Nuclear Medicine in Gastroenterology

These flashcards cover key concepts associated with nuclear medicine applications in gastroenterology, focusing on various imaging techniques and their clinical implications.

Biliary Scintigraphy

A nuclear medicine imaging technique used to evaluate the biliary system.

Tc-99m IDA

A radiopharmaceutical used in biliary scintigraphy for visualizing bile flow.

• Iminodiacetic acid; i.v. injection

• is a chelating agent that binds technetium-99m. It is commonly used in liver and biliary tract imaging.

• behaves like bilirubin to allow assessment of liver function and biliary obstructions, and helps in diagnosing conditions such as cholestasis or biliary atresia.

Biliary Atresia

A neonatal disease characterized by inflammatory sclerosis and obliteration of intrahepatic & extrahepatic bile ducts.

• presents with jaundice, hypoproteinemia, impaired coagulation

Liver Hemangioma

The most common benign liver tumor, characterized by abnormally dilated vascular channels.

Meckel’s Diverticulum

• The most common congenital anomaly of the gastrointestinal tract.

• in 10-30% of cases - heterotopic gastric mucosa is present

Heterotopic Gastric Mucosa

Presence of gastric mucosa in abnormal locations, associated with Meckel's diverticulum.

• in 98% manifests with bleeding

• typically in patients under 40 years old

Tc-99m Pertechnetate

A radiopharmaceutical used to visualize heterotopic gastric mucosa.

• physiological uptake in gastric mucosa

Gastrointestinal Bleeding

A condition that can be localized using nuclear scintigraphy to determine the vascular origin of the bleed.

Tc-99m Sulfur Colloid

A radiopharmaceutical used to detect gastrointestinal bleeding.

Active Bleeding

Visible movement of radiopharmaceutical in the intestinal tract pattern during scintigraphy.

Protein Losing Enteropathy

A condition involving excessive protein loss through the gastrointestinal tract.

• associated with intestinal lymphangiectasia, Crohn disease, Menetrier disease, amyloidosis, intestinal fistula

Tc-99m Human Serum Albumin

A radiopharmaceutical used in the diagnosis of protein losing enteropathy.

• no patient preparation needed

Salivary Gland Scintigraphy

An imaging technique to assess the function of salivary glands and detect abnormalities.

• Indicated in:

1. duct system conditions - obstruction

2. xerostomia - Sjorgen Sy

Sjogren's Syndrome

An autoimmune disorder characterized by dry mouth and eyes due to impaired salivary gland function.

White Blood Cell Scintigraphy

A nuclear medicine imaging technique used to visualize sites of inflammation or infection.

• Indicated in: IBD dx.

• It involves tagging the patient's white blood cells with a radioactive tracer, allowing for targeted imaging of active disease areas in conditions such as inflammatory bowel disease (IBD)

Inflammatory Bowel Disease (IBD)

A chronic condition characterized by inflammation of the gastrointestinal tract.

Focal Uptake

• Localized increase in radiopharmaceutical uptake indicative of infection or inflammation

• observed during 24h imaging of abdomen & pelvis

  • shows same localization with increased uptake on every image

Patient Preparation for Scintigraphy

Pre-scan protocols, such as fasting, to ensure accurate results

• Tc-99m IDA → biliary scintigraphy (atresia)

  • fasting for 4 h - to ensure that the gallbladder is NOT contracted (not always possible in neonates → give b4 next meal)

  • phenobarbital 5mg/kg/day for 5days prior - activated liver excretory enzymes

• Tc-99m Red Blood Cells

  • none → liver hemangioma scintigraphy

• Tc-99m pertechnetate

  • fasting for 4 h → imaging of heterotopic gastric mucosa

  • none → salivary gland scintigraphy

• Tc-99m sulfur colloid & Tc-99m RBC → GI bleeding

  • none

• Tc-99m human serum albumin

  • none

• Tc-99m HMPAO

  • none

Imaging Duration

The length of time that images are taken post-injection for analysis.

Renal Clearance

The process of radiopharmaceutical excretion through urine after imaging.

Detection of Liver Metastases

Assessment of the liver for secondary tumors originating from other cancer sites.