Nuclear medicine › Renal, GI, brain, infection and paediatrics

Hepatobiliary and gastrointestinal scintigraphy

GI scintigraphy answers functional questions that anatomical imaging does not — is the cystic duct open (HIDA), where is a slow bleed (labelled red cells), is there ectopic gastric mucosa (Meckel), and how fast does the stomach empty.

לקריאה בעברית

Why it matters in the exam

HIDA in acute cholecystitis: Tc-99m mebrofenin is taken up by the liver and excreted into bile; if the gallbladder is not seen within 60 minutes, morphine (about 0.04 mg/kg) is given, which tightens the sphincter of Oddi so bile is redirected into the gallbladder, and imaging continues for 30 minutes, or delayed images are taken after 3–4 hours. Non-filling confirms cystic duct obstruction. The "rim sign" — increased liver activity around the gallbladder — suggests severe inflammation or gangrene. False positives: fasting shorter than 2–4 hours or longer than 24 hours, parenteral nutrition, severe illness and poor liver function; after prolonged fasting sincalide is given first.

A gallbladder ejection fraction after sincalide below 38% fits gallbladder dysfunction. In a jaundiced newborn: phenobarbital 5 mg/kg per day for 3–5 days before the study improves excretion; bowel activity excludes biliary atresia, and no excretion by 24 hours raises suspicion of it, but severe hepatitis, parenteral nutrition or cystic fibrosis can give the same picture. A postoperative bile leak appears as tracer outside the biliary tree.

GI bleeding: Tc-99m-labelled red cells (in vitro labelling is best) detect bleeding at a low rate of about 0.05–0.1 mL/min, more sensitive than angiography; a focus that appears and moves in a bowel pattern locates the source, and imaging can continue up to 24 hours. In brisk bleeding CTA is the first study. Meckel: pertechnetate is taken up by ectopic gastric mucosa; pretreatment with an H2 blocker improves sensitivity, and a barium study must not be done beforehand. Gastric emptying: a labelled solid meal, imaging up to 4 hours; retention above 60% at two hours or above 10% at 4 hours is delayed emptying. A Warthin tumour of the parotid retains pertechnetate even after lemon stimulation.

Key points

• HIDA — gallbladder non-filling after morphine confirms acute inflammation.
• Gallbladder ejection fraction below 38% — dysfunction.
• Bowel activity excludes atresia.
• Labelled red cells — slow bleeding.
• Meckel — pertechnetate after an H2 blocker.

Summary table

Free exam questions

In the full version for subscribers

• A simple algorithm
• Memory aid
• Exam traps
• 5 review cards
• Enough for IMLE

The full version is open to subscribers of: Nuclear medicine, Internal medicine, General surgery, Pediatrics.

Subscriber? Read the full topic Plans and prices 25 free questions

Sources

• SNMMI Procedure Standard for Hepatobiliary Scintigraphy, 2021 — Acute cholecystitis, morphine augmentation, gallbladder ejection fraction and biliary atresia
• SNMMI/EANM Practice Guideline for Gastrointestinal Bleeding and Meckel Diverticulum Scintigraphy, 2022 — Labelling, pretreatment and interpretation
• Consensus Recommendations for Gastric Emptying Scintigraphy (SNMMI and American Neurogastroenterology and Motility Society), 2008 — Standard meal and normal values

Sources are given for further reading; the text is written afresh and not copied from them.

Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.